Microbial safety of raw mixed-vegetable salad sold as an accompaniment to street vended cooked rice in Accra, Ghana

Abstract

A survey of 90 randomly selected subjects indicated raw mixed-vegetable salad as a popular accompaniment to cooked rice sold by street-food vendors in the Kokomlemle municipality of Accra, Ghana, but the salad was generally considered unwholesome and a potential cause of diarrhoea. A survey of 15 vendors of cooked rice indicated that the sources of raw vegetables, method of transportation from the sources to the kitchens, and methods of storing the raw vegetables before processing, as well as the methods of processing and sale, made the raw mixed-vegetable salad accompaniment a potential source of food poisoning from microbial contamination. Microbial analysis of samples of the salads obtained from five randomly selected vendors in the mornings and afternoons, over 15 days, indicated that bacterial counts for all samples exceeded the recommended World Health Organization (WHO) standard of Log10 3.0 cfu/g. Levels of Pseudomonas, Salmonella typhi, Shigella sp., and Streptococcus faecalis did not show any significant difference (P<0.05) among vendors and did not differ significantly (P<0.05) over the 15 days. Significantly, higher levels of microbial contamination (P<0.05) occurred in the afternoon, than in the morning samples. The results confirm that the raw mixed vegetable salads which are sold as accompaniment to street vended cooked rice in the Kokomlemle municipality contain S. faecalis from fecal contamination, Pseudomonas, Shigella sp., and S. typhi which could cause gastrointestinal infections and the highest risk was from the afternoon samples.

Key words: Ghana, street vended cooked rice, raw mixed-vegetable salad, microbial contamination.