The microbiological quality of informally vended foods in Harare, Zimbabwe

The aim of the present study was to evaluate the microbial quality of the informally (street) vended foods in Harare. Samples of the staple food sadza (thickened maize porridge), stews (beef, chicken, goat), fried vegetables, salads, tap water and wash water, hand and surface swabs, were tested for the presence of selected pathogenic microorganisms. The food samples were tested for the presence of Bacillus cereus and Salmonella sp., while the water samples were tested for Escherichia coli. Hand and surface swabs were also taken and tested for the presence of Staphylococcus aureus and E. coli. The fried vegetables had the highest incidence of samples that tested positive for B. cereus (31%; n = 222) followed by salads (21%; n = 70). The salad (14%) and vegetable (7%) samples had the highest incidence of contamination with Salmonella sp., while sadza and the stews had fewer contaminated samples. The salads and fried vegetables therefore posed the greatest risk of food poisoning among the foods sold by the vendors. About 32% of hand swabs (n = 251) were positive for S. aureus with only 6.4% positive for E. coli. Some swabs from spoons, knives, cutting boards and plates were also positive for E. coli and S. aureus, but with lower incidences compared to hand swabs. These results suggest that some of the vendors’ hands were unacceptably contaminated, indicating poor hygienic practices. Only three wash water samples (n = 240) tested positive for E. coli, while none from the municipal water points (n = 45) were positive. A comparison of surface and hand swabs between vending sites showed that the highly crowded markets had difficulties in meeting good hygienic standards. The training of vendors in food hygiene and provision of appropriate infrastructure were identified as key issues to the improvement of the safety of informally vended foods in Harare.