The objective of the research was the shelf life extension of a salad with meat in mayonnaise. The microbial stability of the salad with meat in mayonnaise packaged under vacuum, in modified atmosphere, and using 'Sous vide' technology was examined and compared with conventionally packaged (in ambient air) salad. The salads were packaged in polyamide/polyethylene pouches with barrier properties as well as in pouches made from biodegradable plasticized poly-β-hydroxybutyrate or polylactic acid film. Control samples without preservatives were packed in traditional polypropylene containers covered with non-hermetic lids. PURASA L Powder Opti Form (sodium lactate) in the amount 5 g kgE-1, 10 g kgE-1, and 15 g kgE-1, and ethyl alcohol in the amount of 2 ml were used as single preservatives for separate samples. The studies of the samples were carried out after 1, 3, 7, 10, 15, 18, 25, 29, 42, and 52 storage days at the temperature of +4+-0.5 deg C. Experimentally the quality of the salad with meat in mayonnaise was characterized by measuring the total plate count of microorganisms. The obtained results indicate that different packaging technologies and addition of preservatives show significantly different influence on the microbial growth in different samples. 'Sous vide' packaging technology was effective for the shelf life extending and guarantee of safety of the salads with meat in mayonnaise.

The most non-starter lactic acid bacteria (NSLAB) isolated from semi-hard cheeses are heterofermentative and handled as one of the reasons of cheese off-flavours and yield defect but at the same time majority of researches argued positive effect of NSLAB on cheese flavour formation and diversification due to rendered compounds of chemical reactions. The amount of NSLAB in cheese varies from 10 at the beginning of ripening to 105 cfu mlE-1 within 6-8 weeks. The aims of this paper were to establish diversity of NSLAB in commercial samples of Krievijas and Holandes cheeses, and to evaluate the effect of ripening temperatures on NSLAB in the trials of Krievijas cheese. A total of 12 commercial cheese samples from seven different Latvian manufacturers and trials from one cheese manufacturer were examined. The trials were ripened for 60 days at different temperatures - 6 deg C and 12 deg C. Serial dilutions of each cheese sample (1:1000 and 1:10 000) in saline were made. NSLAB were cultivated using MRS media. Strain identification was performed by the API 50 CHL system (BioMerieux, Marey l'Etoile, France). In commercial samples of Krievijas cheese dominance of L. curvatus was observed, simultaneously L.plantarum and L.paracasei subsp. paracasei were isolated. Whereas in Holandes cheese samples dominance of L.paracasei subsp. paracasei was noted and L.plantarum, L.curvatus, L.rhamnosus and L.acidophilus were isolated. In the trials ripened at different temperatures prevalence of L.curvatus was noted. Concentration of Lactobacillus spp. varied from 104 cfu mlE-1 on the first day of ripening and reached the highest concentration (106 cfu mlE-1) after 6 weeks of ripening.

Understanding the efficacy of organic trace minerals has been increasingly important over the past few years as a result of increased customer awareness of their benefits and the increase in the number of commercial products available to the customer. Organically bound trace minerals of interest in animal nutrition specifically include iron, zinc, manganese, copper, cobalt, and selenium. These elements have been shown to improve reproductive efficiency as measured by conception rate, alleviated calving, and reduced placenta expulsion rate. Additional benefits include improved growth performance of calves. The field trials in the period of 2005 – 2007 with Charolais breed beef cattle cows and calves verified efficacy of the premix PROTRACE G containing Fe, Zn, Cu, Mn, and Co chelates, Se-amino acid (selenomethionine), potassium iodide, and vitamins A, D3 and E. Average calving rate of experimental group cows fed diet with added premix was 20 – 30 min, placenta expulsion time - 28 – 31 min, but in control group fed only basal diet - 2 h 21 min and 1 h 30 min – 2 h 09 min (p is less than 0.05) respectively. Live weight gain of calves and heifers of the experimental group was on 35 – 39% higher (p is less than 0.05) than that in the control group.

This paper discusses the usability of non-parametric knn (k-nearest neighbour) method to detect changes in forest areas from satellite images. Spot Xi images acquired 1999, main forest characteristics from field measured sample plots and data of conventional stand-wise forest inventory from the year 1988 were used to estimate the grids of following forest characteristics: mean age of main forest storey, diameter, basal area, height, volume per 1 ha, as well as the percentages of coniferous, soft and hard deciduous tree species. The differences of grids, created using stand-wise forest attributes from the 1988 inventory and estimated using the k-nearest neighbour methods were experimented to detect changes in the forest. 68.7-75.5% of areas, classified as the potential felling areas, were detected to be clear cut areas or young stands less than 15 years according to the data of stand-wise inventory of year 2003. Different settings for the methods investigated are evaluated, too.

Progeny testing of Scots pine in Latvia is carried out in only few locations, however, material from selections via seed orchards is deployed in various climatic and soil conditions, therefore concerns arise for influence of genotype environment interaction on levels of genetic gain. Problem is addressed based on 3 open pollinated progeny tests, consisting of 80 open pollinated families, located in 3 distant climatic regions in Latvia. Test age is 27 years, therefore not only growth, but also branch quality traits can be reliably analyzed. Strong genetic correlation (rb=0.80-0.94) among sites for tree height and diameter was found, but considerably weaker for branch traits like diameter of thickest branch (rb=0.52-0.67), average branch diameter, and sum of branch diameters (rb=0.41-0.49). Coefficients of additive genetic variation and coefficients of phenotypic variation among family means, determining potential of improvement via breeding, can be inflated by up to half, based on single site estimates for growth traits and double for quality traits. Backward selection based on results of several trials, in contrast to forward selection or utilization of single experiment results, could lead to improvement of branch traits close to the same as for growth traits (height and diameter). Single site narrow-sense heritability estimates for analyzed growth and quality traits are up to twice as large as across site estimates, indicating possibilities of serious bias in genetic gain estimates based on results from one test site. Testing at 4-5 sites for further breeding work is recommended.

