Detection and identification approaches of psychrotrophic bacteria in raw milk and dairy products: A review

Milk and dairy products provide an ideal environment for microorganisms due to their rich nutrients. Psychrotrophic bacteria frequently dominate the microflora of raw milk and dairy products during low-temperature storage. These bacteria produce heat-resistant extracellular or intracellular enzymes, primarily proteases and lipases, which cause spoilage and negatively affect product quality and safety. Therefore, the development of rapid, sensitive, and effective detection methods for psychrotrophic bacteria in raw milk and low-temperature dairy products is essential for maintaining quality and preventing economic losses. Traditional detection methods are labour-intensive and require up to 10 days to yield results. In contrast, molecular biology-based methods reduce testing time to a few hours, increase efficiency, and improve sensitivity to approximately 1 log colony-forming unit (CFU)/mL, enabling earlier product alerts. This review systematically compares traditional and emerging detection methods and further discusses advancements in psychrotrophic bacteria detection technology and its practical applications.