Clinically Relevant Campylobacter jejuni Subtypes Are Readily Found and Transmitted within the Cattle Production Continuum but Present a Limited Foodborne Risk

Limited information is available on the transmission of Campylobacter jejuni subtypes in the beef production continuum and the foodborne risk posed to humans. Cattle were colonized by diverse subtypes of C. jejuni , and the densities of the bacterium shed in feces increased during the confined feeding period. Campylobacter jejuni was readily associated with the digesta, feces, and hides of cattle entering the abattoir, as well as the local environment. Moreover, C. jejuni cells were deposited on carcasses via direct contact and aerosols, but the bacterium was not detected in the ground beef generated from contaminated carcasses. We conclude that C. jejuni bacterial cells associated with beef cattle do not represent a significant risk through food consumption and suggest that clinically relevant subtypes are transmitted through alternate routes of exposure.