Investigation of microbiyota of traditionnaly produced mihalic cheese by MALDI TOF MS and 16S rDNA sequencing

Composition and diversity of lactic flora of Mihalic cheese was evaluated by using comparative analysis of MALDI-TOF MS and 16S rDNA sequencing of isolates. A total of 53 cheese samples were collected from Gönen, Savaştepe, Havran, Manyas, Karacabey provinces of Marmara Region where Mihalıç is produced largely in Turkey. In the first part of the study, the whole lactic flora was analyzed by planting the bacteria on specific media. In general, strepteccoci growing on M17 plates were predominant. A total of 467 isolates selected for their general status were then subjected to MALDI-TOF MS analysis. Combined analysis of MALDI-TOF MS and 16S rDNA sequencing evidenced Lactobacillus fermentum, Lb. paracasei and Lb. rhamnosus as the dominant lactobacilles with a percentage of 37,9 %, 32,5 % and 14,2 % respectively. Percentage distribution for streptococci was 34 % for Streptecoccus thermophilus, 31,9 for Str. gallolyticus ssp. macedonicus, 14,8 % for Str. lutetiensis/Str. infantarius ssp. infantarius and 12,7 % for Lactoccus lactis. Among enterococci, Enterococcus faecium (41,6 %) and Ent. faecalis (38,5 %) were the most dominant species. In the second part of the study microflora of salty/lesser salty and central/crust part of Mihalic was compared. Lb. paracasei was the mostly isolated lactobacilli species in lesser salty cheese compared to salty ones. Comparison of central and crust part of cheeses revealed that Lb. fermentum count was higher in central part whereas Ent. faecium was dominant in crust part. Collected isolates were stored in ''Dairy Product Gene Bank'' starter culture collection under TSGB3001 code and further studies are necessary to better understand their potential role in cheese manufacturing.