PCR verification of microplate phenotypic system identification for LAB from traditional Western Balkan raw milk cheeses

Fermentation and ripening specificity of traditional cheeses are predominantly directed by the natural microbial community present in milk selected by the cheese-making environment and technology. Therefore the traditional cheeses are unique products with specific microbiota biodiversity. There are several approaches for the identification of microbial population, however all of them have certain advantages and disadvantages. In this study the eligibility and performance of the Biolog phenotypic identification system (Biolog, Inc.) with GEN III microplates was tested. Parallel to this method, polymerase chain reaction with genus- and species-specific primers was performed. One hundred sixty-five isolates from nine types of artisan cheeses were isolated and analysed. Cheeses were produced from raw ewe's milk in Slovenia, Bosnia and Herzegovina, Croatia and Serbia. The Biolog phenotypic identification system identified 90 isolates, but only 55 identifications acquired by the Biolog system were supported by polymerase chain reaction at a genus level and 28 at a species level. The obtained results showed that the reliability of commercial phenotypic identification systems was inadequate when analysing lactic acid bacteria isolates from natural, spontaneous fermentations and needs to be additionally corroborated by genotypic identification methods.