Microbiological Evaluation and Genetic Identification of Some Bacterial Species in Soft Cheeses: Implications for Food Safety

This study investigates the microbiological profile of soft cheeses in Egypt, focusing on the identification of Kocuria flava, Bacillus licheniformis, Bacillus subtilis, and Escherichia coli. A total of 100 cheese samples were analyzed, and bacterial isolates were characterized using 16S rRNA gene sequencing, with sequences registered in GenBank. Phylogenetic analysis confirmed that the isolates belonged to the genera Escherichia, Bacillus, and Kocuria, closely resembling known strains of E. coli, B. licheniformis, K. flava, and B. subtilis. Cluster analysis and phylogenetic tree construction revealed genetic similarity with reference strains, with the isolates segregated into two distinct clusters. Microbiological evaluation demonstrated significant variation in bacterial counts (cfu/g) across cheese types. Salmonella was detected in higher concentrations in Istanbolly and Tallaga cheeses compared to Kariesh and Feta cheeses. B. licheniformis exhibited higher counts in Tallaga, Feta, and Kariesh cheeses than in Istanbolly. E. coli was most abundant in Istanbolly cheese, followed by Tallaga and Kariesh, with the lowest levels in Feta cheese. B. subtilis showed the highest counts in Feta cheese, while K. flava was predominantly found in Istanbolly cheese. These findings highlight the potential presence of harmful microorganisms in soft cheeses, underscoring the importance of stringent hygiene practices during production. Regular microbial assessments and monitoring protocols are essential to detect spoilage bacteria, mitigate health risks, and enhance food safety standards, ensuring the safety of these widely consumed dairy products.