Hazards Associated with Holding and Reheating Foods at Vending Sites in a Small Town in Zambia

Hazard analyses were done at 11 cooked-food-vending sites and related food-vending operations in a small-town market along a highway in Zambia. The analyses consisted of observations and time-temperature measurements at the vending sites and interpretations of results of laboratory tests of samples of foods (including leftovers) collected after holding and reheating. Salmonellae were isolated from dried ants, a cooked meatball on display, and pumped river water used by the vendors. Ants for sale at the market contained 10⁷ Bacillus cereus cells per g. Nshima (boiled maize meal) was held at high temperatures in pans over glowing charcoal in which steam was generated throughout the entire holding period during the day, preventing bacterial growth. Large populations of B. cereus , however, were isolated from a sample left overnight at ambient room temperature. Cooked foods other than nshima were held at room or outdoor ambient temperatures throughout the day and overnight. High aerobic mesophilic colony, thermotolerant coliform and, in a few foods, Escherichia coli counts were found in foods after several hours of holding during the day of preparation and of foods held overnight. Temperatures attained during reheating were variable and sometimes would have resulted in survival of foodborne pathogens that multiplied during holding.