The contamination of paté by Listeria monocytogenes in England and Wales in 1989 and 1990.

In July 1989, 1834 samples of paté (of which 1698 were from retail displays) were examined by the PHLS for the presence of Listeria monocytogenes. The survey was repeated in July 1990, when 626 paté samples on retail sale were examined. Between the two surveys there was a marked reduction in the proportions of patés contaminated (10% in 1989 and 4% in 1990) and in the numbers of samples from which > 10(3) L. monocytogenes/g were recovered. The higher rate of contamination detected in 1989 was largely due to paté from a single manufacturer. In both surveys, paté sold as loose slices had higher rates of contamination than those prepackaged. Temperature control had improved between the two surveys where 65% of samples in 1989 and 83% in 1990 were stored at < or = 7 degrees C. Although contamination occurred at almost all temperatures, L. monocytogenes was both quantitatively and qualitatively more common in samples stored at > 7 degrees C. The majority of patés had unexpired shelf lives of between 0 and 3 weeks. Although contamination occurred throughout the shelf life of these products, the proportion of samples where L. monocytogenes was recovered was higher in patés with expired sell by dates. There was an association between high total viable counts and the presence of L. monocytogenes. Likely routes of contamination of paté together with possible preventive measured are discussed.