UNIVERSITY OF GHANA 

 

 

 

EVALUATION OF SELECTED LOCAL SPICES ON SENSORY AND 

MICROBIAL CHARACTERISTICS OF FRESH PORK SAUSAGE 

 

 

 

BY 

COLEMAN FRED NEWMAN 

10361068 

 

 

THIS THESIS IS SUMBMITTED TO THE UNIVERSITY OF GHANA LEGON, 

IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD 

OF MASTER OF PHILOSOPHY ANIMAL SCIENCE DEGREE 

 

DEPARTMENT OF ANIMAL SCIENCE 

COLLEGE OF BASIC AND APPLIED SCIENCES 

UNIVERSITY OF GHANA 

 

 

JULY, 2015

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DECLARATION 

I hereby declare that this thesis which  is submitted to the Department of Animal 

Science, College of Basic and Applied Sciences, University of Ghana, for the award of 

Master of Philosophy in Animal Science degree is the result of my own original work 

and that no part of it has been presented for another degree in this university or 

elsewhere. All assistance towards the production of this work and all the references 

contained herein have been duly credited.  

 

 

…………………………….......    …………………………………. 

COLEMAN FRED NEWMAN              DATE 

              STUDENT 

 

 

 

…………………………….......    …………………………………. 

DR. SAMUEL OHENE-ADJEI                 DATE 

           SUPERVISOR                                                              

 

 

…………………………….......    …………………………………. 

PROF. ANNA R. BARNES                                                          DATE 

    CO- SUPERVISOR  

 

 

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DEDICATION 

I dedicate this work to my late mother; Rose Esinu Betsoe, my foster parents; Mr. & 

Mrs. Beresford Ruth, my wife; Mildred Anthonio Coleman and my son Nii Noi Ridley 

Eyram Coleman. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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ABSTRACT 

Xylopia aethiopica (African pepper) and Monodora myristica (African nutmeg) are used 

as spices in Ghanaian local dishes and as traditional medicine. The objective of this study 

was to substitute two spices in “normal” fresh pork sausage formulation with selected 

local spices and evaluate their effect on sensory and microbiological characteristics of 

the product. A 4x4 factorial design was used with 4 spice treatments (Control – Syzygium 

Gaertner (clove), Allium cepa (onion), Piper nigrum (white pepper) and Myristica 

fragrans (nutmeg); African pepper (AP) substituted for white pepper; African nutmeg 

(AN) substituted for nut meg (Myristica fragrans); and combination of AP and AN  

(AP*AN) at 4 inclusion levels (0%, 0.05%, 0.1% and 0.15%).  AP and AN were 

obtained from the local market in Accra. They were cleaned, dried and blended. The 

spices were irradiated with dose of 10KGY to reduce microbial load. The experiment had 

three replicates each replicate was made up of lb treatments. Six trained panelists 

evaluated the sausages using a 15 cm continuous scale on six sensory parameters 

(crumbliness, juiciness, palatability, saltiness, off flavour and overall liking), the 

formulated sausages with the selected local spices at varying concentrations did not 

differ (p  ˃0.05) from  the control product in all the sensory parameters. However, AP 

treated sausage at 0.15% was overall rated high. Culture of specimen-Aerobic bacteria, 

coliforms and E. coli were counted for the respective treatments stored for 0, 3, and 6 

days at 4
o
C. Substituting nutmeg with AN up to 0.15% significantly (p ˃ 0.05) increased 

aerobic bacteria count. However, the substitution did not affect coliform and E. coli 

counts. Microbial count during storage at 0, 3 and 6 days at 4
o
C exhibited different 

growth patterns. For aerobic plate count, mean log10 CFU/g count for aerobic bacteria 

and coliforms significantly increased between day 0 and day 3 and decreased from day 3 

to 6. Coliform, mean log count similarly increased from day 0 to day 3. No significant (p 

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 ˃0.05) difference in log count was observed from day 3 to day 6. E coli log10 CFU/g 

count decreased from day 0 to day 3, however, a significant increase in log count was 

observed from day 3 to day 6. The present study shows that Xylopia aethiopica and 

Monodora myristica can be used to substitute for Piper nigrum and Myritica fragrans 

respectively, in the manufacture of fresh pork sausages without affecting the sensory 

attributes and overall liking of the product. However, the addition of such spices could 

alter microbial profiles significantly. 

  

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ACKNOWLEDGEMENTS 

I wish to express my profound gratitude to the Almighty God for the numerous blessings 

He bestowed on me throughout my study period. 

My heartfelt gratitude goes to my major supervisor, Dr. Samuel Ohene-Adjei, for his 

noble hearted help, cooperation, and encouragement which have instilled in me the spirit 

of confidence to successfully complete this research work. 

I am greatly indebted to my co-supervisor, Prof. Anna R. Barnes, for her dedication, 

commitment and invaluable suggestions towards the success of this research. 

I thank the Head of Department of Animal Science and all Senior Members for their 

suggestions, which helped me to improve on the work. I acknowledge support of Mr 

Victor Coleman, Eric Coleman, Maj.Gen.(Rtd) Carl Coleman, Mrs Mildred Yaa 

Coleman, principals of Damongo Agric College and Kwadaso Agric College; Mr R.A. 

Ayamga and Mr E. Tawiah respectively and Mr .Justice Norvienyeku  as well as Mr. 

Alex Addo, Mr J Quaye, Mr Davis for their help in the lab works and  data collection. 

My sincere gratitude goes to the Methodist University College Ghana for the sponsorship 

given to me for this study. 

Appreciation to Prof. F. Fianu, Rev. Prof. E. Marfo, Dr Rockson and all staff of 

Methodist University College Ghana (MUCG) Wenchi Campus, Mr Dennis Owusu 

Adjei Mr. MacCarthy Vuvor and Mrs. Rejoice Frimpong, all of Department of Animal 

Science, University of Ghana, for their inspiration and encouragement throughout my 

study period. 

Finally, my warm gratitude to Mrs G.J. Alomenu and family, my lovely sisters (Alice 

Naa Coleman, Betty Dede Coleman, Freda Coleman, Peace Bani, Mary Bani and 

Mawuse Bani), brothers (Wisdom K. Vorvor, Chris Coleman, Nortey Coleman and Eric 

Jnr Coleman) as well as good friends especially Mr. Ben Dei, Mr Walter Konglo, Mr 

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Kweku Aboagye, Mr Eric Afari my parents –in-law (Mr Kofi Anthonio & Mrs Mary 

Anthonio and family) and finally to staff of Damongo Agric College, for their tender-

loving care extended to me in the course of pursuing this work.  

To all who contributed in diverse ways for making this work successful, I say may God 

richly bless you all. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  

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LIST OF ACRONYMS AND ABBREVIATIONS 

APC  - Aerobic Plate Count  

BHA  - Butylated hydroxyanisole 

BHT  - Butylated hydroxytoluene 

CPF                        - Cryogenically Processed food 

DLG                       - De La Grenada Industries Limited 

EBO                       - Encyclopedia Britannica Online 

EOs   - Essential Oils  

ERH  - Equilibrium Relative Humidity  

      FDA                       - Food and Drug Administration 

GI   - Gastrointestinal  

      GIPC                      -  Ghana Investment Promotion Centre 

LIPREC   - Livestock and Poultry Research Center 

MIC  - Minimum Inhibitory Concentration 

MPL  - Maximum Permissible Limit  

NRCS                     -           Natural Resources Conservation Services 

NZFSA                   -           New Zealand food safety Authority 

TBA  - Thiobarbituric acid 

TBHQ  - Ter-butylhydroquinone  

 

 

 

 

 

 

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TABLE OF CONTENTS 

Content           Page 

DECLARATION ................................................................................................................. i 

DEDICATION .................................................................................................................... ii 

ABSTRACT ......................................................................................................................iii 

ACKNOWLEDGEMENTS ................................................................................................ v 

LIST OF ACRONYMS AND ABBREVIATIONS ......................................................... vii 

TABLE OF CONTENTS ................................................................................................viii 

LIST OF TABLE .............................................................................................................. xii 

LIST OF FIGURES .........................................................................................................xiii 

 

CHAPTER ONE ................................................................................................................. 1 

INTRODUCTION .............................................................................................................. 1 

1.1 Background ............................................................................................................... 1 

1.2 Problem Statement .................................................................................................... 4 

1.3 Justification ............................................................................................................... 5 

1.4 Hypothesis ................................................................................................................. 5 

1.5 Objective of the Study............................................................................................... 5 

1.6 Specific Objectives ................................................................................................... 5 

 

CHAPTER TWO ................................................................................................................ 6 

LITERATURE REVIEW ................................................................................................... 6 

2.1 Sausage Development ............................................................................................... 6 

2.3 Some Selected Spices and their Characteristics ........................................................ 9 

2.3.1 Mace (Myristica fragrans) ................................................................................. 9 

2.3.2 White Pepper (Piper nigrum) ........................................................................... 10 

2.3.3 Onion (Allium cepa) ......................................................................................... 11 

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2.3.4 Marjoram (Origanum majorana) ..................................................................... 11 

2.3.5 Ginger (Zingiber officinale) ............................................................................. 12 

2.3.6 Clove (Syzygium Gaertner) .............................................................................. 13 

2.3.7 African Pepper (Xylopia aethiopica) ................................................................ 14 

2.3.8 The African Nutmeg (Monodora myristica) .................................................... 16 

2.4. Uses of Spices ........................................................................................................ 17 

2.4.1 Flavour Enhancer ............................................................................................. 18 

2.4.2 Antimicrobial Properties of Spices ................................................................... 19 

2.4.3. Antioxidant Activity of Spices ........................................................................ 22 

2.4.4. Medicinal Properties of Spices ........................................................................ 24 

2.5 Microbial Composition of Fresh Sausage ............................................................... 26 

2.5.1 Spoilage Bacteria .............................................................................................. 27 

2.5.2 Food –Borne Pathogens. ................................................................................... 28 

2.6 Factors Influencing Shelf Life of Sausages ............................................................ 30 

2.6.1 Effect of Moisture Content of Spices on Shelf life Meat Product .................... 30 

2.6.2 Influence of Nutrient Source on Microbial Growth ......................................... 32 

2.6.3 pH and Acidity ................................................................................................. 33 

2.6.4 Temperature ...................................................................................................... 33 

2.6.5 Impact of Time ................................................................................................. 34 

 

CHAPTER THREE .......................................................................................................... 35 

MATERIALS AND METHODS ..................................................................................... 35 

3.1. The Study Area ................................................................................................... 35 

3.1.1 Experimental Design ........................................................................................ 35 

3.2. Preparation of African Nutmeg (AN) and African Pepper (AP) ........................... 35 

3.2.1 Sausage Preparation ......................................................................................... 36 

3.2.2. Sensory Evaluation .......................................................................................... 36 

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3.3 Plate Counts ............................................................................................................ 37 

3.4 Statistical Analysis .................................................................................................. 37 

 

CHAPTER FOUR ............................................................................................................ 38 

RESULTS ......................................................................................................................... 38 

