INCIDENCE OF BACILLUS CEREUS STRAINS IN FOOD CONSUMED BY SCHOOL CHILDREN IN ILORIN METROPOLIS

Abstract

Foodborne diseases are caused by eating contaminated food. Bacillus cereus is a versatile enterotoxigenic agent of foodborne disease. This study investigated the incidence of Bacillus cereus in food sold within some school premises within Ilorin metropolis and their hazard analysis critical control point (HACCP). Isolation of Bacillus cereus was carried out using food samples collected from some selected school within Ilorin metropolis using Bacara agar. The isolated bacteria were characterized and identified following microbiological techniques. Molecular identification of isolates was done using 16S rRNA sequencing method. Effect of physiochemical parameters (such as incubation period, temperature, pH, UV-light, salt concentration and monosodium glutamate concentration used in cooking) on the growth of the isolates was carried out. Identification of possible points of contamination was assessed from the points of production and sale of foods using well structured questionnaire. Total Bacillus count in food samples sold in all the sampled points within the Local Government Areas was significantly different from each other. Cooked Rice and spaghetti were found to have the highest count (4.42 ± 0.72 to 4.75 ± 0.89 and 4.00 ± 0.99 to 4.17 ± 1.03). All the isolates were confirmed to be Bacillus cereus with accession number OQ235070, OQ235071, OQ235072, OQ235073, OQ235075 and OQ235076 except one confirmed to be B. thuringiensis OQ235074. The isolates were found to have optimum growth between 30 – 35 0C, pH 3 - 7, incubation period of 12 - 24 hours and hours and maximum growth at 1.0 % monosodium glutamate concentration. Hazard analysis critical control point reveals poor storage system, illiteracy and poor hygienic practices among the handlers. In conclusion, food items sold to school children examined were found to be contaminated with Bacillus cereus.