Food Safety
Online ISSN : 2187-8404
ISSN-L : 2187-8404
Risk assessment report: Microorganisms and Viruses
Listeria monocytogenes in foods
Executive Summary

2014 Volume 2 Issue 1 Pages 5-8


The Food Safety Commission of Japan (FSCJ) conducted a risk assessment of Listeria monocytogenes (LM) in ready-to-eat (RTE) foods contaminated with LM. Data used for the assessment were those of food intake, the susceptible people population, estimated incidence of human listeriosis, and LM contamination in RTE foods in Japan. Contamination levels of LM in RTE foods and exponential dose-response model described in the evaluation report of Joint FAO/WHO Expert Meetings on Microbiological Risk Assessment (JEMRA) were also used for the assessment. The result of the assessment shows that if the contamination level of LM in RTE foods is below 10,000 CFU/g at consumption, the number of invasive listeriosis cases would be lower than those (200 cases) calculated from data of surveillance conducted by the Ministry of Health, Labour and Welfare. Therefore, the development of invasive listeriosis in Japan is likely caused by consumption of foods contaminated with LM at a level higher than 10,000 CFU/g. Furthermore, the result indicates that if some foods are contaminated with such an extremely high level of LM as 1,000,000 CFU/g at consumption, the number of patients would increase with the increase in the proportion of such heavily contaminated foods even when contamination levels in foods are relatively low as a whole. Therefore, to reduce the incidence of listeriosis, it is necessary to decrease the frequency of occurrence of foods contaminated heavily with LM by specifying a storage period for RTE foods. Manufacturers and processors of RTE foods should implement end product testing on LM, good hygienic practices, and environmental monitoring for LM in their plants.

© 2014 Food Safety Commission, Cabinet Office, Government of Japan
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