4.1. Sensory Evaluation ................................................................................................ 38 

4.2. Microbial Analysis ................................................................................................. 42 

 

CHAPTER FIVE .............................................................................................................. 45 

DISCUSSION ................................................................................................................... 45 

5.1. Sensory Evaluation ................................................................................................ 45 

5.2. Microbial Count ..................................................................................................... 47 

 

CHAPTER SIX ................................................................................................................. 50 

CONCLUSION AND RECOMMENDATIONS ............................................................. 50 

6.1 Conclusion .............................................................................................................. 50 

6.2 Recommendations ................................................................................................... 50 

 

REFERENCES ................................................................................................................. 51 

APPENDICES .................................................................................................................. 75 

Appendix 1: Sausage Classification ................................................................................. 75 

Appendix 2: Classification of Natural Spices Commonly Found in Ghana ..................... 77 

Appendix 3: Phytochemicals Properties of Monodora myristica ..................................... 79 

Appendix 4: Formulations ................................................................................................ 80 

Appendix 5:  Common Name, Scientific and Origins of Xylopia aethiopica and 

Monodora myristica .......................................................................................................... 81 

Appendix 6: Meat Lab - Evaluation Sheet ....................................................................... 82 

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Appendix 7:  SAS Syntax for Sensory Data ..................................................................... 90 

Appendix 8: SAS Syntax for Bacteria log Count Data ..................................................... 91 

 

          

 

 

 

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LIST OF TABLE 

Table 1. Mean Crumbliness and Juiciness ........................................................................ 38 

Table 2. Mean Palatability and Saltiness .......................................................................... 40 

Table 3. Mean Off-Flavour and Overall-Liking ............................................................... 41 

Table 4. (Log10 CFU/g) Count of Aerobic Bacteria, Coliforms and E. coli ..................... 43 

Table 5. Log10 CFU/g Count of Aerobic Bacteria, Coliforms and E. coli During Storage

 .......................................................................................................................................... 44 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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LIST OF FIGURES 

Figure 1: Proximate composition of Monodora myristica ............................................... 78 

Figure 2: Proximate composition of Xylopia aethiopica .................................................. 78 

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LIST OF PLATES 

Plate 1: Unripe (fresh) fruits of Xylopia aethiopica ......................................................... 83 

Plate 2: Dried fruits of Xylopia aethiopica ....................................................................... 84 

Plate 3: Dried nuts of Monodora myristica ...................................................................... 85 

Plate 4: Tote boxes to transport samples for irradiation ................................................... 86 

Plate 5: Panelists evaluating the samples .......................................................................... 87 

Plate 6: Counting of microbial load .................................................................................. 88 

Plate 7: Microbial load on agar ......................................................................................... 89 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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CHAPTER ONE 

INTRODUCTION 

1.1 Background 

Spices are dried seeds, flowers, fruits, barks, roots, leaves of plants or vegetative 

substances of different plants used in small quantities as food additives (Food and 

Agriculture Organization (FAO), 2010), and have been used in seasoning foods since 

time immemorial and at the same time serve as dietary supplements (Obadina and 

Ogundimu, 2011). Spices can improve the palatability; enhance flavour and visual appeal 

of dull diets. Piquant flavors are valued for other properties like stimulation of appetite, 

carminative and anti-oxidant effects and promotion of digestion (Takeda et al., 2008). 

 

Some chemical food additives however, have adverse side effect on human health 

(Tuula, 1994; Bridges and Bridges, 2007). Spices do not exhibit any toxicity at levels 

used and consumed (Oiye et al., 2012), in view of these, spices have become the most 

ideal food additives. Pungent spices can cause sweating, which may result in a cooling 

sensation in tropical climates; on the other hand, they can add a sense of inner warmth 

when present in cooked foods used in cold climates (Takeda et al., 2008).  Research 

shows that deterioration of human health may correlate with food products and food 

additives (Tuula, 1994). Most importantly, spices are used in preservation of meat and 

meat products such as sausages.  

 

Sausages play an important role in the nutrition of man. They are chopped or 

comminuted and seasoned meats that are formed into symmetrical shapes. They are more 

economical than whole meat cuts as they are produced from trimmings from primal cuts 

and by-products of meat (Jihad et al., 2009). Sausages are the most appetizing and 

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widely utilized meat product among all processed meats, and are of many varieties 

depending upon mode of manufacturing (FAO, 2010). The main ingredients of sausages 

are lean meat, fat and additives such as salts, spices and seasoning. Preservatives used to 

prevent microbial spoilage and to enhance colour and flavour include inorganic 

chemicals, such as salt, nitrite or nitrate and sodium  metabisulphite. Some ingredients 

which are locally unavailable, and need to be imported create production hitches (Oiye et 

al., 2012).  

 

Foods preserved with natural additives, which are generally recognized as safe have 

gained a wider interest in the meat industry for their potencies as antimicrobial and 

antioxidant e.g. oregano, clove, cinnamon, citral, garlic, coriander, rosemary, parsley, 

lemongrass, sage and vanillin (Annalisa et al., 2012; Angioni et al., 2004; Arques et al., 

2008; Daferera et al., 2000; Davidson and Naidu, 2000; Gutierrez et al., 2008). 

 

 The active components of spices and herbs are commonly found in the essential oil 

fractions. It is well established that most of them have a wide spectrum of antimicrobial 

activity, against food-borne pathogens and spoilage bacteria (Vijay et al., 2012; 

Gutierrez et al., 2008 ; Gutierrez et al., 2009). Common spices used in sausage making 

include; paprika, mace, nutmeg, garlic, onion, sage, black pepper, white pepper, red 

pepper, ginger, rosemary, cinnamon and cloves. 

 

Notably, most packaged spices imported by developing countries are exported in raw 

forms to developed worlds, where they are processed repacked and re-exported after 

significant value addition in the form of packaging and blending (SADC Trade, 2005) 

and decontamination by irradiation. According to FAO (1998), West and Central Africa 

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3441195/#B56
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3441195/#B57


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sub-regions have identified a large number of under-utilized species of plants that are 

important to livelihood of local populations. Some of these indigenous spices have been 

used in Ghanaian homes to prepare local dishes across the entire country, as flavour and 

taste enhancers (Dieu et al., 2006). Even though these spices have been in use for 

centuries, there is inadequate information about their effects on nutritional value 

improvement, flavour enhancement and shelf life extension of meat products 

(Ekeanyawu et al., 2010). Examples of these local spices include; African nutmeg and 

African pepper. 

 

Sausage production in the developing world presents many problems, such as religious 

belief concerning pig and cattle consumption, while some people do not consume certain 

parts or organs of slaughtered animals. However, opportunities for profitable sausage 

production  exist where meat resources are locally available, as livestock production and 

spices farming offers excellent raw materials for the product processing (FAO, 2010).  

 

The ever-growing increased consumption of sausage in Ghana calls for the exploration 

of local spices in sausage manufacturing to cut down cost of production and make 

production more convenient. The growing consumer interest in „ready- to- eat‟ meat 

products such as some varieties of sausages has led to higher rate of importation of the 

meat products which saw Ghana importing 1,362 metric ton (MTs) of  sausages in 1999 

with an increase of 159 percent over the imports in 1998, Ghana Investment Promotion 

Centre (GIPC) (2000). The trend shoots up from 3063 MTs in 2008 to 3285 MTs in 

2009, African Development Bank (ADB) (2011). 

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1.2 Problem Statement 

In most countries, people prefer sausages made from beef and chicken. Pork suffers 

many negative attitudes because of religious practices and unwholesome perception 

attached to it (Antwi-Boateng et al., 2013).  Pork is not sold at the local market/meat 

shop that is under the control of Muslims because of their religious taboos. People 

consider pigs as dirty animals and as such their meat are unhealthy. Another factor 

crippling the pork industry is the high rate of importation of pork (Antwi-Boateng et al., 

2013). Meanwhile, demand for animal protein has increased in the world due to the 

increasing human population and it puts pressure on producers to improve efficiency of 

animal production. Although meat consumption figure in Ghana is low, sausage 

consumption on the other hand is on the increase (ADB, 2011). Besides, sausage 

manufacture does not only help minimize protein deficiency but also add value to pork 

and easier to consume by all including children and the elderly (Sebranek, 2003). 

 

 Most spices used in local sausage production are exotic. High cost of imported spices 

compared with local spices, lack of development of local plant resources of spice 

potential, cultivar selection, large-scale cultivation, processing and packaging for local 

and international markets and high loads of microbial contamination are major problems 

facing the spice industry in Ghana. Additionally, research to improve the acceptability 

and marketability of local spices is lacking. How much spices are imported annually? 

What is the cost to the economy of the nation? Are there potential substitutes? What is 

the current use of potential substitutes? Why have they not been used in sausage 

manufacturing? The development of new and improved quality spices will be beneficial 

to the food and meat industry. There is therefore the need to evaluate these selected local 

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spices on sensory and microbial characteristic of fresh sausage to cut down cost and 

promote local spices as well. 

 

1.3 Justification 

The selected local spices are available in the local markets and affordable compared to 

imported ones. The results of this study will provide information on the potential use of 

local spices in sausage production.  

 

 1.4 Hypothesis 

African pepper and African nutmeg can be substituted for white pepper and nutmeg in 

sausage with no deleterious effect on sensory and microbial characteristics of fresh pork 

sausage. 

 

1.5 Objective of the Study 

The objective of this study is to evaluate two selected local spices (African pepper and 

African nutmeg) on sensory and microbial characteristic of fresh pork sausage. 

 

1.6 Specific Objectives  

The specific objectives of this study are to evaluate; (i) the effect of African pepper and 

African nutmeg on the sensory characteristics of fresh pork sausage (FPS); on 

significance. (ii) the effect of the spices on microbial load in sausages. 

 

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CHAPTER TWO 

LITERATURE REVIEW 

2.1 Sausage Development  

Sausage manufacture evolved as a move or plan to economize and preserve meat that 

could not be consumed or utilized fresh at slaughter. The manufacturing of sausages by 

man began over two thousand years ago (Oscar, 1998). They are one of the oldest 

prepared foods, whether cooked or eaten immediately or dried to various degrees 

(FAO, 1985). In the olden days, people in the western world did not have refrigerator 

to preserve their meat hence sausage making was developed to overcome the problems 

of wastage and spoilage.  

 

The modern word “sausage” is derived from the Latin word “salsus,” which means 

“salted” (Wijnker et al., 2006). The preparation of sausages began with a simple 

process of salting and drying meats. Sausages have been produced from different 

meats such as beef, pork, chicken, fish and buffalo meat (Sachindra et al., 2005). In 

addition, there are different types of sausages produced throughout the world based on 

the geographical location and the methods employed. Appendix1, described different 

sausages based on specific characteristics. For example; fresh sausage, dry and semi-

dry sausage; cooked sausage; smoked sausages; and cooked meat specials (Rust, 1987 

; Romans et al., 2001) and normally pork is chief meat for fresh sausages.  

