Determination of enterotoxin genes in Bacillus cereus from raw milk using multiplex polymerase chain reaction technique

Abstract

A Gram-positive bacterium, which can usually be found in cultivating plants and soil, causing it commonly universal is regarded as Bacillus cereus. It is said that most strains present in B. cereus is specifically called the primary cause of food poisoning illnesses which is characterised by either emetic or diarrheal syndrome, the most essential purpose of the current research was, therefore, to isolate and identify the enterotoxin genes in B. cereus through using a multiplex polymerase chain reaction (mPCR)technique. To achieve this aim, thus B.cereus was isolated from raw milk then cultured on mannitol egg yolk polymyxin agar and chromogenic B. cereus agar. The samples were then examined using biochemical investigation then established using partial sequencing of 16SrDNA. Among 40 samples, 20 of them were found to contain hblC and hblD, a hemolytic enterotoxin (HBL) complex encoding genes. The total mean of contamination samples in the B. cereus was proved to be higher (1.4×10⁵ – 3.2×10⁵ CFU/mL) than the acceptable detection level of B. cereus in dairy products ~10³ CFU/mL. The isolates (10%) were shown to express hblC gene whereas the isolates (20%) were shown to express the hblD gene. The findings suggested that the detected enterotoxin genes of B. cereus which were found in raw milk may create a potential danger to the health of the public.