Multiplex Polymerase Chain Reaction for Detection of Toxin Genes of Bacillus cereus Group Isolated from Meat and Chicken Products

Bacillus cereus sensu lato (B. cereus s. l.) is a significant cause of food spoilage issue owing to the activity of certain hydrolytic enzymes. This study aimed to detect the incidence and contamination level of meat and chicken products with B. cereus group in Sharkia Governorate, Egypt, with reference to their enterotoxin genes` profiles. Overall, 43 out of 200 (21.5%) examined samples were contaminated by B. cereus group, with identification of only one species, B. cereus. B. cereus group isolates were frequent in chicken samples (25.71%), with the highest incidence in chicken meat (30%) followed by chicken sausage and chicken luncheon (25% each). Meanwhile, they were isolated from 19.23% of examined meat products, which predominated in meat burger (25%), followed by each of meat kofta, shawarma, and luncheon (20% each), minced meat (17.14%) and meat sausage (15%). Of interest, the highest B. cereus count (>10 colony forming units (CFU)/ g) was found in 2% of positive samples, with a higher percent in meat sausage (33.33%). Whereas 15.5% of positive samples harbored B. cereus with counts ranging from >1x10-10 CFU/g. Molecular analysis of B. cereus enterotoxin genes using multiplex polymerase chain reaction (PCR) revealed that both ces and nhe genes were detected in 100% of the examined isolates, while cytk and hbl genes were present only in 9.52% and 23.8% of analyzed isolates, respectively. These findings, involving a higher occurrence of B. cereus and their toxin genes in meat and chicken products represent a serious public health concern in Egypt.