engleski

Structural and functional diversity of microbiota in Istrian cheese: analysis of indigenous Enterococcus community

Istrian ewe’ s cheese is one of the most important Croatian traditional products with a long history of manufacturing. The production of Istrian cheese includes many traditional techniques without selected starter cultures such resulting in a significant variation in cheese quality. However, to standardize the technology procedure and to produce the cheese with more defined composition it is necessary to characterize the indigenous microbial community during the ripening process. In order to collect the preliminary knowledge on indigenous microbiota, the present study aimed at investigating the structural and functional diversity of the cheese microbial community with respect to Enterococcus species. Fresh milk and cheese samples were collected from 6 dairy farms during the ripening on monthly base. Samples were subjected to microbiological analysis. In order to preliminary characterize the microbial communities present in respective samples, the total DNA was isolated by Maxwell 16 System procedure. The DNA was subjected to arbitrarily primed PCR (AP- PCR) fingerprinting assay. Enterococcus species were isolated on selective medium for viable count and 10-15 randomly selected colonies for each sample were Gramm stained. A total of 97 Gramm positive isolates from two farms were further identified by combining RAPD PCR using M13 and 10 mer primers, PCR with genus- and species-specific primers. According to RAPD grouping, representative isolates were further analyzed at genus and species level. All isolates were characterized as Enterococcus whereas RAPD analysis classified them into eight distinct groups. Furthermore, all obtained isolates were identified as E. faecalis or E. faecium such presenting the dominance of two respective species and low interspecies diversity. MPN number of isolates was between 7.3 x 103 and 9.5 x 107 showing the lowest abundance in milk samples. Comparison of the profiles generated by AP-PCR revealed that the profiles were distinct for each sample.

Istrian cheese; microbial community; Enterococcus

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