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New Detection of Emetic Bacillus cereus Strains in Just One Day

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Oct 2019. Some Bacillus cereus strains produce toxins that can lead to a food-borne disease. Eurofins offers immunological detection and - new - detection of the gene for the emetic toxin in just one day. GLISA and PCR provide rapid and specific results for the detection of toxin formation capacity and toxin gene supply of presumed Bacillus cereus.

Current Status of Detection

For the assessment of the toxinogenic relevance of a detection of presumptive Bacillus cereus, the germ count on the one hand and the toxin formation capacity on the other hand are decisive (ALTS Ad-hoc-AG Art. 14, Empfehlung zu bedenklichen Mikroorganismen (recommendation on microorganisms of concern), 2010). The Duopath® test (VWR) enables the detection of HBL and NHE diarrhoea enterotoxins in culture supernatants of Bacillus cereus isolates or in culture enriched food. The detection of toxins, e.g. in food, can only be performed in complex cell culture assays. The same applies to the emetic toxin, which causes violent vomiting.

Problem of the Current Evidence

An immunological test system for this heat-stable toxin has been withdrawn from the market. The cell culture detection of the emetic toxin in food directly or in culture supernatants is no alternative for urgent routine decisions. In addition, emetic strains of presumed Bacillus cereus may be present in the food at delivery, but not the toxin, because it is only formed after spores have germinated during storage or when cooked starchy foods (rice, pasta, gnocchi, etc.) are kept warm in an irregular manner, or because the toxin is released by absorption of the living germs in the intestine. It is therefore of great interest to be able to detect these B.cereus strains directly in food.

The Solution to the Problem

Eurofins Inlab is now able to detect Bacillus cereus strains that form the diarrhoea toxins as well as those that carry the gene for the production of emetic toxin by PCR after a short culture period. The validation study included products containing starch (e.g. gnocchi) as well as dairy products (ricotta). Of course, isolated strains can also be tested. The validation has been completed. The transfer to routine is about to be completed.

Do You Have Any Questions?

Questions regarding the tested food and the test duration should be directed to our expert Dr Jens Kroll.