The Microbiology of Cheese and Dairy Products is a Critical Step in Ensuring Health, Quality and Typicity

Cheese and dairy products require a rigorous observation of the procedures, strictly linked to the different indigenous components, such as the initial raw materials, the process chain, the ripening temperature, the water activity (aw), the pH and the contamination of the environment and operators. Microorganisms are key agents in the transformation of milk and in the subsequent phases which confer typicity and stability to cheese and dairy products. Contamination by pathogenic microorganisms may occur, compromising the safety of the final products. Meanwhile, beneficial microorganisms present in cheese and dairy products can produce antimicrobial compounds, thus avoiding spoilage of the products, ensuring their safety for human consumption. This mini review reports a description of the microorganisms involved in the fermentation of milk and in the subsequent processes concerning cheeses and derivatives, highlighting the aspects that microorganisms play in terms of quality, typicality and safety. New aspects emerged from this study, suggesting possible insights and future research. These include cultural approaches on the one hand, which allow for the isolation and characterization of new microbial strains that confer peculiarities in terms of quality and typicality to cheeses and dairy products, and the isolation of lactic acid bacteria that produce bacteriocins as important tools for combating microbial pathogens. On the other hand, investigations on cheese and dairy products using metagenomic approaches with DNA extraction followed by amplification and sequencing of microbial genes, allow the description and monitoring of the entire microbiota involved in the transformation processes of cheese and dairy products. Therefore, the combination of cultural dairy microbiology and metagenomic approaches can lead to improving the characteristics of cheeses and dairy products, while maintaining respect for traditions.