Microbial Diversity of Traditional Livno Cheese from Bosnia and Herzegovina

Abstract

Traditional dairy products, especially cheeses, represent part of the cultural food heritage of many countries. In addition, these cheeses constitute microbiological “reservoirs”, of which many have been lost due to the introduction of the pasteurization of milk in the dairy industry. Increased awareness of the importance of microorganisms that make up the biodiversity of traditional cheeses, as well as the development of molecular methods in recent decades, have enabled efforts to identify and preserve them. Traditional Livno cheese is a full-fat hard cheese, considered one of the most famous traditional cheeses of Bosnia and Herzegovina and is seasonally produced from a mixture of raw sheep’s milk supplemented with cow’s milk. Often, Livno cheese has variable quality, due to microbial contamination and poor milk quality. In this study, traditional Livno cheese was studied during the ripening of cheeses produced by different producers during two seasons. Culture-dependent analyses were made during ripening using microbiological plating on suitable media. Likewise, culture-independent methods Denaturing Gradient Gel Electrophoresis (DGGE) and Automated Ribosomal Intergenic Spacer Analysis (ARISA) were used to elucidate the cheese microbiota. Results of analysis showed Lactococcus spp., Streptococcus spp., Lactobacillus spp., Pediococcus spp. and Leuconostoc spp. to be dominant species in traditional Livno cheese. However, when comparing the use of culture-dependent and culture-independent methods in the evaluation of Livno cheese microbiota, Enterococcus was not detected by culture-independent DGGE methods. The microbial population of both the milk and the environment determines the fermentation processes during cheese production and ripening, and thereby defines the quality of this cheese. The numbers of bacteria in the cheese were shown to be dependent on the manufacturer, the degree of ripening and the production season.

Keywords

• raw-milk Livno cheese
• microbial diversity
• spontaneous fermentation
• ripening