Controlling Listeria monocytogenes in ready-to-eat foods: Working towards global scientific consensus and harmonization – Recommendations for improved prevention and control

An international group of experts from the food industry, academia, and governments met in Amsterdam in May 2009 to discuss approaches for controlling Listeria monocytogenes in ready-to-eat (RTE) foods in anticipation of an agreement by Member States on the Codex Guidelines for the pathogen in foods. The workshop was organised by Ewen Todd (Michigan State University) in cooperation with the European Federation of Food Science and Technology and the Global Harmonization Initiative. The group felt there is a need for a risk-based policy with input from all the stakeholders at local and national levels. An important part of the background is to review the critical factors for control, including the unique growth, survival and virulence characteristics of the pathogen; identifying specific populations at risk; and defining what RTE foods are. They also saw the need for L. monocytogenes food-source attribution through review of outbreak data, implementation of case–control studies, expert elicitations, microbial source tracking, and development of risk assessment models. They also indicated that surveillance of both listeriosis and the gastrointestinal non-invasive form of illness caused by the pathogen are important for public health agencies to establish or enhance; this would require coordination of laboratories through better communication and reporting for the analysis of clinical cases, foods and environmental sources. These laboratories should be also accredited, with some being reference laboratories at national or regional levels. There was consensus agreement on the microbiological criteria as specified in the Codex Guidelines, but it was recognized there were challenges for industry to meet these and government agencies to assess compliance, requiring a robust testing regime for both food and food-contact surfaces at all stages in the production system, as well as for environmental monitoring. Other issues are the development, validation, and acceptance of quantitative methods sufficient to detect the pathogen in food at levels <100 CFU g−1; determining the food’s ability to support the growth of the pathogen or not through challenge studies, and risk assessment models, appropriate labelling of RTE foods, and a standardized approach to tracing and tracking of products throughout the food chain. There is also a need for food worker education and training, and consumer awareness and responsibility. Message mapping is one approach to instill the essential food safety messages regarding listeriosis and the safety of RTE foods for both employees and the public.