Biotechnological and Health Potential of Wild Non-Starter Lactic Acid Bacteria Isolated from Italian Traditional Malga-Cheese

Malga-cheese is made only in summer season from raw cow’s milk without addition of starter cultures, in small scale on-farm plants called “Malga”. The typical Malga is located at least 1400 meters above the sea level in alpine region of North Italy. The aims of the research activity were to characterize lactic acid bacteria (LAB) isolated at the end of cheese ripening and to screen them for technological and healthy properties in order to evaluate their potential use in dairy applications. Ninety-five non-starter lactic acid bacteria (NS-LAB) were isolated from Malga-cheese at seven months ripening and genotypically characterized combining Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR), species-specific PCR and partial sequencing of 16S rRNA gene. After RAPD-PCR the 95 analyzed NS-LAB were grouped in 70 biotypes. The dominant species were Pediococcus pentosaceus (32 isolates) and Lactobacillus paracasei (27 isolates). One phages-free strain representative for each biotype was selected to be subjectes to the following assays: diacetyl production, amino-peptidase activity, biogenic amines (BA) production, bile salts hydrolase (BSH) activity, coniugated linoleic acid (CLA), and γ-Aminobutyric acid (GABA) production. Three Lb. parabuchneri biotypes were histamine producers and no isolate showed ability to produce putrescine or cadaverine. Lb. paracasei biotypes were the best diacteyl producer. Four biotypes showed BSH ability. Only two Lb. paracasei biotypes had good amino-peptidase activity toward leucine. These two Lb. paracasei together with a Lb. rhamnosus and 2 Pc. pentosaceus biotypes showed also a good CLA production from LA. Fifteen biotypes were able to produce GABA amounts higher than 5 mgL-1 ; a Lb. plantarum strain was the best GABA producer. This work confirmed that the microbiota present in wild environment and spontaneously fermented food is a potential source of lactic acid bacteria to be exploited as enrichment in health-promoting dairy product