Optimize risk assessment for ready-to-eat chilled products.

Sales and consumption of ready-to-eat cooked chilled foods are increasing rapidly. At the Institute of Food Research (IFR), scientists have developed and tested novel techniques, approaches and interfaces that will enable you to improve your quantitative microbial risk assessment (QMRA) of products. Such quantitative assessments must encapsulate all available information and data relevant to a particular foodborne hazard and simultaneously allow for an unbiased inspection by a wide range of observers.

Several computer-based information-handling schemes meet these objectives. A strategy based on Bayesian Belief Networks (BBNs) has proved most useful. BBNs are similar to flow diagrams and provide a powerful means by which mathematical modelers and safety experts can collaborate on problems. A BBN is a numerical framework in which scientists can save pieces of information and data, document them and combine them in an unbiased way.

In collaboration with European partners, IFR researchers have successfully completed a QMRA for ready-to-eat cooked chilled foods. Using hazard identification and characterization techniques, investigators showed C. botulinum and B. cereus to be major hazards. Exposure assessment was concerned with research in areas of food microbiology that are relevant to the QMRA: the enumeration and characterization of the most hazardous spore-forming pathogens. Investigators carried out risk characterization using BBNs with existing literature data and new data generated in this effort. The result--QMRAs of pathogenic spore-forming bacteria in commercial cooked chilled foods--is already attracting considerable interest from the food industry.

BBNs that represent foodborne hazard domains incorporate manufacturing information, expert opinions, predictive microbiology and consumer behaviors within a single model. The assessment tools constructed at IFR not only offer a way to estimate the size of crucial end-point measures, such as the level of exposure and risk, but also identify the importance of uncertainties and sensitivities that are part of the food safety equation.

FYI: U.S. data suggest that about 70% of all foodborne diseases are caused by viruses. Although reported U.K. figures are much lower, it appears that U.K. researchers seriously underestimate the incidence of foodborne viral infections. The major causes of viral gastroenteritis are the small round-structured viruses. These are single-stranded RNA viruses belonging to the family Caliciviridae.

In new work at IFR, scientists are attempting to express purified viral capsid protein in a heterologous system so that they can study how attachment occurs to cultured cells. They also want to investigate strain evolution and predict the emergence of new strains using genome comparisons and bioinformatics. Further information. Mike Peck, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, England, U.K.; phone: [phone]; fax: [phone]; URL: www.ifr.bbsrc.ac.uk.