Occurrence and Risk Assessment of Foodborne Hazards Along the Tomato Production and Retail Value Chain

Abstract

Unprocessed tomatoes and tomato-based red pepper sauce are significant contributors to food and nutrition security in Ghana. Tomatoes are primarily consumed cooked, but a substantial number of people also eat them raw in salads and as garnishes. Unsanitary and unhygienic practices along the unprocessed tomatoes value chain and in the processing of tomato-based red pepper sauce have led to documented occurrences of microbial contamination and pesticide residues, which are food-borne hazards. This study aimed to assess the risk of microbial and pesticide residues contamination in unprocessed tomatoes and tomato-based red pepper sauce. A cross-sectional design was used to evaluate consumption patterns through a survey of 420 respondents from selected regions. A total of 320 samples (180 unprocessed tomatoes, 140 tomato-based red pepper sauce) were collected from major markets, vendors, and farms. Microbial (Salmonella and Klebsiella pneumoniae) and organophosphate pesticide residue analyses were conducted on 160 samples each using standardized methods. The risk assessment followed the Codex protocol. Consumption patterns were daily and weekly with higher consumption quantities (25g -100g) for unprocessed tomatoes and tomato-based red pepper sauces. Females are 2.80 times more likely to consume tomatoes for their taste, while public servants and self-employed individuals are 19 times and 3.72 times, respectively, more inclined to consume tomatoes for nutritional reasons. Klebsiella pneumoniae was detected in 24 out of 90 unprocessed tomato samples, resulting in a prevalence rate of 26.6%. Additionally, it was found in 23 out of 70 tomato-based red pepper sauce samples, corresponding to a prevalence rate of 32.8%. The mean concentration of Klebsiella pneumoniae in unprocessed tomatoes and tomato-based red pepper sauce was 2.82 ± 0.37 Log CFU/g and 2.87 Log CFU/g respectively. The concentration of Salmonella in unprocessed tomatoes was measured at 3 Log CFU/g. The estimated exposure to Klebsiella pneumoniae from tomato-based red pepper sauce and unprocessed tomatoes led to approximately 10 and 8 cases of illness per 100,000 individuals, respectively. In contrast, the risk of Salmonella infection from the consumption of unprocessed tomatoes is significantly higher, with an estimated 707 cases per 100,000 individuals. These figures highlight a serious risk, especially for those consuming unprocessed tomatoes from informal markets that lack proper washing protocols. Chlorpyrifos was detected in 5 out of 18 unprocessed tomatoes samples, resulting in a prevalence rate of 27.7 %, and 4 out of 14 tomato-based red pepper sauce samples, corresponding to a prevalence rate of 28.5% . The mean concentration of chlorpyrifos detected in unprocessed tomatoes and tomato-based red pepper sauces were 0.34 ±0.19 mg/kg and 0.0168 ±0.0101mg/kg. The mean concentration of chlorpyrifos detected in unprocessed tomatoes was 0.34 ± 0.19 mg/kg, while in tomato-based red pepper sauces, it was 0.0168 ± 0.0101 mg/kg. Furthermore, consumers are exposed to elevated levels of chlorpyrifos through their intake of unprocessed tomatoes, estimated at (3.3x10-2 ± 0.23 mg/kg bw/day and tomato-based red pepper sauces, estimated at 1.8´10-2± 0.01 mg/kg bw/day. This exposure raises serious health concerns, as the calculated margins of exposure (MoEs) violated the limits set by the European Food Safety Authority (EFSA). This indicates potential risks related to cancer, reproductive issues, and neurotoxic effects among individuals in the study area. Consumers are at higher risk of salmonellosis from unprocessed tomatoes compared to the risk of Klebsiella pneumoniae infection from unprocessed tomatoes and tomato-based red pepper sauce. Consumption of chlorpyrifos-contaminated unprocessed tomatoes and tomato-based red pepper sauce also poses a significant cancer and neurotoxic health risk. Improvements in hygienic practices, agricultural production, post-harvest handling of unprocessed tomatoes, and the processing of tomato-based red pepper sauce are recommended to mitigate these risks.