Enterobacteriaceae and other bacterial contaminants in refrigerated meat: evaluation and relevance to public health

Abstract

Refrigerated meat is among the most accessible food products for human consumption. Among different types of meat, poultry and pork are most frequently associated with cases of foodborne illness worldwide, often resulting from contamination with zoonotic bacteria. This underscores the critical importance of maintaining high levels of biosecurity throughout the entire production, processing, and marketing chain of poultry and pork meat. Based on the above, the purpose of this research was focused on establishing the presence and diversity of Enterobacteriaceae bacteria in refrigerated meat collected from commercial units of Bălți municipality, Republic of Moldova. The research was carried out on samples of refrigerated poultry and pork meat and for the isolation of bacterial flora, selective and differential cultural media were used for Gram-negative bacteria. Identification was performed by MALDI-TOF method. The analysis of bacterial species distribution isolated from poultry and pork refrigerated meat samples revealed a clear predominance of bacteria belonging to the Enterobacteriaceae family (83%), which indicates enteric contamination, most likely associated with unhygienic handling during slaughtering, a possible deficient processing, or improper storage conditions. The most commonly isolated microorganism was Escherichia coli (25%), followed by Proteus mirabilis (18%), Morganella morganii (10%), Hafnia alvei (6%), and Escherichia albertii (5%). The isolation frequency decreased to 3% for Citrobacter braakii, Klebsiella oxytoca, Moellerella wisconsensis, and Raoultella ornithinolytica. Other sporadically isolated Enterobacteriaceae were Citrobacter amalonaticus, Enterobacter hormaechei, Klebsiella pneumoniae, Providencia rustigianii, Serratia liquefaciens, Proteus vulgaris and Escherichia fergusonii. Regarding non-Enterobacteriaceae species, the most frequent was Aeromonas veronii (11 isolates), followed by Plesiomonas shigelloides (3%), Acinetobacter hemolyticus (2%) and Acinetobacter baumannii (1%). Although major enteropathogenic bacteria were not identified, enteric contamination remains a relevant indicator for food safety, justifying the need for strict hygiene control, modernization of diagnosis, and expansion of monitoring at the national level