关键词: 关键词:原料乳, 耐热性微生物, 颗粒析出, 过氧乙酸, 高通量测序

Abstract: Abstract: With the increasing demand for liquid milk, its quality and safety have become particularly important, and the presence of heat-resistant microorganisms is one of the reasons that cannot be ignored for the defects in its quality. Therefore, this article takes heat-resistant microorganisms isolated from raw milk as the research object, uses high-throughput sequencing technology to explore the diversity of raw milk microorganisms, and uses pure culture and 16S rDNA sequencing to isolate and identify heat-resistant microorganisms，analyzes their biodiversity and morphological characteristics. Subsequently, a reverse reaction test was conducted on the identified heat-resistant microorganisms to simulates the spoilage process of products contaminated with this microorganism in normal sterilized milk and skim milk, as well to study the tolerance of microorganisms, in order to provide screening and control strategies for dairy products with abnormal conditions. The results showed that the heat-resistant microorganisms in the raw milk were mainly Bacillus, and three special forms were mainly discovered through Gram staining; Particle precipitation and stratification phenomena occur after inoculation of different types of Bacillus subtilis into sterilized milk; After inoculation of different types of Bacillus subtilis into skim milk, the color turns yellow and the taste becomes bitter; Bacillus subtilis has strong temperature tolerance but poor tolerance to peracetic acid. Enterprises can verify that using a certain concentration of peracetic acid disinfectant combined with CIP cleaning program can effectively kill residual heat-resistant microorganisms on the production line.

Key words: KEY WORDS: Raw milk, Heat-resistant microorganisms, Particle precipitation, Peracetic acid, High-throughput sequencing