 

According to Holness et al. (2005), for a number of years, pork consumption in the 

developing world had shown a steady increase at the expense of beef. This in part could 

be attributed to the lower fat content and healthier image of pork. Orr and Shen (2006) 

revealed that, pigs are the main source of meat in the world (40%, 93 million metric 

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http://www.oscarenterprises.f2s.com/sausage_history.html


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tons), China, European Union, United States, Brazil and Canada being the major 

producers and consumers. 

 

In developing countries, pig production makes a significant contribution to household 

economies and food security. In addition, it also contributes to improving the 

nutritional status of the rural poor. Pigs yield on the average four to five times more 

meat than cattle per ton of live weight (Eusebio, 1980). When compared with cattle and 

other ruminants, pigs have some major potential advantages including their ability to 

produce meat without contributing to the deterioration of the natural grazing lands 

(Holness, 1991). Pigs are prolific because they are capable of producing large litters 

after a relatively short gestation period.  

 

2.2 Importance of  Pork as raw material in Sausage Manufacturing 

The benefits of pig production cannot be underestimated. Besides, domestic pigs can be 

found worldwide because of their extraordinary importance in the production of red 

meat, lard and cured products. Their production is one of the fastest ways of meat 

production as they have a short gestation period, large litter size and a source of 

employment as well as means of eradication of poverty especially the developing 

countries. Whittemore (1980) reported that, half of all the meat eaten in the world is 

from pigs. In 1993, pork and poultry meat, according to FAO (2001) represented 63% 

of all meat consumed globally. In 2011, pork was reported to be the most popular meat 

consumed in the world, totaling 37% of all meat eaten and produced, some 109 million 

tons worldwide (McDermott, 2012).  

 

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In Ghana, among the livestock, pigs hold immediate to short term solution to animal 

protein deficiency (Annor-Frempong and Segbor, 1994) since they are able to 

efficiently convert feed into edible meat (Barnes, 1994) including a variety of crop 

waste, kitchen waste and agro-industrial by-products into high quality meat. 

Food from livestock and poultry such as milk, meat and eggs are rich in energy, 

protein, vitamins and micronutrients, which are particularly important in the diets of the 

most vulnerable groups, that is children, pregnant and breast feeding women.  In 

developing countries, malnutrition is common. However, meat, milk and eggs provide 

an important opportunity to overcome this problem (Perry et al., 2002).  

 

Pork can be processed into various forms including sausage as a form of preservation 

and value addition. FAO (2010) revealed that sausages are the most appetizing and 

widely utilized meat product among all processed meats, and are of many varieties 

depending upon mode of manufacturing. Fresh pork sausage comprises the vast 

majority of fresh sausage produced throughout the world, and can be in bulk, link, or 

patty form.  Fresh pork sausage is usually considered to be the third most popular 

processed meat product outranked only by wieners and bologna (Jay, 2011).   

 

Fresh sausages are normally made from selected cuts of fresh meat; they may contain 

water not exceeding 3% of the total ingredients in the product. They are not cured and 

have to be stored under refrigeration or frozen state prior to their consumption (Romans 

et al., 2001). Pork sausage can be manufactured from either chilled meat, trimmings 

from primal cuts or entire carcasses, or hot processed meat. To preserve the meat and 

improve the flavour of the product, salt is added and then flavoured with spices (FDA, 

2010). They are then stuffed into casings (natural or artificial) to make the product 

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more convenient to eat. Studies have indicated a number of spices including garlic, 

rosemary, clove, black paper, ginger, nutmeg, mace etc., which have been used in 

sausage making worldwide (FAO, 1985). The combination of spices depends on the 

taste, flavour, shelf life, colour among others, of the manufacturer. However, 

developing countries import most of these spices, which can be cultivated and 

processed for utilization.  

 

2.3 Some Selected Spices and their Characteristics 

The name spice is derived from the word species, which was applied to groups of 

exotic foodstuffs in the middle ages, DeeSpice Limited (DSL) (2014). Spices are dried 

seeds, flowers, fruits, barks, roots and leaves added to foods for the purposes of flavour, 

colour, or as preservatives and limit the rate of rancidity (Thomas, 2007 and FAO, 

2010).  Spices are mostly tropical plants or parts valued for providing colour and 

aromatic flavouring along with stimulating odour for use in cooking and in condiments, 

as well as in candies, cosmetics, fragrances and medications (DSL, 2014). The most 

important natural spices used in meat products are pepper, paprika, nutmeg, mace, 

cloves, ginger, cinnamon, cardamom, chilli, coriander, cumin and pimento (FAO, 

2010). Summary of the classification of natural spices based on the part used in food is 

shown in Appendix 2.   

 

2.3.1 Mace (Myristica fragrans) 

Mace, Myristica fragrans, is gotten from a tropical fruit known as nutmeg. Nutmeg is 

the seed of the tree, roughly egg-shaped and about 20 to 30 mm (0.8 to 1.2 in) long and 

15 to 18 mm (0.6 to 0.7 in) wide, and weighing between 5 and 10 g (0.2 and 0.4 oz) 

dried, while mace is the dried "lacy" reddish covering or aril of the seed Encyclopedia 

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http://en.wikipedia.org/wiki/Seed
http://en.wikipedia.org/wiki/Aril


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Britannica Online (EBO) (2014) ; Tropical Spice Garden (TSG) (2012). The tree is slow 

growing evergreen tree grows to more than 20 m and is cultivated in India, Ceylon, 

Malaysia, and Granada. Its fruit is called a drupe or a nutmeg apple, which is similar in 

appearance to a peach, or an apricot. The lacy aril is removed by hand from the outer 

shell of the nutmeg and then dried, becoming yellowish-brown mace, De La Grenada 

Industries Limited (DLG) (2009).  Mace is sold in whole pieces called blades or in the 

more commonly found ground form. As it is dried, it develops its characteristic aroma 

but loses its bright red colour. The colour can often help you determine its origin. 

Orange-yellow blades most likely come from Grenada, while   orange-red blades tend to 

be from Indonesia. Mace has a flavour described as a combination of 

cinnamon and pepper, a more pungent version of nutmeg. Unlike most spices, ground 

mace has a  longer shelf-life when stored properly in a tightly-sealed jar or container in a 

cool dark place, Cryogenically Processed food  (CPF) (2008). 

 

2.3.2 White Pepper (Piper nigrum) 

White pepper, sometimes known as pepper-corn is from the seed of the plant Piper 

nigrum, which flesh or rind has been removed before milling the seed, P.C Kannan & 

Co (PCK) (2012). Piper nigrum belong to the Piperaceae family, Germplasm 

Resources Information Network (GRIN) (1995). They are mostly found in countries 

like India and Indonesia. Pepper berries look like grapes and they produce pepper corns 

in three kinds: white, black and green. They are sold either whole or ground. Black 

peppers are the most popular kind and they have the strongest flavour. They are 

processed before the pepper berry is even ripened. Green pepper corns come from 

berries that become immature and the seeds are processed by preserving them in brine. 

And finally, white pepper is processed from really ripened pepper berries. White pepper 

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has a slightly different flavour from black pepper due to the high content of piperine. It 

is also milder but more pungent in taste than the black kind (GRIN, 1995). White 

pepper‟s flavour is sometimes described as piney. White peppers are often treated using 

chemicals and enhancers to make them whiter in colour and is mostly sprinkled on food 

to preserve the appearance. Among all the spices, white pepper is the commonly natural 

spice used in sausage making (FAO, 2010). Spices are mainly used in the ground form, 

which improves visual appearance of the meat product. The processed particle size 

(from 0.1 to 1 mm) of the spice determines the release and distribution of flavour 

(Ockerman and Basu, 2004). 

 

2.3.3 Onion (Allium cepa) 

The onion (Allium cepa), is also known as the bulb onion or common onion. It is used 

as a vegetable and is the most widely cultivated species of the genus Allium (Block, 

2010). The onion plant is a perennial herb growing to about 1.2 m in height, with 4 to 6 

hollow, cylindrical leaves. They are fleshy, hollow and cylindrical, with one flattened 

side. Onions contain 89% water, 1.5% protein, 2% fibre, 0.1%fat  and vitamins B1, B2, 

C, and folic acid along with potassium and selenium, National Onion Association 

(NOA) (2011). They are pungent when chopped and contain alliinase enzyme, which 

acts on the chemical alliin converting it into allicin, that irritates the eyes (Kuettner, 

2002). Onions are good source of fibre, and with only 45 calories per serving, and add 

abundant flavour to a wide variety of food.  

 

2.3.4 Marjoram (Origanum majorana) 

Marjoram is indigenous to Cyprus and Southern Turkey, it belongs to the Lamiaceae 

family (GRIN, 2012). Marjoram is cultivated for its aromatic leaves, which can be 

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steam-distilled to produce an essential oil. Marjoram can be used in seasoning soups, 

stews, dressings and sauce (Kains, 2007). Origanum majorana has exhibited some 

antimicrobial activities in vitro due to the presence of terpinen-4-ol (Busatta et al. 2008), 

marjoram reduced the count of E. coli in fresh sausages in vitro. It was concluded that 

marjoram could be used to prolong the shelf life of fresh sausages due to its 

bacteriostatic action at minimum inhibitory concentration (MIC) and its bacteriocidal 

action at higher concentrations ( 2010). 

 

2.3.5 Ginger (Zingiber officinale) 

Ginger is a herb but often known as a spice, from Zingiberaceae family. Ginger is 

indigenous to southern China, from whence it spread to other parts of Asia, and West 

Africa and to the Caribbean (Spices, 2002). It has a strong distinct flavour that can 

increase the production of saliva. It can be used fresh, dried and powdered, or as a juice 

or oil. The part that is used as spice on the plant itself is the rhizomes or ginger root. The 

ginger plant is approximately 30 – 60 cm tall and is extremely rare to find in the wild. 

Ginger produces clusters of white and pink flower buds that bloom into yellow flowers. 

Fresh ginger may be peeled before eating. Young ginger rhizomes are juicy and fleshy 

with a very mild taste. For longer-term storage, the ginger can be placed in a plastic bag 

and refrigerated or frozen. Ginger produces a hot, fragrant kitchen spice and acts as a 

useful food preservative. Ginger contains a very high level (3.85 mmol/100 g) of 

antioxidants (Halvorsen et al., 2002). About 115 bioactive constituents are found in both 

fresh and dried ginger varieties. Gingerols are the major constituents of fresh ginger and 

are found slightly reduced in dry ginger; whiles the concentrations of shogaols, which 

are the major gingerol dehydration products, are more abundant (Jolad et al., 2005). 

Several studies indicate that ginger suppresses lipid peroxidation and protects the levels 

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http://en.wikipedia.org/wiki/Zingiberaceae
http://en.wikipedia.org/wiki/Southern_China
http://en.wikipedia.org/wiki/Asia
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of reduced glutathione ( Reddy and Lokesh 1992; Ahmed et al., 2000a; Ahmed et al., 

2000b; Ahmed et al., 2008).  

