The contents of soluble solids, acids and their ratio as well as phenol content are important indices for quality evaluating of sour cherry fruits. These parameters are influenced by the cultivar and growing conditions. The trial was carried out at the Latvian State Institute of Fruit-Growing to evaluate the effect of woodchip mulch and drip irrigation on fruit quality of sour cherry cultivars 'Bulatnikovskaya', 'Desertnaya Morozovoi', 'Latvijas Zemais', 'Orlica', 'Shokoladnica', 'Tamaris', and 'Zentenes'. The biochemical composition of the fruits was analyzed in 2009 and 2010. The content of soluble solids was determined with the method of refractometry; the content of total acids by titrating with 0.1N NaOH; the total content of phenols with the method of spectrometry. The content of total soluble solids in sour cherry fruits was decreased by use of woodchip mulch. The content of acids, the ratio of soluble solid content to the acid content and the content of the phenols was not significantly influenced by woodchip mulch and drip irrigation. The cultivar 'Desertnaya Morozovoi' showed the highest soluble solid content in the fruits, the cultivar 'Latvijas Zemais' - the highest acid content, and cultivar 'Tamaris' - the highest phenol content in the fruits.

The changes in the serum immunoglobulins concentration were investigated in newborn heifers from birth to 7 days of age. The mothers of calves were determined serum and colostrum immunoglobulins (Ig) concentration. The research was carried out at the Latvia University of Agriculture (LLU), in dairy farm ''Ligotnes'' of the Research and Study Farm ''Vecauce'', in a loose housing system with 530 cows, of which 430 were milking cows. The cows during the dry period were kept tethered in the farm. Eighteen heifers and their dams (Latvian Brown and Holstein breeds) which calved from 30 November 2010 to 23 January 2011 were used in this study. The calves' serum total immunoglobulin concentration at birth was 9.0 ±1.31 mg dLE-1 (or 0.09 mg mLE-1), and after 24 hours (h) it increased significantly to 4.3 mg dLE-1 (or 0.043 mg mLE-1), p is less than 0.05. The immunoglobulin G (IgG) concentration in calf serum after birth was 6.8 ±1.50 mg dLE-1 (or 0.068 mg mLE-1), and after 1 day and after 7 days it did not change significantly. The average Ig serum concentration in cows was 12.6 ± 1.36 mg dLE-1(or 0.126 mg mLE-1), and Ig concentration in colostrum was 18.5 ± 1.68 mg mLE-1. On average, close correlation (r=0.56) was found between cow blood serum IgM and colostrum IgM. Correlation between cow and calf IgG serum concentration proved to be weak (r=0.49).

Milk production and milk composition are of prime economic importance for farmers. It is well known in dairy management that the balanced feeding and holding technology is an important lever by which milk production and milk composition can be modified. The objectives of this work are to establish relation among milk protein and urea content in different farms. Four farms represent three cow breeds (Holstein Black and White, Latvian Brown, and cross breed XP). Individual cow milk samples (n=8400) were collected monthly from September 2009 to November 2010. Milk samples were analyzed for total protein, casein, fat, lactose, and urea content with instrumental infrared spectroscopy method. The average milk yield in farms was significantly different (from 26.8 to 16.0 kg per control day), and average protein content varied from 3.32 g kgE-1 to 3.62 g kgE-1. The urea content in cow milk was between 21.3 to 42.6 mg 100 mLE-1. The average protein content was higher and significantly (p is less than 0.05) different in first yield level (up to 15 kg) for all farms. Overall, in different farm and milk yield levels correlation between protein and urea was low or very low. In the farm C, average urea content ranged between 30.0 and 60.0 mg 100 mLE-1, which indicated problems in feeding or management in the farm. It was established that milk productivity traits significantly (p is less than 0.05) varied in farms with different dairy cow holding and feeding technologies and milk protein and urea content significantly (p is less than 0.05) varied for cows with different milk yield per day.

The non-spore forming gram-positive bacterium Listeria monocytogenes is a food pathogen bacterium and a causative agent of listeriosis. The aim of the study was to determine the survival limits of L. monocytogenes inoculated in manufactured vacuum-packed cold smoked pork depending on shelf time, supported by water activity (aw) and pH values. Enumeration of L. monocytogenes colony forming units per gram (cfu gE-1) was done according to ISO standard. Water activity (aw) and pH values in pork samples were more or less constant and supported L. monocytogenes growth. The behaviour of L. monocytogenes in cold-smoked sliced pork by shelf time, when environmental factors changed minimally and supported growth, largely depended on the initial contamination level. A lag-phase of bacterial growing process before exponential growth rate of inoculated L. monocytogenes depended on initial cell concentration and had 10 days step level if storage temperature was approximately 5 deg C. A significant Pearson’s correlation (p is less than 0.01) was established between the microbiological test values of L. monocytogenes count changes in sliced and packed cold-smoked pork during storage time of 60 days. The main parameter which maintained negative polynomial growth rate of L. monocytogenes in cold-smoked pork was the decrease of live cell concentration in samples below lg 2.0. The experiments were done at the Faculty of Veterinary Medicine of Latvia University of Agriculture and at a sausage manufacturer’s laboratory.

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.

