Growth of Bacillus cereus isolated from some traditional condiments under different regimens

Abstract

Bacillus cereus is ubiquitous in nature and constitutes a major portion of the microbial flora of food contaminating various food samples, causing food spoilage and poisoning to the detriment of the consumers. This work was designed to study the growth characteristics of B. cereus strains isolates from traditional condiments under different growth conditions. 34 Bacillus strains were isolated from 4 local condiments iru (fermented Parkia bioglobosa seeds), ogiri (fermented Citrullus vulgaris seeds), dawadawa (fermed soy bean-Glycine max seeds) and okpehe (fermented Prosopis africana seeds) and identified as B. cereus, B. subtilis, B. pumilus and B. lichenifomis. B. cereus had the highest occurrence of 38.24%. All the B. cereus strains had their optimum and minimum growth at 37 and 4°C, respectively, while none grew at 100°C and at pH 1 and 12 when incubated for 48 h. All the B. cereus isolates had their highest growth at 10% concentration of monosodium glutamate and the lowest at 40% but their growth pattern in NaCl is strain dependent with optimum growth between 7 and 9% NaCl concentration, and as the time of exposure to ultraviolet light increased the growth decreased.