Microbial Contamination of Food Milling Machines in Two Major Markets in Accra

Abstract

Background: Food safety remains a critical public health concern, particularly in urban markets where unsanitary practices prevail. Some undesired implications of food contamination include foodborne illnesses, economic losses, and damage to public trust in the food supply chain. Although food milling machines are becoming increasingly common in Ghana, very little is known about their role in food safety. Aim: This study aimed to assess the microbial contamination of food milling machines and its effect on milled food in Accra. Methods: This was a descriptive cross-sectional study carried out at two major markets in Accra, Agbogbloshie and Makola. A total of 134 food milling machines were sampled in this study. Three swabs from various components of every milling machine were obtained using sterile swab sticks pre-moistened in peptone water. Additionally, food samples, before and after milling, were collected into sterile containers. All the samples were analyzed using standard microbiological methods, including antimicrobial susceptibility testing. A structured questionnaire was administered to machine operators to gather information on hygiene practices, cleaning routines, knowledge of food safety, and conditions around the milling machines. Results: A total of 98 bacterial species were identified in the swab samples from the machines, with 13 species being of public health importance. The predominant organisms isolated were Klebsiella pneumoniae (39%), Pseudomonas aeruginosa (12.5%), Enterobacter hormaechei (10%), and Enterococcus faecium (8%). The mean total plate count (TPC), coliform plate count (CPC), and fecal coliform count (FCC) before milling were 528.3 x 102, 208.2 x 102, and 43.1 x 102, respectively, while TPC, CPC, and FCC after milling were 1088.8 x 102, 814.6 x 102, and369.2 x 102, respectively. Comparing unmilled and milled food samples, it was observed that milling machines were a source of microbial contamination in all the milled food samples. Some bacterial isolates from the milling machines exhibited a high prevalence of multidrug resistance (MDR). These included E. cloacae (61.5%), E. hormaechei (28.6%), E. coli (20.8%), and K. pneumoniae (4.4%). The hygienic and safety practices of the milling machines were poor, with all the machines not being, thoroughly cleaned after use. Conclusion: The study identified a wide spectrum of bacteria that contaminated milling machines at the two markets in Accra, some of which had a high prevalence of MDR. Hence, there is a need for infection control practices at the milling sites to protect public health.