A search for the source of Campylobacter jejuni in milk.

Samples of milk from 1501 cows with mastitis were negative for Campylobacter jejuni. The faeces of 74 healthy Friesian cows were screened for C. jejuni: 13% of the samples were positive during the summer when the cows were on pasture, and 51% were positive in the winter when the cows were housed. Positive samples contained on average 1 X 10(4) campylobacters per g faeces. It is concluded that faecal contamination rather than udder infection is the means by which campylobacters enter milk and thereby infect man.