Annual judging of dairy products including sensory evaluation of local cheese-maker' cheeses proved that the quality of Latvian classical cheeses is various. In fact, in last three competitions three different manufacturers gained the first place in category of Krievijas and Holandes types' cheeses. It indicates instability of Latvian cheese quality. Two types of semi-hard cheeses (Krievijas and Holandes) were selected for testing the quality of Latvian semi-hard cheeses in the beginning of 2008. Krievijas type cheese was selected from three different manufacturers, but Holandes type cheese - from five different manufacturers. Sensory properties such as flavour, structure and colour were measured using line scale method. Statistical analysis of obtained data showed differences between such assessed properties as colour (yellowness), texture (firmness), holes, flavour (acidity and bitterness) in Krievijas type cheese, and colour (yellowness), texture (firmness), flavour (saltiness) in Holandes type cheese.

Dairy ecosystems have been developing in thousands of years giving us wonderful collection of different types of cheese varieties. On the other hand, modern technology provokes the loss of variability (Adamberg et al., 2007). The only way to keep biological processes under control is to study physiology of microorganisms, and relationships between them systematically, especially non-starter lactic acid bacteria (NSLAB). The number of non-starter lactic acid bacteria increases during cheese ripening and may constitute a dominant population in the mature cheese. The NSLAB diversity, their metabolism and interactions with starter bacteria have an effect on the ripening process of the cheese. The aim of the present study was to investigate the diversity of Lactobacillus spp. during ripening of Krievijas cheese. The diversity of different profiles varied among the cheese samples matured at different temperatures, and the results indicated a correlation between NSLAB species and aroma development (Miķelsone et al., 2009). A higher metabolism of Lactobacillus curvatus at 12 deg C leads to faster depletion of nutrients and approaching the last two phases of microorganism growth curve. However, in each of the cheeses, the microflora had a tendency to be dominated by one Lactobacillus profile at the end of maturation.

Surveys were made of rural artisan cheese factories located in the region of Olancho, Catacamas, and Juticalpa in Honduras (n=10) and in Esquipulas and Muy-Muy in Nicaragua (n=13). The objective was to analyze the milk market of small rural artisan cheese factories in livestock watersheds of Honduras and Nicaragua to determine if: there is a market for higher milk production how much additional milk can the market absorb in each season of the year there is a market for milk of higher hygienic quality. The main buyer of the milk from small and medium scale farmers in Honduras and Nicaragua is the rural artisan cheese industry, which absorbs almost 80% of the milk produced in both countries. Total milk production during the rainy season is about twice that during the dry season, causing an over-supply and scarcity of milk, respectively. The shortage of fluid milk during the dry season leads to an unsatisfied market. The artisan cheese factories in Honduras and Nicaragua would be willing to buy 76% and 55% more milk during the dry season, but this supply is not available due low milk productivity. This fact suggests that an aggressive program for the promotion of shrub legumes with sugarcane to supplement the herd during the dry season would have more impact that the promotion of grasses or legumes for the rainy season when there is little market for additional milk produced. In addition, rural artisan cheese factories in Honduras and Nicaragua, that consider the milk they collect is of bad quality, would be willing to pay a higher price if the option to collect milk of better hygienic quality exists. In Honduras this price would be about 9% higher during the dry season and 11% higher during the rainy season. In Nicaragua the cheese factories would be willing to pay a milk price which is 17% higher, but only during the rainy season. As a result, large incentives exist in both countries to increase milk production during the dry season and to improve the hygienic quality of milk in the studied areas.

The diversity of non-starter lactic acid bacteria in raw, pasteurised milk and maturated Swiss type cheese was tested. The aim of the present study was to analyse the concentrations and representatives of non-starter lactic acid bacteria in raw milk and to evaluate the changes of their concentrations and representatives during pasteurisation of cheese milk and Swiss-type cheese production. The analysis carried out in the study showed a variation in the microbial composition and quantity of raw milk. The most frequently isolated lactobacilli were found at low level in raw milk (mean 27.5×104 CFU mLE-1) and the most frequently identified species were Lactobacillus brevis and Lactobacillus paracasei. The microflora of raw and pasteurised milk is similar analysing lactic acid bacteria representatives in the samples. Lactobacillus brevis and Lactobacillus paracasei were detected in the same samples in raw milk, pasteurised milk and maturated cheese. Our study showed that lactic acid bacteria concentration was quite low in pasteurised milk (1-12 CFU mLE-1), but they grow rapidly in cheese during ripening reaching 1.1-1.8*106 CFU gE-1. The present study has shown that NSLAB in Swiss-type cheese mainly derive from raw milk, and only a few strains survive the processing conditions and grow during ripening.

In this study we described the diversity of lactic acid bacteria and their representatives in raw and thermally treated milk, focusing on their potential in cheese production influencing cheese quality. The aim of the present study was to analyse the concentrations and representatives of lactic acid bacteria in raw milk and to detect the changes of lactic acid bacteria microflora during thermal treatment of cheese milk at a dairy processing plant. The analysis carried out in the study showed a seasonal variation in the microbial composition and quantity of raw milk. The most frequently isolated lactic acid bacteria: lactococci, lactobacilli, leuconostoc were found at low level in raw milk (mean 9.27×103 CFU mLE-1) and the most frequently identified species were Lactococcus lactis, Lactobacillus brevis and Lactobacillus fermentum. The microflora of raw and pasteurised milk is similar to the analysed lactic acid bacteria representatives in the samples. Interestingly, we found the same species in raw milk and pasteurised milk, for example, Lactobacillus brevis and Lactobacillus fermentum were detected in the same samples in raw milk and pasteurised milk. Our study showed that lactic acid bacteria concentration was quite low in pasteurised milk (0-76 CFU mLE-1), but they grow rapidly in cheese during ripening; therefore the definition of limits of the non–starter lactic acid bacteria colony forming units in milk should be reasonable for selection of appropriate raw milk quality for cheesemaking.