7. Gaps in current knowledge on the incidence of L. monocytogenes in fishery products

• There is a need to estimate accurately the risk of listeriosis due to fishery products, and to identify appropriate risk-mitigation and control strategies.
• There is a need for epidemiological data on the role of fishery products in listeriosis to assess the validity of any risk assessments undertaken.
• New data are required on the dose-response relationship for L. monocytogenes. A better understanding of the role of host susceptibility factors and virulence factors of the organism is also required to complement the dose-response information.
• There is a need to investigate the use of Listeria species as an indicator of the presence of L. monocytogenes for in-plant environmental monitoring programmes.
• Predictive models are able to generate data on the growth rates of L. monocytogenes inoculated onto products. Information on the ecology of L. monocytogenes on naturally contaminated products is required to determine the amount of growth likely within their recommended 'use-by-date' and at the recommended storage temperatures. Specifically, data concerning the influence of cell injury and competitive flora are required.
• For exposure assessment, more data concerning contamination levels on products and frequency of contamination, geographical distribution and information on the integrity of the chill-chain for fishery products are required. Consumption pattern data, and data concerning production volumes should also be collated and integrated with the risk assessment. In particular, there is a lack of data for tropical regions and their fishery products.
• Information is required on how the organism becomes established in the fish processing environment and methods for its prevention/elimination.
• Information is required on the trade impacts of L. monocytogenes in fishery products and the benefits and costs of different criteria and sanitary and phytosanitary measures.