Antibiotic resistance of raw-milk-associated psychrotrophic bacteria.

The present study proposed to evaluate the breadth of antibiotic resistance among psychrotrophic bacteria spoiling raw milks in Finland. A core of 60 isolates, retrieved from farms, trucks, and silos, phenotypically characterized, were analysed with ATB PSE strips, composed of a panel of 17 beta-lactams and non-beta-lactams antibiotics, representatives of five classes. Surprisingly, 60% of the psychrotrophs harboured multiresistant traits. We observed an increase of this feature along the cold chain of raw milk transportation.