New methods for the detection of enterotoxins (diarrhoeal toxins) from Bacillus cereus have been developed by European scientists. The discovery paves the way for the identification of genes responsible for the production of emetic toxins (vomiting toxins).
B. Cereus is a spore-forming food-borne pathogen which causes gastroenteritis, diarrhoeal syndrome or emetic syndrome, via several enterotoxins and an emetic toxin. The virulence is highly dependent on the specific strains, and to-date no methods exist to differentiate between these.
Led by Christophe Nguyen at INRA in Avignon, France, the main objectives of the European-funded study are to identify highly virulent food poisoning strains of B. Cereus and to propose methods and tools to reduce their incidence in foods.
Scientists will investigate the diversity of virulence among B. Cereus strains and the ecology of the virulent ones in order to identify the contamination routes. In addition, the researchers will estimate the risk for their presence and development in foods and improve the dose response curve.
To kick off with, in the first six months of the study scientists developed new and highly sensitive immunological methods to detect the diarrhoeal toxins. They have also identified the genes responsible for the production of emetic toxins, allowing the development of a PCR method - Polymerase Chain Reaction methods are analytical and enzyme based methods used to detect very small quantities of DNA in a crop or sample - to detect the emetic strains.
Although the bacteria may be found in most foods, products containing vegetables and milk, which may be contaminated from the soil, pose a particularly high risk.
Further information can be obtained from the project co-ordinator, Christophe Nguyen.