The incidence of Listeria spp. in faeces of Danish pigs and in minced pork meat.

One hundred and seventy-two samples of pig faeces, collected at a slaughterhouse, were investigated for Listeria species. Three of the samples (1.7%) contained L. monocytogenes, while L. innocua was demonstrated in four other samples. The 172 samples represented pigs from 72 herds, 14 (19%) of which were SPF herds. Listeria was not demonstrated in any of the samples from the SPF herds representing 24% of all samples investigated. This indicates that the incidence of L. monocytogenes in SPF herds might be very low. In 51 samples of minced pork, Listeria spp. were demonstrated in 32 samples, L. monocytogenes in six samples, L. innocua in 26 samples, and L. seeligeri in one sample. In comparison with similar findings in cattle faeces and minced beef, the conclusion was drawn that faecal contamination may play an important rôle in the dissemination of L. monocytogenes in raw meats.