2.3.6 Clove (Syzygium Gaertner) 

Clove belongs to the family Myrtaceae. The plant is economically important due to its 

essential oils with strong fragrances, which can be used in several ways. A well-known 

example is pimentum (Pimenta dioica). Clove was originally named Caryophyllus 

aromaticus by Linnaeus but later transferred to the genus Eugenia L. by Thunberg 

however, clove is now known as Syzygium Gaertner. A number of characters in flower 

and fruit distinguish the exclusively old-World genus Syzygium from Eugenia, which 

mainly encompasses new world taxa.  

 

Cloves thrive best with insular maritime climates in the tropics at low altitudes. In the 

original habitat in Moluccas, where the trees are semi-wild, annual rainfall is 218 – 355 

cm and temperatures 24 – 33 C. Drier weather is desirable for harvesting and drying the 

crop. According to Murty and Subrahmanyam (1989), deep, sandy, red and acidic-loams 

are the best soils. Good deep drainage is essential. The tree is slender and can reach up to 

15 m tall, conical when young, later becoming cylindrical, in cultivation usually smaller 

and branched from the base.  

 

The bark is grayish smooth and the wood of stem is hard but brittle (Purseglove, 1968). 

Clove contains a volatile oil, 14 to 20%; gallotannic acid, 10 to 30%; oleanolic acid, 

vannilin, eugenin and other extraneous materials associated with dried buds (Robbers et 

al., 1996). Clove is considered to be the most fragrant of all aromatic spices. Its flower 

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bud is mostly used as spice. Gustatory and sensory experts have described it to be 

“exquisitely scented, exhaling perfume rare and delicious”. The aroma of ground cloves 

has been characterized as being spicy, peppery, sweet, fruity, phenolic, woody and 

musty. According to Farell, (1990), the aroma of cloves has been characterized as warm, 

spicy, fruity, astringent, and slightly bitter with a warm numbing effect. Cloves are 

usually used for seasoning sausages, sauces, apple pudding and tarts. According to  Cai 

and Wu (1996) there is clear evidence that clove exhibits antibacterial activity against 

important oral pathogens and may therefore be an important prophylactic. Hot water 

extract of Syzygium aromaticum showed anti-cytomegalovirus (CMV) activity in vitro. 

When orally administered to mice, the activity of cytomegalovirus was also suppressed 

in the lungs (Yukawa et al., 1996). 

 

2.3.7 African Pepper (Xylopia aethiopica) 

Xylopia aethiopica, commonly known as african pepper, guinea pepper, Spice tree, 

ethiopian pepper belong to the family Annonaceae. It is locally known as, etso, soo, 

hwentia, chimba, kimba, (Ewe, Ga, Akan, Hausa and Dagbalin respectively) and 

consist of dried mature fruit and has characteristic odour and taste (Orwa et al., 2009). 

It is a slim, tall, evergreen, aromatic tree up to 15–30 m high and about 60–70 cm in 

diameter with straight stem, many-branched crown and sometimes buttressed. It often 

has short prop roots, smooth grey-brown bark and scented when fresh.  Its leaves are 

simple, alternate, oblong, elliptic to ovate, 8-16.5 by 2.8-6.5 cm, leathery, bluish-green 

and without hairs above, but with fine brownish hairs below, margin entire, and 

glabrous. Its petiole is about 0.3-0.6 cm, thickset and dark-coloured. Flowers of the tree 

are bisexual, solitary or in 3-5 flowered fasicles or in strange, sinuous, branched spikes, 

or cymes, up to 5.5 by 0.4 cm and creamy-green. The fruits of Xylopia aethiopica are 

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small with carpels of about 7-24, forming dense cluster. The fruits have dark brown 

colour when matured, cylindrical and are about 1.5-6 cm long and 4-7 mm thick (Tairu, 

et. al., 1999). The contours of the seeds are visible from outside.  

Extracts of the fruits, or decoction of the bark, have been reported to have wide ethno-

medicinal uses.  In Ivory Coast the fruit extract is used as tonic to encourage female 

fertility, for ease of childbirth and as a remedy for woman after childbirth (Burkill, 

1985). They are useful in the treatment of bronchitis and dysenteric conditions, and also 

as a medicine for biliousness and febrile pains.   

 

In Congo, the bark is steeped in palm-wine which is given for attacks of asthma, 

stomach-aches and rheumatism at the rate of one or two glasses per day (Acquaye et al., 

2001). The wood is resistant to termite attack and is used in hut-construction for posts, 

scantlings, roof-ridges and joists most especially in Togo and Gabon. It burns with a hot 

flame and has found use as a steamboat fuel. The root-wood can be used as a cork. The 

root is strongly aromatic and a concentrated root-decoction is used as a mouthwash for 

toothache in Africa (Burkill, 1985). The seeds, as separate from the fruit, are substitute 

for pepper, and have cosmetic, revulsive and stimulant uses.  

 

The powdered root is used as a dressing for sores and to rub on gums for pyorrhoea and 

in local treatment of cancer in Nigeria, and when mixed with salt is a cure for 

constipation. The dry fruits are an important spice used to prepare local dishes and soups 

in West Africa (Acquaye et al., 2001). The chemical constituents  of Xylopia aethiopica 

include essential oils, resins, annonacin, reberoside, avicien, rebersole, alkaloids, tannins, 

oxalate, and flavonoids (Ekeanyanwu and Etienajirhevwe, 2012). Xylopia aethiopica 

extracts demonstrated antimicrobial activity against gram positive and negative bacteria, 

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however, it has not been shown to be effective against E. coli (Iwu 1993). Xylopic acid 

has also demonstrated activity against the fungus Candida albicans (Acquaye et al., 

2001). 

2.3.8 The African Nutmeg (Monodora myristica) 

The African nutmeg (Monodora myristica), also known as calabash nutmeg belonging to 

the family Annonaceae or custard apple family of flowering plants (Okafor, 2003). It is 

locally known as awerewa, ayikue, ariwo (Akan, Ewe and Ga) etc. The tree grows 

naturally in evergreen forests from Liberia through Ghana, Nigeria and Cameroon, 

Angola and also Uganda and west Kenya. The tree can reach a height of 35 m and 2 m in 

diameter at breast height. Several studies reveal that almost every part of the tree is of 

economic importance (Okigbo and Igwe, 2007; Okafor, 1987). However, the most 

economically important part is the seed, which is embedded in a white sweet-smelling 

pulp of the sub-spherical fruit. The odour and taste of the Monodora myristica seed is 

similar to nutmeg. The kernel is a popular condiment used as a souring agent.  

 

When ground into powder, the kernel is used to prepare all kind of soups and as 

stimulant to relieve constipation and control passive uterine haemorrhage in women 

immediately after childbirth (Burubai, 2009). In addition, the essential oils extracted 

from the roots, seeds and stem barks of Monodora myristica is used to cure scabies, 

toothache, helminthiasis, malaria, dysenteric syndromes, constipation and as a stimulant 

(Talalaji, 1999; Irvine, 2000; Okpekon et al., 2004). The seeds contain 5-9% of a 

colourless essential oil. The major compounds found in the essential oil from the seeds 

are α-phellandrene, α-pinene, myrcene, limonene flavonoids, phenols, tannins, saponins 

and pinene. The plant‟s proximate composition ranged from 3.06 to 52.42% with 

nitrogen free extract having the highest value and ash content lowest (Ochuko, 2012). 

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Appendix 3 gives the detail of the proximate composition of Monodora myristica. 

According to Ogu et al. (2011) S. aureus, E. coli, P aeruginosa, B. cerus, P. 

mirabilis and C. albicans susceptibility to african nutmeg extracts‟ increased at 200 

mg/ml. The zone of inhibitions of Monodora myristica extracts against Escherichia coli 

was (11millimetre), Bacillus substilis (8millimetre) and Staphylococcus aureus 

(11millimeter) (Adewole et al., 2013). Monodora  myristica exhibited high antioxidant 

activities in vitro, signifying the protective potential of the spice against free radicals 

(Ochuko, 2012), and this may be attributed to phenolic and flavonoids content of the 

spice. According to Ochuko et al. (2012) phytochemicals screening of M.myristica 

revealed the presence of alkaloids, tannins, cardiac glycosides, steroids, terpenoids and 

saponins Appendix 3, which may contribute to its antioxidant activities. 

 

2.4. Uses of Spices 

 Spices are mainly used to improve the palatability/ taste and the visual appearance of 

diets. Spices piquant flavors stimulate salivation and promote digestion. They also 

improve the texture of some finished products. Spices, along with salt, in mixtures 

seem to preserve meats with a great taste. Pungent spices were useful for relieving the 

salty taste of such foods, Shiny Spices (SS) (2013). The aromatic spices such as 

cinnamon, cloves, mint etc. are used to disguise the foul breath from onion and garlic. 

In seasoning of meat and fish, spices enhanced the meat or fish flavour (SS, 2013).  A 

spice‟s flavour strength and quality are subject to variation depending on season, where 

and how it is grown, handling, transportation and processing (Ockerman and Basu, 

2004).  

The production process of Natural spices can also be a source of microorganisms‟ 

contamination in food (Ockerman and Basu, 2004; FAO, 2010). The most common 

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methods employed in decontaminating microbes on spices include radiation techniques 

such as gamma, electronic, UV or heating, microwave processing, exposure to steam 

and steam distillation and treatment with ethylene oxide gas or high-pressure 

processing. Most spices have antimicrobial and/or antioxidant properties, which served 

as food preservatives. The antimicrobial and antioxidant activities of plant essential oils 

is due to their chemical structure, in particular to the presence of hydrophilic functional 

groups, such as hydroxyl groups of phenolic components, flavanoids, terpenoids and 

lipophilicity of some essential oil components (Craig, 1999). 

 

‘Essential oils‟ (EOs) are volatile, odoriferous components that are present in many 

plants and are normally obtained by steam distillation (Ockerman and  Basu, 2004). 

The most components of EOs are hydrocarbons (terpenes, sequiterpenes), oxygenated 

compounds (alcohol, esters, aldehydes, ketones) and non-volatile residues (waxes, 

paraffin). Essential oils only contain part of the spice profile and are often deficient in 

bitterness, heat, sweetness, and other flavour components whiles oleoresins‟ are 

prepared from spices or herbs by extraction with organic solvents and contain both the 

volatile portion (essential oils) and the non -volatile extract, which includes resins. 

Oleoresins contain more complete flavour profile than essential oils. Both oleoresins 

and essential oils are microbiologically sterile and can be standardized for strength and 

flavour profile (Ockerman and Basu, 2004). 

 

2.4.1 Flavour Enhancer 

Flavourants are agents that are intentionally added to food with the sole intention of 

imparting flavour. There are several different categories of flavouring agents such as 

smoke flavours and process flavourings (European Commission, 1988). Flavouring 

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substances are organic volatile  chemicals, with a molecular weight not exceeding 300 

g/mol and composed of carbon, hydrogen, often oxygen and sometimes nitrogen or 

sulphur but never any other element unless the substances are salts with common 

physiological cations or anions. 

