Microbiological survey of street-vended salad and gravy in Johannesburg city, South Africa

Salad (55) and gravy (55) samples were collected over a period of 4 months from 16 street vendors located in central Johannesburg and working under conditions perceived as unsuitable for the preparation and selling of ready-to-eat foods. Standard methods were used to determine aerobic plate counts (APC), gram-negative counts (GC) and spore counts (SC). Predominant colonies (362) were isolated from APC plates of the highest dilution showing growth of all samples and characterised to genus level. The incidence of Bacillus cereus and Clostridium perfringens in 35 salad and 35 gravy samples was also determined. Mean APC and SC values of salad samples were significantly higher (P<0.05) than those of gravy samples. No significant differences (P>0.05) were, however, observed between mean GC values of salad and gravy samples. The 362 predominant isolates recovered from APC plates of salad (190) and gravy (172) samples were mostly Bacillus spp. and Micrococcaceae. B. cereus was not detected in any of the samples analysed and C. perfringens was detected in 1 gravy and 1 salad sample. It was concluded that the quality and safety of salads and gravies analysed in this study was acceptable despite the observed unhygienic food handling practices and unsanitary environmental conditions under which the vendors operated.