Quality and Safety of Ready-To-Eat Street-Vended Foods Sold in Selected Locations within Thika Town, Kiambu County, Kenya

Abstract

The safety of street foods remains a public health concern, especially in developing countries like Kenya where foodborne illnesses associated with these foods have often been reported. Their consumption has the potential to cause foodborne diseases due to contamination with pathogenic microorganisms as well as the presence of toxic chemical contaminants. The objective of this study was to determine the level of food safety knowledge and practice of street food vendors and to determine the microbial and chemical quality of ready-to-eat street-vended foods sold in selected locations within Thika Town of Kiambu County in Kenya. The study targeted 385 street food vendors in six locations including Thika town center, Ngoigwa, Juakali area, Makongeni, Kiandutu slums, and the area surrounding Thika Level 5 hospital. Data collection was accomplished through face-to-face interviews using structured questionnaires and observation using an assessment tool for observation of personal hygiene and food handling practices of SFVs and the condition of the vending environment. A total of 199 food samples consisting of cereals, sliced fruits, salads, groundnuts, tubers, fruit juices, boiled deshelled eggs, smokies, and sausages were randomly collected for microbial and chemical analysis. Determination of total viable counts, total coliform counts, yeast and molds counts, Escherichia coli counts, Staphylococcus aureus counts as well as the presence of Salmonella spp., and Listeria monocytogenes were determined following standard microbiological methods. The concentrations of lead and cadmium were determined by atomic absorption spectrophotometry while acrylamide in french fries was determined using high-performance liquid chromatography. Total aflatoxins and aflatoxin B1 in cereal-based foods and groundnuts were determined using a competitive direct enzyme-linked immunosorbent assay. The results indicated that the majority of the street food vendors were male (63.2%) with 38.1% of them having attained secondary school education. About 93% of the SFVs had not received any formal training on food hygiene and safety. The majority of street food vendors handled food with bare hands (96.8%) or handled money while serving food without washing hands (86.1%). Few vendors appropriately preserved their food with 78.3% storing foodstuff that required refrigeration at ambient temperatures. Whereas public health officers’ visits were found to significantly (p<0.0001) motivate street food vendors to obtain a food handler's medical certificate, only about 27% had obtained it. Good food safety and hygiene awareness scores were significantly (p<0.05) influenced by education level, food hygiene, and safety training, mobility of street food vendors, public health inspection, and the category of street food vendors. The levels of total viable counts, total coliform counts, yeast and mold counts, Escherichia coli, and Staphylococcus aureus ranged from 6.59 to 3.38, 5.57 to 1.59, 5.05 to 1.60, 2.03 to 0.00, and 5.97 to 1.89 Log10 CFU/g respectively. At least nine food samples were contaminated with Escherichia coli although the chance for contamination was significantly (p = 0.0002) higher (15 times) in plant-based foods compared to animal-based foods. At least one sample in each food type was contaminated with Staphylococcus aureus with contamination levels above 1.89±1.66 Log10 CFU/g. Listeria monocytogenes was not detected in any food sample. The level of lead contamination in street-vended foods ranged between 0.271±0.070 and 1.891±0.130 mg/Kg with groundnuts recording significantly higher (p<0.0001) mean levels (1.891 mg/Kg) than other food types. These concentrations exceeded the maximum allowable limits set by the Joint Food and Agriculture/ World Health Organization food standards program. The mean acrylamide level for the street-vended french fries in Thika town was 0.558±0.128 μg/g, higher than the European Union benchmark value of 0.5 μg/g. Total aflatoxin and aflatoxin B1 in street-vended groundnuts averaged between 4.4 - 14.2 µg/kg and 3.4-11.3 µg/kg, respectively. On average 16.7% and 44.4% of groundnut samples exceeded the total aflatoxin and aflatoxin B1 limits established by the Kenya Bureau of Standards, respectively. In addition, 72.2% and 100% of the groundnut samples exceeded the limits for total aflatoxin and aflatoxin B1 set by the European Union, respectively. These findings suggest that street-vended foods sold in this study area are of public health concern as they potentially can cause illnesses to consumers. Consequently, there is a need to regulate the informal food processing and marketing channels to enhance their quality and safety standards. The public health sector should enhance awareness among street food vendors and consumers on food hygiene and safety through training. In addition, the provision of basic infrastructure for enhancing hygiene among street food vendors, continuous monitoring of street-vended foods by the public health department to identify potential contaminants and the establishment and enforcement of policies to govern the street-vended food businesses may contribute to improved quality and safety of these foods.