The research focuses on the study of physically-chemical and microbiological parameter changes in Latvian wild cranberries during convective drying. The research was accomplished on fresh Latvian wild cranberries. The following quality parameters were controlled during the experiments: moisture content (oven-dry method), content of vitamin C (LVS EN 14130:2003), content of polyphenol (HPLC), preparation of samples for microbiological testing (LVS EN ISO 7218:2007), enumeration of yeasts and moulds (ISO 21527-2:2008(E)), counting of lactic acid bacteria (LVS ISO 13721:1995), and total plate count (LVS EN ISO 4833:2003A). The research detected the following optimal convective drying parameters of wild cranberries: temperature – +50±1 deg C and drying time – 20.3 hours. The moisture content of dried berries equalled to 9.0±0.1%. The content of vitamin C decreased 1.9 times in wild cranberries dried at the temperature of +50±1 deg C compared with the content of vitamin C in non-dried cranberries and was 13.05 mg 100 gE-1 in dry matter. The results of current experiments show, that the content of such polyphenols as gallic, caffeic, and epicatechin acids decreased 9.70, 9.90, and 11.68 times, respectively, during the treatment at temperatures up to +50±1 deg C compared with the initial content of these compounds in non-dried berries. The drying temperature substantially influences the microflora development in cranberries. It is possible to decrease significantly the content of LAB, mould, and fungi in berries provided the drying temperature of the wild cranberries does not exceed +50±1 deg C, thus prolonging the ready product shelf-life.

Kvass is a non-alcoholic beverage produced by fermenting kvass mash with yeast; alcohol content in kvass must be less than 1.2% alcohol by volume. Microbiological safety of kvass is an important issue because European Regulation No 2073/2005 on microbiological criteria for foodstuffs does not provide microbiological criteria for kvass production. Microbiological safety of kvass depends on raw materials, personal hygiene, environment, kvass blending and filtration. Experiments were carried out at the Latvia University of Agriculture Department of Food Technology from November 2013 to January 2014. The aim of this work was to assess the microbiological environment changes during kvass production process and shelf-life. Understanding the development of dynamic of microbiological environment provides a better management for kvass production processes. Samples of bread kvass were analysed during production (12 and 13 h) and storage (36, 60, 84, 132, 136 h) at 3 ± 1 °C to determine kvass quality. Yeasts (LVS EN ISO 21527 - 2: 2008), lactic acid bacteria (ISO 9332:2003) and total plate count (LVS EN ISO 4833:2003) were determined in kvass samples. Microorganisms in kvass were identified using API identification system; the dominating microflora in kvass was Saccharomyces cerevisiae and Leuconostoc mesentericus. Changes of total plate count during fermentation and maturation were not significant (p is greater than 0.05).

The present study was undertaken to estimate enzymatically hydrolysed and non–hydrolysed wheat (Triticum aestivum) and rye (Secale cereale) bran microflora. Enzymatic hydrolysis was accomplished by α – amylase from Bacillus amyloliquefaciens and by Viscozyme L which contain a wide range of enzymes responsible for the breakdown of carbohydrates into simple sugars. Wheat and rye bran samples were collected from native mills, namely Stock Company (SC) ‘Rigas dzirnavnieks’ wheat bran with large particle size (WLSR), SC ‘Jelgavas dzirnavas’ rye bran with small particle size (RSSJ), SC ‘Dobeles dzirnavnieks’ wheat bran with small particle size (WSSD) and wheat bran with large particle size (WLSD). Gained results indicate that before enzymatic hydrolysis all of the bran samples showed similar microbiological contamination with total plate count (TPC), yeasts and lactic acid bacteria. Enzymatic hydrolysis of bran gives the possibility to partially eliminate the microbiological contamination with TPC, yeasts and lactic acid bacteria. The amount of microorganisms after enzymatic hydrolysis (before storage) were decreased and ranged from 5.26 ± 0.04 to 5.45 ± 0.01 log CFU gE-1, from 4.81 ± 0.01 to 5.60 ± 0.05 log CFU gE-1, and from 4.09 ± 0.01 to 5.10 ± 0.05 log CFU gE-1, respectively. After eight weeks of storage (temperature – 20 ± 1 °C, relative humidity – 40 ± 1%) enumeration of microorganisms showed significant decrease of colony–forming units in all bran samples. The amount of TPC, yeasts and lactic acid bacteria in the control bran samples fluctuated in a range from 4.84 ± 0.04 to 5.49 ± 0.05 log CFU gE-1, from 4.86 ± 0.03 to 5.25 ± 0.03 log CFU g-1, 3.53 ± 0.03 to 4.21 ± 0.02 log CFU gE-1 respectively.