The lily (Lilium L.), a vegetative propagated perennial crop, is one of the economically most important flower bulb plants. It is cultivated worldwide as a cut flower, garden plant and pot plant. Lilies, 'the aristocrats of the garden', are very popular for their elegant flowers and stately habit, and offer the gardener an enormous range of colours, forms, and fragrances. The aim of this research was to evaluate the parent plants with the hybrids according to their morphological characteristics: plant height, flower diameter and inflorescence: number of flowers. In a trial, fourteen cross combinations were analyzed in 2006 – 2007. The evaluation was conducted in a lily breeding and growing farm 'Puķulejas', located in Saulkrasti, region of Riga, Latvia. The results showed that, if there were no significant differences in plant height between the parent plants, the hybrids were shorter than their parents. Male parents with short stems produced hybrids with shorter stems. Parental selections of medium and large number of flowers produced hybrids with comparatively large numbers of flowers on a stem, but if parents of different number of flowers were selected, in hybrids the smaller count dominated or prevailed.

Pollution of atmosphere and decrease of fossil fuels stimulates people to search for an alternative energy sources for production of energy, both electrical and heat. In Latvia it is possible to use almost all alternative energy sources for production of energy, including solar energy that becomes more relevant year by year. Solar radiation in direct way makes no hazardous, but, as the intensity of solar radiation in geographical location of Latvia is comparatively low, the utilization of it demands relatively expensive equipment. Production of energy from other sources of energy also demands certain investments as well as the purchase of fuel, maintenance of equipment and presence of different manipulators. In practice several types of solar collector constructions with efficiency from 30 up to 75% exist and expenses vary in the wide range. The average number of sunshine hours in Latvia is about 1800 hours yearly. Nevertheless solar collectors for water heating in Latvia are used. Mostly flat-plate collectors are used whose efficiency often is not sufficient and water has to be additionally warmed-up. The aim of our investigation is to study operation of evacuated tube collector in conditions characteristic to Latvia. It is stated that it is feasible to use evacuated tube collector for water heating in Latvia, especially from March till October. During winter period solar collector can be used as additional energy source for water heating.

This paper presents results of pressure oscillation investigation in hydraulic hitch-system of a tractor Claas Ares ATX 557 during the motion during artificial roughness road test. During experiments oscillation at different driving speed, tyre pressure and hitch-system oscillation damping (turned on/off) were investigated. Tractor hydraulic hitch-system was equipped with a pressure sensor Wika Transmitter ECO-1 and data processing software PicoLog. Results of experiments present maximum pressure peak of 210 bar in the tractor hydraulic system when hydraulic hitch-system oscillation damping system at driving speed 8 km·hE-1 is not used and system pressure peak reduces to value of 180 bar if the hydraulic hitch-system oscillation damping is used.

Large proportion of 30-50 years old spruce stands originated from overstocked plantations can be characterized by low growth potential and present serious problem to forest managers. Although according to legislation unproductive spruce stands can now be clearcut, possible alternative solution allowing a forest owner to remove only trees with the worst growth potential would be also welcome. To be able to recommend any silvicultural measures, information on the inner structural development of the stands is necessary. The aim of this study was to analyze temporal structure of several spruce stands that have originated from overstocked plantations and now belong to the 2nd (increased risk stands) or 3rd (unpromising stands) growth potential groups. Data for the study from seven sample plots located in Forest Research Station ''Kalsnava'' and thinned with different intensity were used. Tree diameter distribution, volume accumulation patterns and tree mortality were analyzed. Correlation between tree diameter and tree diameter difference in the observation period from 2000 to 2006 was weaker than in the observation period from 2006 to 2009, indicating further decline of growth potential. In most cases the major part of the volume was accumulated in the middle of the diameter class distribution. For most of the trees one or both sawlogs were of good or average quality. In order to develop optimal and profitable stand management model, the effect of different thinning methods in spruce stands of low growth potential should be studied in the future.

Prolonged summer drought periods are forecasted for the Baltic Sea region during the 21st century, thus increasing the risk of drought stress of saplings used in forest regeneration. Nevertheless, the vitality of young stands might be increased by the selection of suitable planting material. The aim of this study was to estimate the effect of changes in distribution of summer precipitation on height increment, biomass distribution and root morphology of Scots pine and silver birch planting material commonly used in the forest regeneration in Latvia. Containerized pine and bare rooted birch saplings, planted in three different soil types, were subjected to altered distribution of summer precipitation, provided by the use of automated shelter. Sheltered saplings were weekly irrigated with the sum of precipitation of a corresponding period, while afield planted saplings had an unchanged precipitation regime and served as control. Height increment was measured once per week and estimation of morphology of saplings was done after the end of every vegetation season. Significant (p is less than 0.05) differences in height increment, and shoot and root biomass were observed among the same planting material in different irrigation regimes and soil types. In the control plots of peat soil, pine had a significantly (p is less than 0.05) larger height increment while birch-significantly (p is less than 0.05) smaller compared to experiment. Forecasted longer drought periods might reduce the growth of Scots pine in fertile forest types but silver birch growth might be affected in fertile mineral soils in future.