 

2.4.2 Antimicrobial Properties of Spices  

Comminuted processed meat such as sausages contain meat and fat as major 

ingredients. This provides a medium for spoilage microbial growth and fat 

deterioration, which affect both shelf life and organoleptic quality of the product. Shelf 

life is a guide for the consumer of the period of time that food can be kept either under 

refrigeration or under room temperature before it starts to deteriorate, provided all 

storage conditions have been followed (Microchem, 2007). The shelf life of a product 

begins from the time the food is produced. According to New Zealand Food Safety 

Authority (NZFSA) (2005), shelf life duration is dependent on many factors such as the 

types of ingredients, processing, type of packaging and how the food is stored. The 

technology employed in sausage production is said to affect the type of microbial 

contamination, which might gain access into the sausage from either the meat or the 

natural casing or the spices and other non-meat ingredients. In addition, production 

handling/poor personal hygiene, poor environment and equipment also serve as sources 

of microbial contamination. It is therefore important to incorporate preservative agents 

into meat products to control microbial spoilage and oxidation of fat. 

Additionally, the use of spices as preservation technique reduces the use of chemical 

food additives such as nitrite and salt in meat products. Meat products are normally 

preserved by heat treatment to 75 °C in the product, thereby eliminating all the live 

microbes in the product.  Products that are not heat-treated to 75 °C, the growth 

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inhibition are achieved by low pH value obtained by fermentation with lactic acid 

bacteria in combination with a rather high amount of salts (for instance salami, pepperoni 

etc.). However, excessive intake of salt correlated with increased risk of coronary heart 

diseases and an increased high blood pressure Consensus Action on Salt and Health  

(CASH)  (2008). This has led consumers to perceive natural antimicrobial preservatives 

as a healthier alternative to synthetic antimicrobial preservatives.  

 

Research from the 1940's to late 1970's created the concerns that consuming food treated 

with nitrate and nitrite could have adverse effect on human health and at times death .In 

response, meat processors began utilizing natural nitrate sources such as celery powder 

and many more (Gary, 2011). Spices are often strong, zesty, pungent, fiery and fragrant, 

giving a dish an exotic and exciting taste and play a major role in culinology, as they are 

versatile in feature (Rathore and Shekhawat, 2008). More importantly, most spices 

contain dozens of secondary compounds and these chemical compounds help to protect 

them against herbivorous, insects and vertebrates, fungi, pathogens, and parasites 

(Walker, 1994). Some animals that store food often add plants with antibacterial and 

antifungal properties to their caches e.g., brown bears sometimes cover carcasses with 

Spaghnum moss (Elgmork, 1982). Addtionally, onion has been used to prevent the 

growth of oral pathogenic bacteria, including Streptococcus mutans, Porphyromonas 

gingivalis, and Prevotella intermedia organisms associated with dental caries and 

periodontitis (Sarika and Shikha, 2014). The antimicrobial ability of onion is associated 

with a number of sulfur containing compounds such as alliin, allylalliin, diallyl disulfide 

and the methyl and propyl compounds of cysteine sulfoxide Natural Resources 

Conservation Services (NRCS) (2007).  Onion oil also inhibited growth of other gram-

positive bacteria and gram-negative bacteria such as Klebsiella pneumoniae.  Antifungal 

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actions of onion include inhibition of yeasts and a number of molds (Sarika and Shikha, 

2014).   Garlic extracts have demonstrated antifungal activity when tested in vitro 

suggesting a potential use in the treatment of oral and vaginal candidiasis. Several 

studies revealed garlic possessed wide spectrum of antibacterial, antiviral, antifungal and 

antiprotozoal activities and also for its medical benefits on the immune and 

cardiovascular systems (Sallam et al., 2004). Garlic oil and oregano were effective 

against species such as S. aureus, S. enteritidis ,L. monocytogenes, E. coli and L. 

plantarum in whey protein-based film (Coma, 2008). According to Martinez et al. 

(2007), fresh garlic and the powder has been shown to maintain aerobic plate 

count in chicken sausage below the maximum permissible limit (MPL) stored at 

3 °C (MPL is 7 log10 cfu/g).  At 30 g/kg and 9 g/kg, fresh garlic and powder garlic 

produced significant antimicrobial and antioxidant effects and extended the shelf life of 

chicken sausage up to 21 days (Sallam et al., 2004).  

 

According to Matan et al. (2006), the combination of cinnamon and clove oils suppresses 

the growth of major spoilage microorganisms of intermediate-moisture foods. The 

eugenol in clove oil has shown a strong inhibition effect on the growth of Listeria 

monocytogenes, Salmonella enteritidis, Escherichia coli and Staphylococcus aureus in 

various agar mediums (Mytle et al., 2006). At about 2000 μg/ml, ginger had shown 

minimum inhibitory concentration (MIC) effect against Clostridium botulinum.  

 

The EOs in ginger (gingerone and gingerol) showed inhibitory effect against both 

cholera and typhoid bacteria (Hirasa and Takemasa, 1998). Gingerols has shown other 

antimicrobial properties against B. subtilis and E. coli (Yamada et al., 1992) 

and Mycobacterium (Galal, 1996). Enterocin production by Enterococcus faecium CTC 

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492 was strongly reduced when black pepper was added to the fermentation medium 

(Aymerich et al., 2000). Spices such as oregano, rosemary, thyme, sage, basil, turmeric, 

ginger, garlic, nutmeg, clove, mace, savory, and fennel, have been successfully used 

alone or in combination with other methods of food preservation. They either exert direct 

or indirect effects to extend food product shelf life or as antimicrobial agent against a 

variety of Gram positive and Gram-negative bacteria. Meanwhile, their efficacy depends 

on the pH, the storage temperature, the amount of oxygen, the EO concentration and 

active components (Gutierrez et al., 2008a; Sandasi, et al., 2008; Viuda-Martos, et al., 

2008).  

 

Terpenes, carvacrol, p-cymene, and thymol, are the active compounds in oregano, savory 

and thyme that have demonstrated antifungal and antimicrobial activity that has attracted 

attention recently because of their potential food safety applications, especially for 

oregano (Bendahou et al., 2008). The five most common antimicrobial compounds are  

a-Pinene, cineole, limonene, linalool and geranyl acetate that have been effective against 

some food-borne pathogens and antibiotic-resistant Staphylococcus aureus, Bacillus 

cereus, Escherichia coli and Campylobacter jejuni (Chen et al., 2008; Sandasi et al., 

2008). According to Bañón et al. (2007), at a maximal tolerated concentration (MTC), 

grape seed extract exhibits a high antioxidant activity in fish oil and frozen fish, cooked 

pork patties and cooked turkey. 

 

2.4.3. Antioxidant Activity of Spices 

Antioxidants are substances that at low concentrations retard/inhibit the oxidation of 

easily oxidizable biomolecules, such as lipids and proteins in meat products, thus 

improving shelf life of products by protecting them against deterioration caused by 

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oxidation (Liz and Getty, 2012). According to Pavana et al. (2009), antioxidants protect 

the body against adverse effects of generated reactive oxygen species, which possess the 

ability to cause oxidative damage to the human body. Oxidation of lipid is influenced by 

the composition of phospholipids, the amount of polyunsaturated fatty acids, the 

presence of metal ions, oxygen, haem pigments, mechanical processes, and salt addition 

to product during processing. Lipid oxidation occurs when polyunsaturated fatty acids 

react with molecular oxygen via free radical chain mechanism forming peroxides 

(Devatkal et al., 2010). 

 

Oxidation of lipid is one of the major causes of food quality deterioration, and has  

economic importance (Raghavan and Richards, 2007) as it can negatively affect sensory 

attributes such as colour, texture, odour and flavour as well as the nutritional quality of 

the product (Nunez de Gonzalez et al., 2008).  Antioxidants play major role in food 

preservation due to their ability to prevent oxidative deterioration of lipids (Ademiluyi 

and Oboh, 2008) and this has led to the use of synthetic antioxidants such as butylated 

hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tert-butylhydroquinone 

(TBHQ), and propyl gallate (PG) (Jayathilakan et al., 2007), as antioxidants in meat 

products. These synthetic antioxidants have fallen under serious scrutiny due to their 

potential toxicological effects (Naveena et al., 2008; Nunez de Gonzalez et al., 2008). As 

a result, the meat industry is in a need of economical and effective natural antioxidants 

that can replace synthetic antioxidants without any negative effect on finished products 

quality and consumer perceptions on health. Several studies have focused on  

identification of novel antimicrobial and antioxidants from natural sources. This is 

mainly due to their high content of phenolic compounds, which make plant materials a 

good source of natural antioxidants providing an alternative to currently used 

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conventional antioxidants (Sanchen-Moreno, 2002; Nunez de Gonzalez et al., 2008). 

Natural antioxidants such as rosemary and spice extracts have been reported to be more 

active than synthetic antioxidants. According to Schuler (1990), antioxidants properties 

of certain ground spices stabilized fat in food products. The carnosic acid in rosemary 

has been described as the most active antioxidant constituents (Brieskorrn and Domling, 

1969). Antioxidant extract from rosemary are commercially available in fine powder 

forms. Depending on the active content of antioxidant extract from plants, the 

recommended levels range between 200 and 1000mg/Kg of finished product (Schuler 

1990).  

 

The European Union in 2010 authorized the use of rosemary extracts as new food 

additives to be used in foodstuffs under Directive 95/2/EC and assigned E 392 as its E 

number (European Union directives 2010/67/EU and 2010/69/EU). This approval of 

carnosic acid and carnosol rated rosemary extract as a safe natural alternative to synthetic 

antioxidants. Garlic extracts have also shown antioxidant activity in different in vitro 

models. The antioxidant activity of Allium spp. bulbs has been attributed to a variety of 

sulphur-containing compounds and their precursors (Aarni et al., 2003). Curry leaf 

extracts which contain monoterpene derived hydrocarbons and alcohols have been 

recognized for their antioxidant efficacy in foods (Ningappa et al., 2008 ). Bali et al. 

(2011) indicated that coriander treated samples exhibited better antioxidant property 

where as garlic treated samples showed a better antimicrobial property. 

 

2.4.4. Medicinal Properties of Spices 

Spices were believed to improve health, since it was understood that they could affect the 

four humours (blood, phlegm, yellow bile and black bile) and influence the 

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corresponding moods (sanguine, phlegmatic, choleric and melancholic). Ginger is used 

to heat the stomach and improve digestion; clove is believed to comfort the sinews; mace 

helps to prevent colic and bloody fluxes or diarrhea; nutmeg help relieve any bad cold. A 

15% tincture of cloves is effective in treating topical fungal, ringworm infection (Sarika 

and Shikha, 2014). Cinnamon oil has been used to combat microorganisms, 

diarrhea and other GI disorders, and dysmenorrhea.  

 

According to Saudi (2008) ginger has a significant lipid lowering effect on patients with 

hyperlipidemia. The aromatic EOs of five plants (Eucalyptus citriodora, Eucalyptus 

globulus, Mentha piperita, Origanum syriacum, and Rosmarinus officinalis) combined 

on patients with upper respiratory tract infections were relived on day six (Eran et al., 

2011). Ten milligrams of dried oregano leaves administered as an oral solution to calves 

with diarrhoea was effective in the treatment of colibacillosis as neomycin (Bampidis et 

al.,2005).  