There is growing interest in products without added sugar; thus, sugar consumption is directly related to diabetes and other illnesses such as obesity. A change in the type of sugar and content may therefore both change the perception of sweetness and texture of products. The aim of the research work was to evaluate properties of agar-agar jellies prepared with inulin syrup, galactose syrup and malt extract to replace sugar. Agar gels were prepared to substitute sugar with inulin syrup, galactose syrup and malt extract. Texture of experimental samples was determined by using a Texture Analyser (Model TA.XT Plus; Stable Micro Systems). Colour of jellies was evaluated by using Colour Tec-PCM and Jenway 3510 was used for pH measurements. Obtained results showed that different kinds of sugar containing syrups could be used as sugar substitute for production of a new type jellies. Hardness of the experimental samples is influenced by the sugar type containing syrup. The hardness is determined in the experimental samples by replacement of sugar by increasing concentration of inulin syrup. Decreasing hardness values are observed by increase of added malt extract (maltose) and galactose syrup concentration in samples. The pH values of experimental samples ranged between 3.11 and 4.45. Higher L* value of experimental samples are with galactose syrup. Lightness “L” changed between 20.92 and 18.11 increasing inulin syrup concentration. The same situation can be observed using malt extract as sugar substitute.

Sherbet with crunchy peanut chips could be classified as milk pomade. It is one of popular sweets in Latvia produced by Joint-stock Company Laima, which is one of the oldest producers of sweets in the Baltic States. Freshly made sherbet is soft and savoury but after several days’ storage at the open air gradually hardens, the product loses eye appeal, taste and becomes unmarketable. This problem limits the shelf life, so sherbet with crunchy peanut chips can be marketed only at the local market. The target of this study was to clarify the situation on the market in Latvia and to examine an issue of Latvian consumers’ awareness of milk pomade sweets – sherbet quality indicators, packaging and its presentation to consumers, as well as the sherbet market expandability. A questionnaire was developed – 800 respondents answered on the 14 questions – how well-recognized the milk pomade sweet – sherbet is, what the main features for this kind of sweets selection by consumers are, which quality indices are important for consumers. One of most important questions was to get know the consumers opinion about sweets, mainly sherbet possible packaging kind and the market turnover. Summarizing the questionnaire data, the response from consumers in Latvia was heartening – they like milk pomade candies. As a primary quality defect the hardness of sherbet was mentioned. Eliminating this main failing of quality, the demand of sherbet on the market could rise, as well the product marketing opportunities will grow.

Rabies is present in the entire territory of Latvia and as a zoonosis poses risk to both human and animal health. The disease is also endemic in countries bordering with Latvia, namely Lithuania, Estonia, Russia and Belarus. Reservoirs for the rabies virus (RABV), the causative agent of the disease in Latvia, are the red fox (Vulpes vulpes) and the raccoon dog (Nyctereutes procyonoides). The first large-scale oral rabies vaccination campaigns using aircrafts were carried out in spring and autumn 2005 using Fuchsoral® SAD B19 oral vaccine baits. In total, 1,894 wild animals (1,366 foxes and 528 raccoon dogs) were hunted in vaccinated areas to evaluate the efficacy of the campaign. After spring and autumn vaccination campaigns, 51.6% of the fox and raccoon dogs were positive for tetracycline. Herd immunity was found in 50.5% of foxes and raccoon dogs using FAVN test and only in 14.8% using ELISA test. After oral vaccination campaigns, rabies incidence decreased in vaccinated area, however, an increase of the incidence was observed in unvaccinated area. Despite the slight increase in rabies incidence in Latvia in 2006 compared to 2005, in 2005 only 141 rabies cases (30%) were found in the vaccinated area whereas 330 cases were detected in the unvaccinated area.

The European Parliament and Council Directive 2003/30/EK ‘On the promotion of the use of biofuels and other renewable fuels for transport’ determines that pure or straight vegetable oil, produced from oil plants by pressing, extracting or comparable procedures, crude or refined but chemically unmodified, compatible with common engines, and corresponding to emission requirements, is also considered as biofuel. The biggest problems imposed by these conditions are directly associated with the carrying-out of the emission requirements, because when using vegetable oil as a fuel, usually increases the composition of the solid particles and nitrogen oxides in exhaust gases, that not only adversely affect the environment, but also is a serious threat to human health, and as a result trying to save the world from the global warming, human health continues to deteriorate. It is therefore necessary to carry out studies and find solutions to reduce harmful emissions from diesel engines when using vegetable oil fuel. For more qualitative and effective research on vegetable oil fuel emissions, the equipment for vegetable oil fuel testing has been developed. This equipment allows fast checking of theoretically proposed hypotheses and detailed calculations for vegetable oil fuel combustion processes and objective data acquisition. The equipment consists of the classic diesel engine adapted for work with vegetable oil and is equipped with several high-precision devices to get and store the measuring data. During pilot tests the optimal measuring modes (engine rotation frequencies, number and duration of repetitions) for further research are estimated.

Computer models of bioprocesses have become an essential tool in biotechnology. This paper describes various bioprocess scaleup releated problems. The problems at different scales are explained. In this paper the use of computer model in E.coli fermentation scale-up from shake flask to laboratory scale bioreactor is discussed. A black box modelling approach was used. Fermentation results have been visualized and discussed. The computer model created in Matlab environment was used for bioprocess behaviour prediction. Possible bioprocess scale-up software improvements and bioprocess optimization are discussed.