The occurrence in the U.K. of Listeria species in raw chickens and soft cheeses

Abstract

Retail samples of 100 raw chickens and 222 U.K. and imported soft cheeses were examined for the presence of Listeria species. 60% of raw chickens (fresh and frozen) were contaminated with L. monocytogenes and 28% with other Listeria spp. including L. welshimeri, L. seeligeri and L. innocua. Six serotypes of L. monocytogenes were represented (1/2, 3a, 3b, 3c, 4b, 4d) of which more than one were isolated from some samples. 10% of the soft cheeses examined were found to contain L. monocytogenes at levels from less than 10(2) cfu/g to 10(5) cfu/g. The incidences in cheeses from various countries were Italy (16%), France (14%), Cyprus (10%) and the U.K. (4%). Only 2 serotypes (1/2 and 4b) were isolated, some samples containing both. L. innocua was the only other Listeria sp. found. There was no correlation between either the contamination with E. coli or the processing of the original milk used to make the cheeses (raw or pasteurized) and the presence of L. monocytogenes or other Listeria spp. The contribution of contaminated food to the epidemiology of listeriosis in the U.K. is discussed.