 

Turmeric is used to cure cancer as it has anti-cancer agents known as curcumin. It kills 

bacterial and reduces fungus growth at concentrations >100 µM (Lüer et al., 2010). 

Curcumin which gives turmeric its yellow color, help people fight off or prevent diseases 

such as diabetes and cancer (Sundaram, 2005). Mace has been used extensively in 

treatment of wide range of ailments such as digestive disorder, rheumatism, cholera and 

flatulence (Shibamoto and Bjedanes, 1993).  Tea and grape seed extracts have been 

suggested to add neutraceutical and health benefits (Jayaprakasha et al., 2003). 

 

University of Ghana http://ugspace.ug.edu.gh

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26 

 

2.5 Microbial Composition of Fresh Sausage 

Meat generally is a nutrient-dense medium ideal for growth of a wide range of 

microorganisms (Garbutt, 1997; Russo et al., 2006; Zhang et al., 2009) especially 

comminuted meat, which possesses a large surface area for easy contamination during 

the mixing or mincing operation, American Meat Institute Foundation (AMIF) (1997). 

The major types of these microorganisms found in meat and meat products are bacteria, 

yeasts and moulds. Garbutt (1997) and Huffman (2002), studies showed that the 

composition of meat microbiota associated with spoilage of fresh meat includes 

Enterobacteriaceae, lactobacilli, pseudomonas, Brochothrix thermosphacta and 

Shewanella putrefaciens.  

 

Spoilage microorganisms can readily grow in both fresh and precooked meat products, 

rendering the product inedible and unattractive by destroying the colour, flavour and 

structure. Surface spoilage of sausages may be influenced by high moisture content, and 

is normally shown by the appearance of slime, due to excessive bacterial proliferation, or 

by an abundant greyish-white growth of mould (FAO, 2010). Food and meat products 

can be categorised as perishable, semi-perishable and stable or non-perishable products 

(Madigan et al., 2003). Fresh sausages have been categorised as perishable food products 

due to their high water activity and pH (Romans et al., 2001; Cocolin et al., 2004). 

Spoilage occurring in the interior portion of the sausage is usually due to adverse effect 

of unhygienic production conditions as well as poor hygienic quality of processed raw 

materials. According to Borch and Nerbrink (1989); Dykes et al. (1994); Dykes and Von 

Holy (1993);  Korkeala and Mäkelä (1989), great diversity of lactic acid bacteria can be 

found in different types of spoiled cooked sausages. 

 

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2.5.1 Spoilage Bacteria 

The microbial composition of meat and meat products may depend mainly on the kind of 

environment, the type of meat and raw materials, equipment, packaging materials and 

storage temperature (Sachindra et al., 2005). Carcass can be contaminated with bacteria 

from the water, air and the soil as well as from the faeces and the intestine of animals, the 

workers, and the equipment used during the manufacturing process, after slaughtering 

(Sachindra et al., 2005). Microbial spoilage is the most common cause of spoilage, and it 

is visible through the growth of colonies and slime, textural changes (degradation of 

polymers) or as development of off-flavours. According to Cocolin et al. (2004), 

microbial profiles of fresh sausage are characterized by the presence of aerobic, 

facultative anaerobic and mesophilic bacteria, which cause spoilage and food poisoning. 

The count range of aerobic colonies range from 1.5 x 10
3
 – 2.1 x 10

8
 cfu/g for fresh 

sausage and for frozen sausage from 1.4 x 10
3
 – 3.1 x 10

7
 cfu/g (Farber et al., 1988). 

 

 One of the hygiene indicators of meat and meat products is the presence of 

Enterobacteriaceae. According to Crowley et al. (2005), the presence of 

Enterobacteriaceae on processed meats is better indicator of poorly treated or post-

process contamination from the environment than coliforms since it is a direct indicator 

of the extent of faecal contamination. High number of E. coli present in meat and meat 

products is an indication of the presence of organisms of faecal origin. Nel et al. (2004) 

suggested that the maximum limit of E. coli in meat and meat products such as sausage 

should not be more than 10 cfu/g. As carcasses are moved into the chill room at near 

0
o
C, a selective environment is developed that favours growth of psychrophilic 

microorganisms such as Pseudomonas, Moraxella and Acinetobacter; the three; most 

dominant genera of pscychrotrophic microbes of soil origin. They are gram negative, 

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strictly aerobic rods that are able to grow at 0
o
C and even slightly lower.  Pseudomonas 

spps. causes spoilage of meat and meat products stored at low temperatures (Ercolini et 

al. 2007; Olofsson et al., 2007). Pseudomonas fragi is the most dominating specie of 

Pseudomonas that causes spoilage of meat stored in a refrigerator (8ºC or lower), 

followed by Pseudomonas lundensis and Pseudomonas fluorescens (Olofsson et al., 

2007). Pseudomonas strains grow rapidly and will predominate if chilled moist meat is 

held longer. The growth of Pseudomonas spp, is affected by oxygen tension, salt, water 

activity (aw ) and pH. Pseudomonas produces proteases and lipases which can catalyze 

reactions causing degradation of protein and fat during their growth period. They 

produce malodorous substances (esters, sulphides, acids) from amino acids metabolism 

(Pittard et al., 1982). 

 

2.5.2 Food –Borne Pathogens. 

The leading causes of illness and death in less developed countries are food borne 

pathogens, killing approximately 1.8 million people annually. (Sheng-Quan et al., 2009). 

Most comminuted meat products are full of many types of pathogenic microbes such as 

Salmonella spp., S. aureus, Listeria monocytogenes, E. coli and Campylobacter jejuni 

(Eisel et al., 1997).  Escherichia coli serotype O157:H7 is a gram-negative, rod-shaped 

bacterium. The "O" refers to the cell wall antigen serological classification, whereas the 

"H" refers to the flagellar antigen (James and James, 1998). It is frequently detected in 

the intestinal tracts and hide of cattle and pigs (Mathenjwa, 2010). It can be transmitted 

through consumption of contaminated food and water with faecal matter. (Li and Logue, 

2005; Arthur et al., 2008; Ateba and Bezuidenhout, 2008; Wong et al., 2009).  E. coli 

O157 outbreak was attributed to undercooked ground beef patties sold from a fast-food 

restaurant, which have seen E. coli O157 and became broadly recognized as an important 

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http://en.wikipedia.org/wiki/Serotype
http://en.wikipedia.org/wiki/Gram-negative
http://en.wikipedia.org/wiki/Flagellum


29 

 

human pathogen (Bell et al., 1994). Enterobacteriaceae are aerobes or facultative 

anaerobes that ferment a wide range of carbohydrates, possess a complex antigenic 

structure and produce a variety of toxins and other virulence factors (Sharma and 

Adlakha, 1996).  They are a large heterogeneous group of Gram-negative rods flora of 

the large intestinal tract of both humans and animals. The family includes genera 

Escherichia, Shigella, Salmonella, Enterobacter, Klelosiella, etc.  

 

A study conducted by Sharma and Adlakha (1996) shows that fecal coliforms are 

bacteria that ferment lactose to produce acid and gas at 44.5 
o
 C up to 48 hours and hence 

produce bad odours. Staphylococcus aureus belongs to the phylum Firmicute, and is  

commonly found in the respiratory tract and on the skin of both human and animals. It is 

a facultative anaerobic Gram-positive coccal bacterium, also known as "golden staph" 

and Oro staphira (Kluytmans et al., 1997). These bacteria are present in 20 to 30 percent 

of healthy people and are even more common among those with skin, eye, nose, or throat 

infections (Ford and Paula, 2005). This species is relatively tolerant to salt, which is 

found in some cured meat products as an essential selective medium for its growth when 

the moist cut surface is contaminated (Price and Schweigert, 1987). Staphylococcus 

aureus can grow extensively and produce the heat-stable enterotoxin without any 

resultant off flavours or odours. It is a common cause of skin infections (example boils), 

respiratory disease (example sinusitis), and food poisoning. The species can grow at a 

lower pH aerobically than anaerobically (Price and Schweigert, 1987). A study 

conducted by Barber and Deibel (1972) observed this growth characteristic in some 

fermented sausages. 

 

University of Ghana http://ugspace.ug.edu.gh

http://www.ncbi.nlm.nih.gov/books/NBK114501/#appa.r627
http://en.wikipedia.org/wiki/Firmicutes
http://en.wikipedia.org/wiki/Facultative_anaerobic_organism
http://en.wikipedia.org/wiki/Gram-positive
http://en.wikipedia.org/wiki/Coccus
http://en.wikipedia.org/wiki/Bacterium
http://en.wikipedia.org/wiki/Boils
http://en.wikipedia.org/wiki/Sinusitis
http://en.wikipedia.org/wiki/Food_poisoning


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2.6 Factors Influencing Shelf Life of Sausages 

Spoilage of food is generally influenced by environmental factors such as the food 

matrix, microbial characteristics, and water activity (aw), temperature, pH, processing 

time, processing technology, etc. Sausages have high water activity and high 

concentrations of readily available nutrients that made them susceptible to microbial 

growth, leading to development of off-odours, off-tastes and changes in texture and 

slime formation (Xiang and Holley, 2012). Intrinsic factors are factors that are 

characteristic of the food itself such as pH and free moisture and extrinsic factors are 

those that relate to the environment surrounding the food such as temperature and storage 

atmosphere (FDA, 2013).  

 

Generally meat and meat products spoilage is characterized by, (i) bacterial growth and 

metabolism causing formation of objectionable compounds, such as off-odours, gas, and 

slime, and (ii) lipids and pigments oxidation causing undesirable flavours and 

discolouration (Xiang and Holley, 2012). The numbers of microorganisms on fresh meat 

surfaces during chill storage change their typical growth pattern (Garcia-Lopez et al., 

1998) in response to temperature, pH, and available oxygen. However, only around 10% 

of these initial bacteria present are capable of growth during refrigeration storage of 

meat. Usually the nature and extent of surface contamination of meat determines its 

potential shelf life. 

 

2.6.1 Effect of Moisture Content of Spices on Shelf life Meat Product  

Water activity is the ratio of water vapour pressure of the food substrate to the vapour 

pressure of pure water at the same temperature (Jay, 2000);  (aw = p/po, where p = vapour 

pressure of the solution and po = vapour pressure of the solvent (usually water). The 

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aw of pure water is 1.00 and the aw of a completely dehydrated food is 0.00 (FDA, 2013). 

The aw of a food on scale from 0.00 - 1.00 is related to the equilibrium relative humidity 

above the food on a scale of 0 - 100%. Thus, percentage Equilibrium Relative Humidity 

(ERH) = aw x 100. The aw of a food describes the degree to which water is "bound" in the 

food, its availability to participate in biochemical reactions, and its availability to 

facilitate growth of microorganisms (FDA, 2013).  

