Influence of microbiological risks associated with spore-forming microflora on the quality and storability of butter from different production methods

The article presents the results of studies of the effect of spore-forming bacteria on the quality and storability of butter depending on the method of its production  — cream churning (CC) or high-fat cream transformation (HFCT). A simulation approach was used in conducting the research, including the following stages: reduction of microbial contamination of raw cream and its contamination with a test culture of spore-forming microorganisms; production of butter according to existing technological schemes; control over the development of the test culture at the stages of production and storage of butter. The objects of the study were: cream before and after pasteurization; pasteurized cream contaminated with a test culture of Bacillus subtilis; butter made by CC and HFCT from contaminated cream. Storage of butter samples was carried out at temperatures of 3±2 °C, 10±1 °C and 25±1 °C. The quality and storability of butter were assessed taking into account significant rejection criteria reflecting the requirements of standardization documents. For this purpose, microbiological and physicochemical indicators were determined using standardized methods, including the content of vegetative cells and spore forms of the Bacillus subtilis test culture, milk plasma acidity, and indicators of oxidative spoilage of the fat phase. Organoleptic indicators were assessed by taste, smell, consistency, and appearance. As a result of the studies, it was established that during the production and storage of butter, the greatest microbiological risks associated with spore-forming bacteria of the genus Bacillus and leading to a decrease in its quality and storability were observed during production by the churning method, which is due to the technological features of production (duration of processes, temperature conditions). When producing butter using the HFCT method, the risks associated with spore-forming aerobic microorganisms were less significant. This ensures long-term preservation of the initial safety and quality indicators of butter at a regulated temperature of 3±2 °C, as well as higher storability at elevated storage temperatures in comparison with butter produced using the churning method.