Salmonella, Shigella and growth potential of other food-borne pathogens in Ethiopian street vended foods

Abstract

Objective: To evaluate the bacteriological safety of food items sold by street vendors with regard to Salmonella and Shigella and to assess the growth potential of some foodborne pathogens in some street foods. Design: Collection of street-vended foods and laboratory based microbiological analysis. Setting: Microbiology Laboratory, Department of Biology, Addis Ababa University, Addis Ababa, Ethiopia. Results: Most of the street food samples had aerobic mesophilic counts >107 cfu/g. Nine "kitfo" and one "egg sandwich" samples yielded Salmonella. Shigella was isolated from three "macaroni" samples. The Salmonella isolates were sensitive to all ten drugs tested but the Shigella isolates had multiple resistance against five drugs. In a challenge study, Salmonella typhimurium, Shigella flexneri and Staphylococcus aureus grew in street-vended food samples to hazardous levels within eight to twelve hours. Conclusion: Street foods are heavily contaminated with micro-organisms and are potential sources of food borne infections. Health hazards from street foods may be significantly minimised by consumption within four hours of preparation.