The objective of the present study was to investigate the microbiological content of cows’ milk in Latvia’s organic farms with a purpose to detect potential microbiological threats in milk. Samples were collected in December 2011 at 12 biological dairy farms of Latvia. Raw milk samples (N=155) obtained from cow composite milk were studied. The total mesophilic aerobic and facultative anaerobic microorganisms (MAFAM), the presence of coliforms and coagulase-positive staphylococci, count of yeasts and moulds were analysed using standard methods. Of the sampled cows 50% had a low somatic cell count (SCC) (LESS THAN 200,000 cells mLE-1), 23% - high, but 27% had a very high SCC (greater than 500,000 cells mLE-1). The mean value of MAFAM in the samples with low, high and very high SCC was 4.7, 5.0 and 5.0 log10 colony forming units (cfu) mLE-1, respectively. The yeasts were present in 57% of milk samples with the mean concentration of 3.1 log10 cfu mLE-1. Moulds were found in 27% of all milk samples; their mean concentration was 4.4 log10 cfu mLE-1. Identified mould strains belonged to genera Absidia, Aspergillus, Geotrichum, Mucor and Penicillium. In cases of subclinical mastitis and latent mammary infection the most distributed mastitis pathogens were Staphylococcus aureus, Micrococcus kristinae, Bacillus cereus and coagulase negative staphylococci.

Aroma forming volatiles are important components of fermented beverages. The aim of current research is to evaluate the influence of different yeast strains on the volatile compounds of fermented apple juice of the variety ‘Lietuvas Pepins’. Apples were harvested in the Latvia State Institute of Fruit Growing. Apple variety ‘Lietuvas Pepins’ juice was fermented with four different commercial yeast strains - Saccharomyces bayanis yeasts ‘EC-1118’, ‘Cider yeast’, Saccharomyces cerevisiae yeasts ‘71B-1122’ and ‘K1V- 1116’. Fermentation was performed in laboratories of Latvia University of Agriculture, Faculty of Food Technology. Volatile aroma compounds of apple juice, yeasts and fermented juice were determined. Extraction of aroma compounds was performed using solid phase microextraction (DVB/Car/PDMS fibre). Analysis of volatile aroma compounds was made using a Perkin Elmer Clarus 500 GC/ MS. The data obtained in the present study shows the influence of the yeast strain on the final chemical and volatile composition. The main group of volatiles in juice was esters, whereas in fermented juices – alcohols. The highest percentage of esters was determined in juice fermented with ‘Cider yeast’ whereas the highest percentages of alcohols – in juice fermented with yeast K1V-1116 and also free terpenes, associated with the floral note. The 71B-1122 strain produced the highest amount of identified volatile compounds. The strains potentially producing a higher number of volatile compounds could contribute to a more complex aroma of the final product, due to their potential ability to utilize and transform numerous apple must precursors.

A total of 120 food samples from 6 traditional and 3 non-traditional (Oriental) public catering establishments in Latvia were taken. Preliminary all food samples were divided in three food groups (categories) depending on the components of the products and processing methods. Ready-to-eat foods (RTE) with high level of total amount of microorganisms (aerobic colony count-ACC) and total coliforms (TC), as well as appropriate infringements of hygienic requirements in public catering establishments which had an impact on microbial contamination were clarified. The reasons for microbiological contamination of RTE and the growth of the microorganisms were analyzed in dependence on food category group, the activity of hydrogen ions (pH) in food, food temperature at the sampling point, their processing mode and composition. Different indicator microorganisms including Staphylococcus, Enterobacter, Escherichia, Bacillus, yeasts, moulds and etc. were identified. The comparison between the temperature and pH and the level of microbiological contamination of the samples of food and hygienic practice in the catering establishments were clarified.

The effect of some ingredients on stability of butter during its storage time has been investigated in order to better evaluate the functionality of confectionery. The research established that butter does not contain enough free fatty acids, derived as a result of hydrolysis, to decrease the number of mould and group of Enterobacteriaceae, but they hinder the growth of yeast and aerobic mesophilic and facultative anaerobic microorganisms. The quality of the products can be provided and propagation of microorganisms can be hindered by the comounds that are not traditional preservatives, such as vanilin and glucose syrop. A 10% glucose syrup additive worked as the facilitator of the development of microorganisms because it increased growth of aerobic mesophilic and facultative anaerobic microorganisms, 50% of glucose syrup additive worked as the procrastinator of the development of microorganisms.