Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2015
Publication Date: 3/11/2015
Publication URL: http://handle.nal.usda.gov/10113/60938
Citation: Rasooly, R., Hernlem, B.J., He, X., Friedman, M. 2015. Plant compounds enhance assay sensitivity for detection of active bacillus cereus toxin. Toxins. 7(3):835-845. doi: 10.3390/toxins7030835.
Interpretive Summary: Bacillus cereus is an important cause of food poisoning resulting in vomiting and diarrhea by a toxin it produces. About 84,000 cases occur in the U.S. each year at a cost of some $36 million. Food safety relies on being able to trace and identify low levels of the active toxin. We were able to detect small amounts of the toxin in things such as soy milk, rice milk and baby formula that have been connected with food poisonings. Interestingly, our test was more sensitive when certain plant extracts were added during the tests. This method can help improve food safety and reduce the costs to society of food poisonings.
Technical Abstract: Bacillus cereus is an important food pathogen, producing emetic and diarrheal syndromes, the latter mediated by enterotoxins. It has been estimated that there are 84,000 cases of B. cereus food poisoning in the US each year, with an annual cost of USD 36 million. The ability to sensitively trace and identify this active toxin is important for food safety. This study evaluated a nonradioactive, sensitive, in vitro cell based assay based on B. cereus toxin inhibition of GFP protein synthesis in transduced Vero cells combined with plant extracts or plant compounds that reduce viable count of B. cereus in food. The assay exhibits a dose dependent GFP inhibition response with ~25% inhibition at 50 ng/mL toxin evaluated in culture media or soy milk, rice milk or infant formula, products associated with food poisonings outbreak. The plant extracts of green tea or bitter almond and the plant compounds epicatechin or carvacrol were found to amplify the assay response to ~90% inhibition at the 50 ng/mL toxin concentration greatly increasing the sensitivity of this assay.