Prevalence and characterisation of Salmonella in slaughtered cattle and beef in Poland

A total of 1229 samples, including 406 bovine hides and 406 corresponding carcasses at the slaughter level, as well as 417 beef meat from local supermarkets, were tested for the presence of Salmonella sp. Eighteen (1.5%) samples were positive for the target microorganism, and the highest prevalence (2.2%) was found in meat, followed by carcasses (1.2%) and hides (1.0%). Among the isolated strains, Salmonella enterica serotypes Enteritidis (six isolates) and Schleissheim (six strains), followed by Dublin (four contaminated samples) were the most predominant. The antimicrobial resistance analysis against nine antimicrobials with the MIC technique revealed that most isolates were sensitive to all antibacterial agents. However, one S. Typhimurium of carcass origin was multidrug resistant, and displayed the resistance to four antimicrobials, i.e. ampicillin, streptomycin, tetracycline, and sulphametoxazole. Furthermore, one S. Enteritidis (from carcasses), two S. Dublin (of beef origin), and one S. London (from meat) strains were resistant to sulphametoxazole. The restriction enzyme analysis with XbaI resulted in eight different PFGE types. The obtained results suggest that cattle may be an underestimated source of pathogenic Salmonella for consumers.