Isolation And Safety Analysis Of Bacillus Thuringiensis In Food From Supermarket

Bacillus thuringiensis(Bt) have been widely used as one of the most effective microbial pesticides all around the world. However, some reports, during these years, illustrated the occurrence of food poisoning, as a result the safety of Bt had become the focus of attention. In this study, the samples of bread, jelly, milk, and green-tea products were collected from supermarket in Fujian Province, China. A total of forty-two Bt strains were isolated from 305 ready-to-eat food samples, six from milk, one from milk slice, eight from bread, one from green-tea beverages, three from instant noodles and twenty-three from jelly.Bt isolates were characterized by PCR analysis,with the primers described previously used to detect Bc enterotoxigenic genes: hemolysin BL (Hbl), non-hemolytic enterotoxin (NHE) and one-component toxins CytK, BceT and EntMF. And the PCR analysis revealed that most of Bt isolates produced these five enterotoxigenic genes, suggesting the Bc enterotoxigenic genes were widely disturbed in food and beverages.Bt isolates were characterized by SDS-PAGE and PCR analysis for cry1A gene. The result of PCR analysis revealed that most of the Bt isolates were detected harboring cry1A, except BRC-SFR40, BRC-SFR42 and BRC-SFR50. And SDS-PAGE demonstrated that Bt isolates from ready-to-eat food produced main bands of 130 kDa, 65 kDa, 25 kDa and 20 KDa, while BRC-SFR41 also produced a band of 75 kDa and BRC-SFR28 also produced bands of 27 kDa, 50 kDa and 75 kDa.