Proposal P239 - Listeria - Risk Assessment & Risk Management Strategy
20 November 2002
FINAL ASSESSMENT REPORT
Full Report [ pdf 612 kb ]
Executive Summary and Statement of Reasons
Listeria monocytogenes in certain food categories poses a potential public health and safety problem, especially for vulnerable sub-populations such as pregnant women and the elderly. While the incidence of systemic infection caused by L. monocytogenes in food is low, the consequences can be severe and include death. Risk assessments were undertaken examining the public health impact of L. monocytogenes in cooked crustacea and ready-to-eat processed finfish.
The risk assessment concluded that there is a very low likelihood of Listeriosis in vulnerable populations that would be linked to exposure to L. monocytogenes in cooked crustacea (estimates indicate a mean annual case rate in Australia of one case of Listeriosis for every 1,600 years). While the residual risk could be managed by mandating a microbiological limit for L. monocytogenes in cooked crustacea , it is unlikely to be an effective risk management measure, because the probability of identifying contaminated product from limited samples and preventing exposure before the food is sold and consumed is low. This conclusion was based on the observation that the frequency of contamination of cooked crustacea appears to be low (approximately 3%) and that the product has a short shelf life. Microbiological limits that serve to ensure good hygienic practices associated with food already exist in the Volume 2 of the Food Standards Code (Code), thereby encouraging appropriate practices, such as temperature control, in the processing and storage of cooked crustacea. It was concluded that the current microbiological standard for L. monocytogenes in cooked crustacea in Volume 2 of the Code cannot be justified on basis of public health and safety and effectiveness and should be deleted.
The risk assessment for L. monocytogenes in ready-to-eat processed finfish (such as cold smoked salmon) concluded that this pathogen/commodity combination posed a significant risk to health and safety, especially to the susceptible sub-populations. This conclusion was based on the observations that this food supports the growth of the pathogen that there is no kill step in the processing of this product and, together with the long shelf life of the product, growth of L. monocytogenes to levels significant for public health can occur. An evaluation of alternative regulatory requirement for ready-to-eat processed finfish compared the public health outcomes achieved by the existing Standard 1.6.1 (which allows one in five samples from a batch to contain no more than 100 cfu/g of L. monocytogenes) and a hypothetical zero tolerance standard. It was concluded that there would be no significant difference between the two measures in terms of public health outcomes. The Draft Assessment concluded that a microbiological standard in Volume 2 of the Code for L. monocytogenes for ready-to-eat processed finfish could be justified and that the current standard is a minimum effective and achievable measure that protects public health and safety. More stringent changes to the standard for L. monocytogenes in ready-to-eat processed finfish could not be justified on the basis of findings in the risk assessment and evaluation of an alternative measure.
The Draft Assessment report proposed that:
- The standard for cooked crustacea of absent in 25 g for 5 samples from a batch should be deleted.
- The standard for ready-to-eat processed finfish e.g. cold smoked salmon, which permits one in five samples to have a count up to 100 cfu/g should be retained.
These recommendations were supported by public submissions received at Final Assessment.
Statement of Reasons
An amendment to Standard 1.6.1 of Volume 2 of the Code to delete the microbiological limit for L. monocytogenes in cooked crustacea is recommended because the existing measure cannot be justified on public health grounds and its deletion will not adversely affect public health and safety.
It is recommended that the microbiological limit for L. monocytogenes in ready-to-eat processed finfish in Standard 1.6.1 of Volume 2 of the Code be retained because it can be justified on public health grounds and the current measure will provide adequate level of public health and safety protection and be achievable.
Full Report [ pdf 612 kb ]