Microbial profiling of artisanal goat milk and cheese: Insights into virulence traits, metabolic activity, and biofilm formation.

Abstract

This study provides a comprehensive phenotypic and genotypic characterization of bacterial isolates from traditionally produced goat cheese and raw goat milk, with a focus on attributes relevant to food safety and public health. The isolates exhibited substantial physiological and metabolic diversity, notably in carbohydrate fermentation patterns and proteolytic activity. While Escherichia coli strains typically demonstrated complete sugar fermentation, Proteus mirabilis and Pseudomonas spp. were characterized by proteolytic metabolism and, in some cases, hydrogen sulfide production. Molecular analysis identified virulence genes (stx1, stx2, hlyA) in several E. coli isolates, although the eaeA gene was absent. Hemolytic activity (α- and β-hemolysis) was detected in opportunistic species including P. mirabilis, Pseudomonas spp., and Raoultella aquatilis, reinforcing their pathogenic potential of this. Importantly, no isolates produced histamine from histidine, suggesting a lower risk of biogenic amine formation and associated food safety concerns. Biofilm formation, a critical factor in microbial persistence and resistance to sanitation, was influenced by temperature and time, with notably stronger biofilms at 37 °C. Strains such as Enterobacter cloacae GC-2 and E. coli GC-40 consistently demonstrated high biofilm-forming capacity, indicating their potential to survive in dairy processing environments. These results highlight significant microbiological risks in minimally processed artisanal dairy products and underscore the need for targeted preventive controls. Implementing integrated microbial monitoring, combining phenotypic assessment with molecular diagnostics, can improve the detection of foodborne pathogens and spoilage organisms. Such strategies are essential for enhancing the microbiological safety and quality of traditional dairy products, ultimately supporting public health protection.