Microbial biodiversity of traditional cheeses and natural dairy environments as drivers of food innovation

In this study, we focused on enhancing the microbial biodiversity that characterizes traditional dairy productions and environments as a key driver for food innovation. As part of an extensive sampling effort, including raw milk, curds, natural whey cultures, and different cheeses at different ripening stage or cold storage, more than 140 microbial isolates were preliminarily evaluated, resulting in a collection of 98 bacterial strains. Among these, 28 strains were selected for their possible application in milk processing. The research for technological traits in strains, belonging to Streptococcus thermophilus, Enterococcus faecalis, Ent. gallinarum, Lacticaseibacillus paracasei, Limosilactibacillus fermentum, Lactococcus garviae, Lact. lactis species, led to the identification of 3 strains with high production of γ-aminobutyric acid (GABA). In parallel, microbial biodiversity related to yeasts and filamentous fungi, allowed the collection of 168 strains. Proteolytic and lipolytic activities as well as the ability to grow on sugar-free and minimal medium “cheese like” substrates interested 19 non-toxigenic Penicillium strains. Competitive interaction assays against a ochratoxigenic Aspergillus westerdijkiae strain from cheese surfaces, guided the selection of promising strains from P. charlesii, P. copticola, P. solitum, P. canescens, P. flavigenum and P. biforme species. These strains demonstrated the potentiality to control the growth of the toxigenic species, thereby contributing to the safety of the ripening process while preserving the typical characteristics of the cheese and its deep connection to the traditional natural environment. Throughout the exploitation of microbial biodiversity from dairy samples, a GABA-producing bacterial starter and a fungal formulate for the secondary ripening of long-aged pasta filata cheeses were defined. Consequently, the production of a new functional cheese and the improvement of the secondary ripening of Caciocavallo cheese in natural caves were carried out.