Toxin profiles of Bacillus cereus occurring in high numbers in spontaneously fermented African locust beans (Parkia biglobosa)

Research output: Contribution to conferenceConference abstract for conferenceResearch

Line Thorsen, Paulin Azokpota, Bjarne Munk Hansen, Mogens Jakobsen

Bacillus cereus was reported to occur in high numbers (up to 107 CFU/g) during spontaneous fermentation of three different traditional Benin condiments; afitin, iru and sonru made from African locust beans. A total of nineteen B. cereus isolates from the ferments, were examined for the presence of toxin genes related to food poisoning using PCR. Isolates harboring the emetic specific gene fragment EM1 where highly representative, being one out of ten isolates from afitin, one of one isolate from iru and five of eight isolates from sonru. Three of the isolates from afitin harbored the cytotoxin K gene. The non hemolytic enterotoxin complex genes were present in all isolates, while the hemolytic enterotoxin complex genes were present in only one isolate from afitin. Food poisoning potential was evaluated using a Vero-cell assay measuring cytotoxity, and the toxin titers ranged between 80 and 1280. Isolates from afitin were the most cytotoxic. The emetic isolates from afitin, iru and sonru were low to high producers of cereulide, producing between 130-800 µg cereulide/g biomass (wet weight) at 30oC, as quantified using liquid chromatography mass spectrometry. Cereulide formation during fermentation of locust beans has not been demonstrated. Interestingly afitin, iru and sonru are considered safe food products, and as far as is known there has been no reports on diarrhea or vomiting due to the consumption of the three condiments.
Original languageEnglish
Publication date2007
Number of pages1
Publication statusPublished - 2007
EventBacillus - ACT 2007: International Conference on Bacillus anthracis, B. Cereus, and B. thurigingiensis - Oslo, Norway
Duration: 17 Jun 200721 Jun 2007

Conference

ConferenceBacillus - ACT 2007: International Conference on Bacillus anthracis, B. Cereus, and B. thurigingiensis
CountryNorway
CityOslo
Period17/06/200721/06/2007

ID: 8109017