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The European Food Safety Authority and its Task Force on Zoonoses Data Collection were requested by the European Commission to produce a proposal for technical specifications on a co-ordinated monitoring programme (a survey scheme) for Listeria monocytogenes in ready-to-eat (RTE) food. This survey should allow the comparison of L. monocytogenes contamination in RTE food in the Community and Member States and the verification of the Community food safety criteria for L. monocytogenes.
The proposed technical specifications focus on sampling those categories of RTE food in which the highest rates of L. monocytogenes contamination have been observed in the European Union (EU): soft and semi-soft cheeses, smoked and gravad fish, and heat-treated meat products that are handled after heat treatment. Two alternatives for an EU wide survey on L. monocytogenes in RTE food are proposed. The first option consists of 27 Member State-specific surveys (Member States’ specific surveys) and would allow both the L. monocytogenes prevalence in each Member State as well as at the Community level to be determined. In this option it is proposed that two RTE food categories would be covered by the survey, i.e. soft and semi-soft cheeses and smoked and gravad fish. The heat-treated meat products could be addressed at a later stage by another optional survey round.
The second option is a Community-specific survey that would only allow estimation of the L. monocytogenes prevalence at the Community level. This proposal requires a Community-specific number of samples to be allocated amongst the Member States in proportion to the size of their human populations resulting in a reduced number of samples to be taken at the Member State-level. This enables the inclusion of a third RTE food category (heat-treated meat products) in the survey as well as the inclusion of the detection method for L. monocytogenes.
Sampling of the RTE food categories would be targeted at retail outlets serving the final consumer, with catering and wholesale establishments excluded. A survey undertaken at retail will assess the effectiveness of the implementation of Community L. monocytogenes criteria. Such a survey would also provide information to assess the exposure of consumers via these RTE food categories. Food products are suggested to be tested at the end of the shelf-life and additionally in the case of smoked and gravad fish, immediately after sampling. In addition, water activity and pH values are to be measured in the smoked and gravad fish. It is envisaged that the competent authorities in the Member States would construct a sampling plan for the retail sampling in their country.
Standardised analytical methods are proposed to be employed in the analyses of samples. It is recommended that the enumeration method is used to obtain quantitative information on L. monocytogenes in the RTE food categories. In addition, in the Community-specific survey the detection method would be used. Isolates of L. monocytogenes are suggested to be archived for the purpose of future typing.
It is intended that a modelling and simulation approach be applied in the analyses of the results so that the effectiveness of the implementation of Community L. monocytogenes criteria may be assessed. A similar model-based approach will also be used to estimate the growth potential of L. monocytogenes in smoked and gravad fish.