Longitudinal Study for the Detection and Quantification of Campylobacter spp. in Dairy Cows during Milking and in the Dairy Farm Environment

Campylobacteriosis outbreaks have repeatedly been associated with the consumption of raw milk. This study aimed to explore the variation in the prevalence and concentration of Campylobacter spp. in cows' milk and feces, the farm environment and on the teat skin over an entire year at a small German dairy farm. Bi-weekly samples were collected from the environment (boot socks), teats, raw milk, milk filters, milking clusters and feces collected from the recta of dairy cows. Samples were analyzed for Campylobacter spp., E. coli, the total aerobic plate count and for Pseudomonas spp. The prevalence of Campylobacter spp. was found to be the highest in feces (77.1%), completely absent in milking equipment and low in raw milk (0.4%). The mean concentration of Campylobacter spp. was 2.43 log(10) colony-forming units (CFU)/g in feces and 1.26 log(10) CFU/teat swab. Only a single milk filter at the end of the milk pipeline and one individual cow's raw milk sample were positive on the same day, with a concentration of 2.74 log(10) CFU/filter and 2.37 log(10) CFU/mL for the raw milk. On the same day, nine teat swab samples tested positive for Campylobacter spp. This study highlights the persistence of Campylobacter spp. for at least one year in the intestine of individual cows and within the general farm environment and demonstrates that fecal cross-contamination of the teats can occur even when the contamination of raw milk is a rare event.

Automated summary

This study investigated the variation in the prevalence and concentration of Campylobacter spp. in cows' milk, feces, and the farm environment over one year at a small German dairy farm. The highest prevalence of Campylobacter spp. was found in feces (77.1%), while it was completely absent in milking equipment and low in raw milk (0.4%). The study highlights the persistence of Campylobacter spp. in individual cows' intestines and the farm environment for at least one year, as well as the possibility of fecal cross-contamination of teats even when raw milk contamination is rare.