Bacterial consortia of ewes' whey in the production of bryndza cheese in Slovakia.

Whey from previous production is often used as a natural starter in the technology of traditional cheeses, including bryndza cheese in Slovakia. Therefore, studying its bacterial community and isolating new potential natural starters is important for improving the characteristics of the final product. Composition of bacterial consortia of fresh and fermented whey in the production of raw ewes' milk-based bryndza cheese from 8 small or medium-sized producers was analysed. Culture-based microbiological analysis and culture-independent analysis based on 16S rRNA gene sequencing by MiSeq and MinION were used. Results showed the dominance of lactococci or streptococci, with 3-8 log CFU ml-¹ of Lactobacillus sensu lato in all whey samples. Potential natural starters comprising Lacticaseibacillus paracasei/casei, Lactiplantibacillus plantarum, Lentilactobacillus parabuchneri, Lactobacillus helveticus, L. diolivorans, Levilactobacillus brevis, Limosilactobacillus fermentum, L. delbrueckii, L. gasseri and L. otakiensis were isolated. Coliforms were also present in all samples, with no consistently lower values in fermented whey samples. Some samples contained pseudomonads and/or acinetobacters. Coagulase-positive staphylococci were present at relevant levels in samples from 4 producers. The results revealed that whey is a source of natural starters due to the presence of lactobacilli.