Traditional sourdoughs in Bulgaria were almost extinct during the centralized food production system. However, a rapidly developing trend of sourdough revival in the country is setting the demand for increased production and use of commercial starter cultures. The selection of strains for such cultures is based on geographical specificity and beneficial technological properties. In this connection, the aim of this study was to isolate, identify and characterize lactic acid bacteria (LAB) and yeasts from typical Bulgarian sourdoughs for the selection of strains for commercial sourdough starter cultures. Twelve samples of typical Bulgarian sourdoughs were collected from different geographical locations. All samples were analyzed for pH, total titratable acidity and dry matter content. Enumeration of LAB and yeast was also carried out. Molecular identification by 16S rDNA sequence analysis was performed for 167 LAB isolates, and 106 yeast strains were identified by ITS1-5.8S-ITS2 rRNA gene partial sequence analysis. The LAB strains were characterized according to their amylolytic and proteolytic activity and acidification capacity, and 11 strains were selected for further testing of their antimicrobial properties. The strains with the most pronounced antibacterial and antifungal activity are listed as recommended candidates for the development of starter cultures for sourdoughs or other food products.

Food adulteration regarding species origin of meats is a common problem in the meat products sector. With regard to horse meat, its undeclared use in food products is not only a fraud, but could present a health risk since is often associated with the presence of the veterinary drug phenylbutazone in meat products. Therefore, it is important to use reliable methods for authentication of meat products regarding their species composition, which are applicable to complex food matrices. Polymerase chain reaction (PCR) with species-specific primers remains the most widely used analytical approach to detect species-related food adulteration due to its high sensitivity and specificity. The aim of the present study was to establish the authenticity of 20 different meat products on the Bulgarian market without declared horse meat content by using a species-specific PCR method. The specificity test of the PCR method used showed no amplification of DNA from beef and pork. A detection limit of 0.01% horse DNA in three-component meat mixtures was established for the PCR method. The PCR method enabled detection of undeclared presence of horse meat in 25% of the analyzed meat products, which demonstrates the need for strict control regarding authenticity in the meat food chain.