 

The water activity of a food is a measure of its ability to support the growth of food 

spoilage microbes. Foods that are fresh have aw values that are close to the optimum 

growth level of most microbes (0.97 - 0.99) such as fresh meat, fresh sausages, 

vegetables and fruits. Water activity has a decisive influence on the growth of microbes 

in food (Claudio, 2008 ; FAO, 2010). The amount of water in sausages has a direct effect 

on microbial, chemical and enzymatic reactions (FAO, 2010). The aw-value of lean meat 

is about 0.99. In traditional sausage making, aw is reduced by drying or by addition of 

curing salts, non-ionic solutes, such as sugar, spices and different food additives 

(Claudio, 2008; FAO, 2010).  The aw-value can be influenced by appropriate formulation 

of the sausages as well as by manufacturing methods. For instance, water, fat and salt 

contents directly influence aw-value of  sausage Thus,  one percent level of fat added to 

the formulation will reduce the aw-value by 0.00045 and one percent of sodium chloride 

will also reduce the aw-value by about 0.0060 while one percent of sugar and that of soy 

or milk protein will reduce the aw-value by about 0.0020–0.0025 and 0.0012–0.0013 

respectively (FAO, 2010).  The optimum and minimum levels of aw for microbial growth 

depends on several growth factors in their environments, such as cell wall characteristics 

of microbes which determine their sensitive to low aw.  For instance, Gram negative 

bacteria generally are more sensitive to low aw than Gram positive bacteria (FDA, 2013). 

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Many bacterial pathogens growth can be controlled at water activities below 0.86 and 

only S. aureus can grow and produce toxin below aw 0.90. Multiplication of bacteria and 

yeasts is basically stopped at aw-values lower than 0.88 to 0.90 (FAO, 2010; FDA, 2013).  

 

Water activity influences deteriorative chemical reaction rate as water acts as a solvent; it 

can be a reactant on itself or can change the mobility of reactant through viscosity. Any 

one or a combination of any of these factors can lead to faster deterioration and 

shortened product shelf life AquaLab University (ALU) (ALU, 2014).  

 

2.6.2 Influence of Nutrient Source on Microbial Growth 

Microorganisms need basic nutrients for their growth and maintenance of metabolic 

functions. The type and amount of nutrients needed depends greatly on the 

microorganism. These nutrients include water, a source of energy, nitrogen, vitamins, 

and minerals (Mossel et al., 1995; Ray, 1996; Jay, 2000). Meats have abundant protein, 

lipids, minerals, vitamins and low levels of carbohydrates (Cross and Overby, 1998).  

Some bacteria metabolize more carbohydrates that are complex such as glycogen found 

in muscle foods and others can also use fats as an energy source (FDA, 2013).   

 

Gram positive bacteria are generally more fastidious in their nutritional requirements; 

therefore, they are not able to synthesize certain nutrients required for their growth (Jay, 

2000). S. aureus  is one of the gram positive food borne pathogen that requires amino 

acids, thiamine and nicotinic acid for growth. However, the gram negative bacteria 

generally, are able to derive their basic nutritional requirements from the existing 

carbohydrates, proteins, lipids, minerals, and vitamins that are found in a wide range of 

food (Jay, 2000).  Salmonella enteritidis is one example of food borne pathogens with 

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specific nutrient requirements. The availability of iron may limit the growth 

of Salmonella enteritidis. Thus, the availability of essential nutrients limits the rate of 

microbial growth in foods. 

 

2.6.3 pH and Acidity 

pH is a function of the hydrogen ion concentration in the food: pH = -log10 [H+].  Many 

bacterial pathogens grow best at pH values near neutral (i.e., 6.6-7.5) (Jay, 2000). It is a 

common method used to extend the shelf life of products. At a low pH values growth of 

foodborne pathogens bacterial can be inhibited and in some cases kill such pathogens. 

Acidity is a key factor affecting the growth and survival of microorganisms in food.    

A food‟s ability to support the growth and survival of spoilage pathogens is influenced 

by its pH. The pH of food products vary with time due to microbial activity and product 

formulations. The pH range for microbial growth and survival is determined by a 

minimum and maximum value with an ideal pH for optimum growth and survival. Most 

microbes grow best at or near a neutral pH value. A pH value of 4.6 or less is important 

in food processing as it prevents Clostridium botulinum from producing toxins and is the 

basis for commercial sterilization in low and intermediate acid foods Food Safety 

Authority of Ireland (FSAI) (2011). 

 

 2.6.4 Temperature 

Temperature is an extrinsic key factor affecting growth of food borne pathogens. Meat 

and meat products require low storage temperatures to retard the growth of 

microorganisms between -1 to +4°C by chilling or between -18 to -30°C freezing (FAO, 

2010). Meats meant for sausage processing can be processed at these temperatures to  

inhibit bacterial growth. All microbes have a defined temperature growth range, thus a 

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minimum, maximum, and optimum. Temperature has an adverse effect on both the 

generation time of an organism and its lag period; the growth rate of an organism is 

defined as an Arrhenius relationship (Mossel et al., 1995). There are four major groups 

of microorganisms that have been described based on their temperature ranges for 

growth: thermophiles, mesophiles, psychrophiles and psychrotrophs, International 

Commission on Microbiological Specification for Foods (ICMSF) (1980). The lag phase 

and growth rate of a microorganism are influenced not only by temperature but by other 

intrinsic and extrinsic factors such as pH, aw and time. 

 

2.6.5 Impact of Time 

Time is another critical extrinsic factor concerning the growth rate of microbial 

pathogens in food (FDA, 2013). Food producers address the concept of time as it relates 

to microbial growth when a product's shelf life is determined. Time can be used under 

certain circumstances at given ambient temperatures to control product safety. This can 

be achieved when the duration is equal to or less than the exponential phase of the 

pathogen(s) of concern in the product.  The lag phase for growth of L. monocytogenes at 

10 °C (50 °F) is 1.5 d, while at 1 °C lag phase is ~3.3 d. Likewise, at 10 °C the 

generation time for the same organism is 5-8 h, while at 1 °C (34 °F), the generation time 

is between 62 and 131 h (Mossel and Thomas, 1988). Time and temperature are integral, 

when considering growth rate of microbial pathogens in food. 

 

 

 

 

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CHAPTER THREE 

MATERIALS AND METHODS 

3.1. The Study Area 

The study was conducted at the Meat Science Laboratory and Microbiological 

Laboratory of the Animal Science Department of the College of Basic and Applied 

Sciences (CBAS) University of Ghana, Legon. 

 

3.1.1 Experimental Design  

The experiment was a factorial design with sixteen treatments (control-clove, onion, 

white pepper, and nutmeg, African pepper (AP), African nutmeg (AN) and  mixture of 

AP and AN) at 4 inclusion levels (0%, 0.05%, 0.1% and 0.15% of the meat weight) 

Appendix 4. There were three replicates. Products were evaluated for the effect of the 

spice mix on sensory attributes and microbiological load of fresh pork sausage. 

 

3.2. Preparation of African Nutmeg (AN) and African Pepper (AP) 

African nutmeg and African pepper were obtained from the local market in Accra. The 

spices were cleaned and washed thoroughly under running tap water and sundried. The 

dried African nutmeg (AN) were cracked manually to extract the kernels. The kernels 

were blended and stored in Ziploc bags under a room temperature. The seeds of the 

African pepper (AP) were blended with the pods and stored into Ziploc bags under room 

temperature. Both spices were sieved with a fine net. The spices were irradiated with a 

dose of 10 KGY at the Ghana Atomic Energy Commission  (GAEC) Irradiation Centre.  

The scientific name and origin of the selected local spices are presented in Appendix 5. 

 

 

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3.2.1 Sausage Preparation 

Fresh whole pork carcass was obtained from the Livestock and Poultry Research Center 

(LIPREC) University farm and stored under refrigeration conditions (4°C) overnight. 

The carcass was cut up and deboned and the sausages formulated, after using 80% lean 

and 20% fat. The meat was comminuted using a table-top mincer through 5mm steel 

plate (Model Talleres Ramon, Spain). The comminuted meat was manually mixed 

thoroughly in a mixing bowl. The mixture was divided into 16 equal batches by weight 

and treatment assigned to the batches randomly. The respective spice mixes and water 

(Appendix 4) were added and mixed manually (50 times). The sausage mixture was 

stuffed into a natural casing using manual stuffer and linked into 15cm length.   The 

products were bagged into Ziploc bags and sealed labeled and kept under freezing 

temperature (-10
oc) prior to sensory and microbial analysis. 

 

3.2.2. Sensory Evaluation  

Ten panelists were screened for sensitivity to fishy and cardboard flavours using a nine 

two-fold dilutions of exudates from fresh tilapia and 10g of cardboard boiled in distilled 

water for 1 hr. Each set of flavour profile was provided with a distilled water control. 

The panelists were also screened for crumbliness and juiciness. Consequently, six 

panelists made up of 4 females and 2 males were short-listed to participate in the sensory 

evaluation. The samples were grilled (Electrical grill) separately based on treatments to 

an internal temperature of 71
o 

C, for 45 minutes. The grilled sausages were sliced into 

uniform sizes approximately 15 g; randomly assigned labels and packed into respective 

coded 30ml containers and covered. The evaluation of the inclusion levels of the selected 

local spices was done by the use of a 15-point scale (Appendix 6) to evaluate 

crumbliness, juiciness, palatability, saltiness, off flavour and overall liking of the fresh 

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pork sausage.  Water and apple juice were provided to rinse off lingering odours after 

every sample.  

 

3.3 Plate Counts 

Sausage sample (1g) taken from the mid section was homogenized in 10 ml of distilled 

water using a blender. The homogenate was serially diluted (10
 -3

 and 10 
-4

), plated on 

nutrient agar (aerobic plate count-APC) in triplicates and incubated at 37
o 

C for 24 hours 

(Oluwafemi and Simisaye, 2006) to determine total viable counts. The same procedure 

was repeated for enterobacteriaceae count and E. coli / Coliform selective agar was used. 

The microbial assay were evaluated for respective treatments stored for day 0, 3 and 6 at 

4
o
C for all the three replicates. 

 

3.4 Statistical Analysis 

The microbial counts obtained from total bacteria, E. coli and coliform for each 

treatment was transformed to log cfu/g. The transformed values as well as results for 

sensory data were subjected to analysis of variance using proc mixed of SAS 9.1 (SAS 

Institute, Cary, NC, USA). SAS syntax for analysis (Appendix 7 and 8) are indicated. 

Probability differences between means were compared using bonferroni multiple 

comparison adjustment. Differences were considered significant at the p  ˃0.05 level at 

0.5. 

