Neli Ermenlieva, Sylvia Stamova, Sevginar Ibryamova, Nadezhda Ivanova, Petya Atanasova, Velichka Marinova, Gabriela Tsankova, Emilia Georgieva
The results demonstrate that artisanal white brined cheese is not inherently associated with a higher microbiological risk when good manufacturing and hygienic practices are applied. More importantly, the study shows that combining foodborne pathogens, hygiene indicators, and indigenous yeast microbiota provides a substantially more comprehensive assessment of microbiological quality than pathogen detection alone, supporting an integrated concept for the evaluation of traditional fermented dairy products.
BACKGROUND: White brined cheese represents one of the most important traditional fermented dairy products in Bulgaria. Its microbiological quality is commonly evaluated through the detection of foodborne pathogens; however, such an approach provides limited information regarding production hygiene and the natural microbial ecosystem of the product.
METHODS: The present study performed an integrated microbiological assessment of 100 Bulgarian white brined cow's milk cheese samples (50 artisanal and 50 industrial) by simultaneously evaluating hygiene indicator microorganisms (Escherichia coli and coagulase-positive staphylococci), major foodborne pathogens (Listeria monocytogenes and Salmonella spp.), and the natural yeast microbiota using standardized ISO methods. Yeast species were identified by MALDI-TOF MS, and statistical analyses were performed using Fisher's exact test and the Mann-Whitney U test.
RESULTS: Listeria monocytogenes, Salmonella spp., and coagulase-positive staphylococci were not detected in any cheese sample. Escherichia coli was detected in only two samples (2.0%), with no significant difference between artisanal and industrial cheeses (p > 0.05). In contrast, yeasts were detected in 99% of the samples, and nine yeast taxa were identified. Significant differences in yeast species distribution were observed between production systems, with Torulaspora delbrueckii predominating in artisanal cheeses and Debaryomyces hansenii in industrial products (p < 0.001).
CONCLUSIONS: The results demonstrate that artisanal white brined cheese is not inherently associated with a higher microbiological risk when good manufacturing and hygienic practices are applied. More importantly, the study shows that combining foodborne pathogens, hygiene indicators, and indigenous yeast microbiota provides a substantially more comprehensive assessment of microbiological quality than pathogen detection alone, supporting an integrated concept for the evaluation of traditional fermented dairy products.