Today’s problem in managing quality of pre-packed foods and ready-to-eat foods includes, that in most cases the food borne diseases ofB.cereus occur at a much higher frequency than indicated by reports.

Indeed, no causative agent is found in about 50% of investigated foodborne disease outbreaks, in the USA. A number of these may well have been caused by B.cereus and related toxins e.g. in fried rice foods, but will only be confirmed when a routine analytical test exists.

We evaluated a proteomics-based approach to monitor secreted protein toxins. Our approach was compared to the routine and official methods, based on ISO 7932 norms, which detect only presumptive B.cereus, without indicating the potential of toxin synthesis, which has no sufficient importance for the evaluation of the food. Furthermore, in this study foodborne isolates of B.cereus were genome sequenced and the presence or absence of toxin-synthetizing genes was determined, serving as basis for the evaluation of the toxin tests. Results of the study will serve as a basis to future applications of the toxin tests in proteomics type arrays of multiple food intoxications.

The current project was run in good complementarity between different institutes of HES-SO. The Geneva-based hepia institute analysed the B.cereus toxin genes by sequencing the genomes of foodborne B.cereus strains. The Sion-based Life Technologies institute established the test of the produced toxins. Collaborations with the University of Munich (D), the University of Bern, Agroscope and BAG institutes (Bern), and the Spiez Toxicology laboratories also resulted from this project. Furthermore, promising interactions with the in vitro Diagnostics platform from Swiss Biotechnet including industrial partners were launched during this project. The study was already, and continuous to be, published in scientific articles [Crovadoreetal.2016] [Tonacini et al.2016 in prep.].


Bruno Schnyder

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