Gene Detection and Enzymatic Activity of Psychrotrophic Bacillus cereus s.s. Isolated from Milking Environments, Dairies, Milk, and Dairy Products

<i>Bacillus cereus</i> is a spore-forming, Gram-positive bacterium that causes foodborne illness and dairy spoilage. This study analyzed <i>B. cereus s.s.</i> isolates from milking environments, raw milk, and dairy products to assess their genotypic and phenotypic traits. From 466 samples, 61 isolates were obtained: 27 from milking environments, 9 from dairy environments, 8 from raw milk, and 17 from dairy products. Genomic sequencing identified genes encoding proteolytic (BC5350, BC0666, BC2984, BC0598, BC5351, BC3383, BC2735), lipolytic (BC4862, BC2141, BC1027, BC4123, BC4345, BC5402, BC5401), and esterase (BC1954, BC4515, BC3413, BC3606) enzymes. Plate assays confirmed enzymatic activities. Proteolytic genes were more prevalent in environmental samples, followed by raw milk and dairy products. Lipolytic genes were most frequent in raw milk, followed by environmental samples and dairy products. Esterase genes were most common in dairy environments. These findings suggest that dairy processing influences the enzymatic profile of <i>B. cereus s.s.</i>, potentially impacting food safety and quality in the dairy industry. Understanding the distribution of these genes may help develop strategies to mitigate spoilage and contamination risks in dairy products.