 

 

 

 

 

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CHAPTER FOUR 

RESULTS 

4.1. Sensory Evaluation 

Results of evaluated fresh pork sausages treated with varying levels of AP and AN on a 

15-point scale for crumbliness, juiciness, palatability, saltiness, off flavour and overall 

liking. Results for crumbliness and juiciness are shown in Table 1. Inclusion levels of 

AN (0.05 %), and AP*AN (0.05*0.05%)  

 

Table 1. Mean Crumbliness and Juiciness  

  Crumbliness   Juiciness 

Treatment Mean SEM 
 

  Mean SEM 
 

Control 8.2 ±0.6 
  

6.6 ±0.74 
 

AN (0.05%) 8.9 ±0.6 
  

6.2 ±0.74 
 

AN (0.1%) 8.3 ±0.61 
  

6.4 ±0.74 
 

AN (0.15%) 8.4 ±0.6 
  

6.6 ±0.74 
 

AP (0.05%) 8.6 ±0.59 
  

6.2 ±0.74 
 

AP (0.1%) 8.4 ±0.59 
  

6.6 ±0.74 
 

AP (0.15%) 8.7 ±0.59 
  

6.3 ±0.74 
 

AP*AN (0.05*0.05%) 8.9 ±0.6 
  

6.9 ±0.74 
 

AP*AN (0.05*0.1%) 8.7 ±0.59 
  

6.8 ±0.74 
 

AP*AN (0.05*0.15%) 7.9 ±0.59 
  

6.7 ±0.74 
 

AP*AN (0.1*0.05%) 7.9 ±0.6 
  

7.6 ±0.74 
 

AP*AN (0.1*0.1%) 8.0 ±0.59 
  

6.8 ±0.74 
 

AP*AN (0.1*0.15%) 8.6 ±0.6 
  

7.6 ±0.74 
 

AP*AN (0.15*0.05%) 8.1 ±0.59 
  

6.7 ±0.74 
 

AP*AN (0.15*0.1%) 8.4 ±0.6 
  

5.9 ±0.74 
 

AP*AN (0.15*0.15%) 7.8 ±0.59 
  

6.1 ±0.74 
 

P-value 0.62 
   

0.47 
  

SEM, standard error of mean 

AP; African pepper, AN; African nutmeg, AP*AN; combination of AP and AN 

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Levels of inclusion (%) are indicated in parenthesis  

had the highest scores (8.9), for crumbliness and AP*AN (0.15*0.15%) had the lowest 

scores (7.8) as compared to the control product (8.2). Statistical analysis of the data 

indicated no significant (p  ˃0.05) differences between any of the treatments. Although 

mean scores indicated that AP*AN (0.1*0.05%) and AP*AN (0.1*0.15%) had the 

highest scores value (7.6) for juiciness and AP*AN (0.15*0.1%) score the lowest (5.9) as 

compared to the control (6.6), statistical analysis of the data indicated no significant (p  ˃

0.05) differences between any of the treatments compared to the control. Hence sausages 

formulated with the selected local spices at varying concentrations did not differ (p  ˃

0.05) from the control product in terms of terms of juiciness.  

 

The results for palatability and saltiness are shown in Table 2. Mean scores indicated that 

although AP treated sausage at 0.15% and AP*AN (0.1*0.1%) inclusion levels had the 

highest scores (9.1) for palatability and AN (0.1%) and AP*AN (0.05*0.1%) had the 

lowest scores (7.9) as compared to control product (8.1). Statistical analysis of the data 

however indicated no significant (p  ˃ 0.05) differences between any of the treatments 

compared to the control. Mean scores for saltiness indicated that AP*AN (0.05*0.1%) 

treated sausage had the highest scores (8.3) and AN (0.15%) scored the lowest (6.5) as 

compared to the control product (6.6). Statistical analysis of the data showed no 

significant (p  ˃0.05) differences between any of the treatments compared to the  

 

 

 

 

 

 

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Table 2. Mean Palatability and Saltiness  

  Palatability   Saltiness 

Treatment Mean SEM 

 

  Mean SEM 

 

Control 8.1 ±1.01 

  
6.6 ±0.59 

 

AN (0.05%) 8.4 ±1.01 

  
7.6 ±0.6 

 

AN (0.1%) 7.9 ±1.01 

  
7.2 ±0.59 

 

AN (0.15%) 8.1 ±1.01 

 
 

6.5 ±0.59 

 

AP (0.05%) 8.1 ±1.01 

 
 

7.1 ±0.59 

 

AP (0.1%) 8.7 ±1.01 

 
 

7.4 ±0.59 

 

AP (0.15%) 9.1 ±1.01 

 
 

6.9 ±0.59 

 

AP*AN (0.05*0.05) 8.5 ±1.01 

 
 

7.1 ±0.59 

 

AP+AN (0.05/0.1%) 7.9 ±1.01 

 
 

8.3 ±0.59 

 

AP*AN (0.05*0.15%) 8.2 ±1.01 

 
 

7.0 ±0.59 

 

AP*AN (0.1*0.05%) 8.9 ±1.01 

 
 

7.3 ±0.6 

 

AP*AN (0.1*0.1%) 9.1 ±1.01 

 
 

7.7 ±0.6 

 

AP*AN (0.1*0.15%) 8.1 ±1.01 

 
 

7.1 ±0.59 

 

AP*AN (0.15*0.05%) 8.9 ±1.01 

 
 

7.1 ±0.59 

 

AP*AN (0.15*0.1%) 9.0 ±1.01 

 
 

7.5 ±0.59 

 

AP*AN (0.15*0.15%) 8.4 ±1.01 

 

  6.8 ±0.59 

 

P-value 0.15 

   

0.21 

  

SEM, standard error of mean. 

AP; African pepper, AN; African nutmeg, AP*AN;  combination of AP and AN 

Levels of inclusion (%) are indicated in parenthesis. 

 

 

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control. Evaluation of the off flavour and overall liking of the samples at varying 

concentrations of the local spices are shown in Table 3.  

 

Table 3. Mean Off-Flavour and Overall-Liking  

  Off flavour   Overall liking 

Treatment Mean SEM 
 

  Mean SEM 
 

Control 4.2 ±1.17 

  
8.8 ±0.95 

 

AN (0.05%) 4.7 ±1.19 

  
8.9 ±0.97 

 

AN (0.1%) 3.7 ±1.18 

  
8.3 ±0.95 

 

AN (0.15%) 4.3 ±1.18 

 
 

8.5 ±0.97 

 

AP (0.05%) 4.5 ±1.19 

 
 

8.1 ±0.95 

 

AP (0.1%) 4.1 ±1.20 

 
 

8.7 ±0.95 

 

AP (0.15%) 4.6 ±1.21 

 
 

9.1 ±0.95 

 

AP*AN (0.05*0.05) 4.0 ±1.21 

 
 

8.1 ±0.95 

 

AP*AN (0.05*0.1%) 4.1 ±1.20 

 
 

8.3 ±0.95 

 

AP*AN (0.05*0.15%) 3.5 ±1.20 

 
 

8.0 ±0.95 

 

AP*AN (0.1*0.05%) 4.4 ±1.19 

 
 

8.8 ±0.95 

 

AP*AN (0.1*0.1%) 4.7 ±1.18 

 
 

8.9 ±0.95 

 

AP*AN (0.1*0.15%) 3.9 ±1.20 

 
 

8.8 ±0.95 

 

AP*AN (0.15*0.05%) 3.9 ±1.21 

 
 

9.1 ±0.95 

 

AP*AN (0.15*0.1%) 3.7 ±1.19 
 

 

9.3 ±0.95 
 

AP*AN (0.15*0.15%) 4.1 ±1.19 
 

 

9.2 ±0.96 
 

P-value 0.96 
  

 

0.62 
  

SEM, standard error of mean. 

AP; African pepper, AN; African nutmeg, AP*AN;  combination of AP and AN. 

Levels of inclusion (%) are indicated in parenthesis. 

 

 

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42 

 

Mean scores for off flavour showed that AN at 0.05% and AP*AN at 0.1*0.1% inclusion 

levels had the highest scores (4.7), while AP*AN at 0.05*0.15% had the lowest score 

(3.5) as compared to the control product (4.2).  Statistical analysis of the data showed no 

significant (p  ˃0.05) differences between any of the treatments compared to the control. 

Mean scores for overall liking indicated that although AP*AN at 0.15*0.1% inclusion 

level had the highest score (9.3), and between the two individual local spice treatments, 

sample treated with AP at 0.15 % concentration had a higher score (9.1) and AN at 

0.05% concentration had (8.9) among its inclusion levels. AP treated sample at 0.05% 

and AP*AN at 0.05*0.05% inclusion levels scores the lowest (8.1) as compared to the 

control products (8.8), and statistical analysis of the data indicated no significant (p  ˃

0.05) differences between any of the treatments. 

 

4.2. Microbial Analysis  

Aerobic bacteria, coliforms and E. coli were counted for the respective treatments stored 

for 0, 3, and 6 days at 4
o
C. (Table 4). Compared to the control, substituting AN with 

nutmeg up to 0.15% significantly increased aerobic bacteria count. However, the 

substitution did not affect coliform and E. coli counts.    

 

 

 

 

 

 

 

 

University of Ghana http://ugspace.ug.edu.gh



43 

 

Table 4. (Log10 CFU/g) Count of Aerobic Bacteria, Coliforms and E. coli  

Treatment APC SEM Coliform SEM E coli SEM 

 

Control 6.93
a
 ±0.33 6.55 ±0.17 3.01 ±0.53 

 

AN (0.05%) 7.19
c
 ±0.33 6.67 ±0.17 2.55 ±0.53 

 

AN (0.1%) 7.22
c
 ±0.33 6.70 ±0.17 3.51 ±0.53 

 

AN (0.15%) 7.09
b
 ±0.33 6.67 ±0.17 2.50 ±0.53 

 

AP (0.05%) 6.94
a
 ±0.33 6.45 ±0.17 1.67 ±0.53 

 

AP (0.1%) 7.01
a
 ±0.33 6.53 ±0.17 2.53 ±0.53 

 

AP (0.15%) 6.95
a
 ±0.33 6.30 ±0.17 0.85 ±0.53 

 

AP*AN (0.05*0.05) 7.12
b
 ±0.33 6.64 ±0.17 2.64 ±0.53 

 

AP*AN (0.05*0.1%) 6.94
a
 ±0.33 6.47 ±0.17 2.18 ±0.53 

 

AP*AN (0.05*/0.15%) 6.93
a
 ±0.33 6.35 ±0.17 1.26 ±0.53 

 

AP*AN (0.1*0.05%) 7.06
a
 ±0.33 6.45 ±0.17 1.82 ±0.53 

 

AP*AN (0.1*0.1%) 7.04
a
 ±0.33 5.80 ±0.17 1.64 ±0.53 

 

AP*AN (0.1*0.15%) 7.02
a
 ±0.33 6.51 ±0.17 2.5 ±0.53 

 

AP*AN (0.15*0.05%) 7.01
a
 ±0.33 6.55 ±0.17 2.08 ±0.53 

 

AP*AN (0.15*0.1%) 6.98
a
 ±0.33 6.65 ±0.17 2.05 ±0.53 

 

AP*AN (0.15*0.15%) 6.97
a
 ±0.33 6.68 ±0.17 2.53 ±0.53 

 

P-value 0.62 

 

     0.62 

 

  0.62 

  

AP; African pepper, AN; African nutmeg, AP*AN; combination of AP and AN 

APC; Aerobic plate count, SEM: Standard error of mean 

Means with the same superscripts within a column are no