Food-borne Listeria monocytogenes risk assessment

Listeria monocytogenes is ubiquitous in the environment and in food process ing plants. Consequently, foods are frequently contaminated. However, the o ccurrence rate of listeriosis is only about five cases per million people p er year. Listeriosis primarily strikes immunocompromised individuals, pregn ant women and the elderly with a fatality rate of 20-25%. The FDA is in the process of finishing a risk assessment that is being conducted as an initi al step in reviewing its approach to maximizing the public protection from foodborne L. monocytogenes. The risk assessment evaluated the presence and quantitative levels of L. monocytogenes in 21 groups of ready-to-eat foods. The potential growth of L. monocytogenes between retail point-of-sale, whe re contamination data originated, and consumption was modelled. The frequen cy and amount of consumption of these foods completed the data for the expo sure assessment. For the hazard characterization or dose response part of t he risk assessment, data from animal studies, virulence assays and epidemio logical investigations were used to estimate the likelihood of illness for different human groups from consuming different numbers of L. monocytogenes . This risk assessment is a virtual review of current scientific knowledge. Quantitative modelling provides greater insight than a qualitative review and also indicates the uncertainty about our knowledge. The risk assessment does not attempt to der ne an acceptable or tolerable level of L. monocyto genes consumption or propose changes in regulations. These decisions are th e responsibility of risk managers who consider additional factors such as f ood preferences, technical feasibility and societal values when evaluating regulatory policies.