Evaluation of the bacterial composition of sour cream using high-throughput sequencing

Lactic acid bacteria are actively used as starter cultures for various food products, including dairy products. The quality of the final product often depends on the quality of the starter culture. Sour cream is a traditional product in many countries. Its production is based on the fermentation of cream with the addition of certain types of starter cultures belonging to the genera Streptococcus, Lactobacillus, Lactococcus, Pediococcus and Enterococcus. Using the method of high-throughput sequencing, the bacterial compositions of sour cream samples from various manufacturers available on the Russian market were investigated. Sequencing was performed on an Illumina MiSeq platform. Bacterial taxa were taken into account, whose percentage exceeded 1% relative to all identified microorganisms in the sample. As a result of the analysis, it was found that the dominant bacteria in all samples of 20% sour cream were representatives of the genera Streptococcus and Lactococcus. Samples No. 3 and No. 10 contained Lacticaseibacillus. Their percentage in these samples did not exceed 2%. In sour cream sample No. 1, representatives of the genus Enterococcus were identified (3% of the total number of bacteria found in the sample). Species analysis of the microbial community of the studied samples using the Nucleotide BLAST system made it possible to determine that Lactococcus lactis, Streptococcus thermophilus, Lacticaseibacillus rhamnosus (sour cream numbers 3 and 10) and Enterococcus faecium are probably used as starter cultures. These bacteria are traditionally used in the production of fermented dairy products due to the ability to form specific tastes, aromas and textures during fermentation.