Evaluation of hygiene Lighvan cheese aspects regarding Lactococcus garvieae bacteria relying on culture-based and molecular methods

One of the pathogenic bacteria species in the genus of Lactococcus is Lactococcus garvieae. It causes human disease (endocarditis) and mastitis in dairy cows to appear. The presence of these bacteria in the raw milk products like Lighvan cheese was reported. Lighvan cheese is a traditional cheese which is made from raw sheep's milk.In this study, fresh milk, curd, Fresh cheese and ripe cheese, and fresh grass Lighvan area was used to isolate bacteria. Biochemical tests at 10°C and 45°C and grow in salt concentration 4% and 6.5 %, was performed. After extraction of DNA, PCR reaction with primers for genes of Lactococcus 16S rRNA performed and the products were sequenced by the company Source BioScience England, then in gene databases NCBI, the sequence of which more than 97% were similar in terms of genus and species were identified.At first, 1500 colonies similar to Lactococcal genera isolated from different sources such as fresh grass, fresh milk, curd, fresh cheese and ripened cheese according to colony morphology. Then, the 625 isolates were selected by gram stain. The biochemical tests carried out to select 60 isolates of Lactococcal genus and the PCR was used to determine the 16S rRNA gene sequence region to identify species. Based on molecular identification 50 species, were belonged to the Lactococcal genera and finally two species of Lactococcus were Lactococcus garvieae.According to the results, the presence of two species of Lactococcus garvieae (fresh milk and curd) was demonstrated in the early stages of Lighvan cheese production, But, there was no presence of the bacteria in fresh cheese and ripened cheese.