The rules that govern international trade are those agreed on during the Uruguay Round of Multilateral Trade negotiations and apply to Members of the WTO. With respect to food safety matters, those rules are set out in the Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement). The overall objective of the SPS Agreement is to permit countries to take legitimate measures to protect the life and health of their consumers while prohibiting them from using measures in a way that unjustifiably restrict trade. Thus, the primary role of the SPS Agreement is to limit the use of any measures that may restrict trade to those that are justified and necessary to provide the appropriate level of health protection.

In the case of human health, the standards, guidelines and other recommendations of the Codex Alimentarius Commission (CAC) are considered by the WTO to reflect the international consensus regarding the requirements for protecting human health. When there are no specific international standards, sanitary and phytosanitary measures may be introduced provided there is a scientific justification based on a risk assessment appropriate to the circumstances and transparency and consistency are maintained. The same provisions apply if Members introduce measures to protect human health that provide a higher level of protection than would be achieved by international standards, guidelines and recommendations. As for most other foodborne pathogenic bacteria, no international specific standards or recommendations exist for L. monocytogenes.

The globalization and growth of international trade in fish and fishery products in recent years has made these products one of the most important items traded in terms of value. This situation has prompted the emergence of a number of new regulations based on perceived or real concerns about the possible distribution of microorganisms or their toxins that could affect the health of consumers.

L. monocytogenes, and other Listeria species, have been isolated from fishery products on a regular basis since the late nineteen eighties. However, the available data indicates wide differences in the geographic distribution or prevalence in different types of products. Its relatively high incidence in ready-to-eat and heat-treated fishery products has raised concerns about the survival and growth potential of the organism in such products, as they are not processed further before consumption. L. monocytogenes has not been associated with a large outbreak of listeriosis due to the consumption of contaminated fishery products. However, at least three sporadic documented cases have been reported in the early nineteen nineties and more recently, "gravad" trout and smoked trout have been linked to a small outbreak of listeriosis.

Several countries have a zero-tolerance policy for L. monocytogenes in foods, including fishery products. This can be applied to all foods or only high-risk food items that support growth of the organism. It can also be applied to foods with a history of being implicated in listeriosis outbreaks. Following several product recalls it appears that the presence of L. monocytogenes in fish and fishery products may have severe economic consequences for producers. Considering the current knowledge of Listeria and listeriosis, a zero-tolerance policy for all ready-to-eat fishery products may be overly conservative relative to providing an adequate level of public health protection. Zero-tolerance policies for products that do not undergo any listericidal process steps seem to be in contradiction with new modern regulations for fishery products. These regulations are all based on the use of HACCP principles which recommend the use of risk assessment in identifying and controlling hazards, thus establishing maximum limits rather than zero-tolerance. In recent years, other countries have acknowledged this and have introduced regulations allowing maximum limits on the content of L. monocytogenes in foods. The range of these limits varies between 10 colony forming units (cfu)g-1, to 100 cfu g-1 or 1000 cfu g-1 depending on the products, their risk category and time of consumption. However, in the case of Listeria contamination of fish, there is still need for a more complete assessment of the risk and the implications on international fish trade. The present consultation addressed these points.