Detection in raw cow's milk of coliform bacteria - reservoir of antibiotic resistance

Antibiotic resistance is one of the main threat for people, especially since food products are more frequently identified as a reservoir of antibiotic resistance genes. Thus, the aim of the study was to analyse the Polish raw cow's milk in terms of the presence of coliform bacteria resistant to antibiotic as well as to identify volatile compounds (VC) characteristic for such bacteria. Further, the identified profile of VC could be used in development of coliform bacteria detection method directly in the product. The obtained data showed that among coliform bacteria strain isolated from Polish raw cow's milk 88% were resistant to penicillin, 39% to kanamycin, 43% to streptomycin, 78% to chloramphenicol and 55% to tetracycline. Moreover, tetM gene, frequently connected with mobile genetic elements, were detected in 42% of isolated coliform strains. Due to widespread of coliform bacteria resistant to antibiotic in raw milk, simple methods of detection of coliform bacteria in such product are required. Performed analysis suggests that lack of methional might be used as an indicator of raw cow's milk contamination with coliform bacteria.