Microbiological and chemical quality of fresh and frozen whole trout and trout fillets

The rainbow trout (Oncorhynchus mykiss) is considered as an important fish in the freshwater aquaculture and play a significant role in the human diet. The final quality of fish depends on the chemical and microbiological quality of fish at the time of freezing as well as on other factors including storage temperature and processing. The purpose of the study was to determine the microbiological status of 30 samples cooled and frozen trouts collected from approved farm in the Turiec region, territory of middle Slovakia. Total viable counts (TVCs), psychrotrophic bacteria, Pseudomonas spp. and also total volatile base-nitrogen (TVB-N) and pH were measured in samples of fresh (1. and 7. day of storage at 0 - 2 °C) and frozen whole trout and trout fillets. Frozen samples were stored at -18 °C during 1, 3, and 6 months. Samples were collected from the skin, muscles (sterile) and muscles after filleting. The microbiological quality of samples varied between fresh and frozen (6th month of storage) regarding TVCs and also between samples taken from the skin and muscles after filleting compared to muscle samples collected sterile regarding all tested bacteria. A large number of bacteria (pathogens and spoilage bacteria) enter with the raw material and in particular the skin contamination had a negative impact on the increase of microbial load in fillets. All processing techniques and procedures including filleting therefore must be designed and aimed to minimise contamination and growth of microorganisms in fish. However, based on the results of TVB-N analysis, differences between fresh and frozen samples were found, but all the samples were suitable for human consumption

Polyphenolic content and antioxidative activity of wines from the Sobrance wine region

The purpose of this study was to compare the content of total polyphenols and antioxidant properties of wines from the Sobrance wine region. White wines generally showed lower content of polyphenols and also posses lower scavenging capacity against DPPH radical than red wines. However, when we compared antioxidant properties of wines to protect polyunsaturated fatty acids against oxidation using to TBA method, no differences were detected. The antioxidative capacity of white wines was comparable to red wines and was higher than antioxidant capacity of ascorbic acid solution (0.2 %). The best antioxidant properties were recorded in Cabernet sauvignon (2010) and Frankovka modra (2009) wines

Oxidative stability of chilled chicken meat after feeding of selected plants

The effect of feeding of lemon balm (Melissa officinalis, L) and combination of yarrow (Achillea millefolium L) and hawthorn (Crataegus oxyacantha L) on oxidative stability and sensory properties of produced poultry meat was investigated. Sixty one-day-old commercial broiler chicks (ROSS 308) were used in our experiment, divided into 3 groups, and fed 41 days, as follows: control (K) was fed with standard diet without supplementation of plants; second group (M) was fed with standard diet supplemented with grounded lemon balm in concentration 2 % per 1 kg; and third group was fed with standard diet supplemented with grounded yarrow (2 %) and hawthorn (1 %). Results showed that supplementation with lemon balm, and mainly combination of yarrow and hawthorn in the diet significantly caused reduction of lipid oxidation processes in thigh meat during chilling storage of samples. In addition, supplementation of plants in the diet had positive effect on sensory quality of meat of broiler chickens.

Verification for the presence of inhibitory substances in poultry meat after the consumption of the feed mixture supplemented with fermented feed

The European Union has an obligation to ensure that feed produced in the European Union is safe for animals and also humans by ensuring food of animal origin is safe and wholesome. An increasing demand for safe, wholesome and nutritious animal products has led to the search for alternative substances in animal feed. Fermented feed has gained a lot of popularity in many animal diets today. They meet the demand for animal nutrition due to the formation of target substances with the desired properties. As some of them are attracting attention as potential antimicrobial agents that inhibit the growth of certain microorganisms, and the products of animal origin are controlled for the presence of residues of inhibitory (antimicrobial) substances, the aim of this work was to verify the presence of inhibitory substances in poultry meat (muscle, heart, liver, kidneys of broiler chickens) after the consumption of the feed mixture with addition of fermented feed (wheat bran fermented with the strain Umbelopsis isabellina CCF 2412) in a dose of 10 % of the total amount of the feed. The detection of residues was performed by two approved microbiological screening methods, the screening test for the detection of antibiotic residues (STAR) and the Premi®Test. Both methods detected the positive results and pre-identified the presence of residues of the inhibitory substances not only in the meat of broiler chickens but also in the investigated fermented feed. Due to the antimicrobial potential of the fermented feed and the possible presence of the false-positive results, each positive result must be confirmed by a confirmatory analysis

Effect of feeding of prefermented bioproduct containing gamma-linolenic acid and beta-carotene on selected parameters of broiler chicken meat quality

The aim of the work was to evaluate the effect of addition of prefermented bioproduct with a increased content of polyunsaturated fatty acids (especially gamma-linolenic acid) and beta-carotene into commercial feed on the selected qualitative parameters. The chemical composition, the color, the loss of water, the pH and the concentration of lactic acid of the meat of broiler chickens (COBB 500) were monitored. Bioproduct was prepared from corn scrap, which was fermented using the lower filamentous fungus Umbelopsis isabellina CCF2412. The prepared material was mixed into the commercial compound feed intended for broiler chickens at a ratio of 10%, and was fed from the 11th day of age of the chickens until the time of slaughter. The obtained results were compared with the results of control group, which was represented by broiler chickens fed only with a commercial compound feed. Feeding of bioproduct, in terms of chemical composition, affected mainly the fat content in breast and thigh meat, which was lower in the experimental group. Meat color (measured by colorimetric assay) was not affected and differences were significant only at a value a*, which was higher in the experimental group. Statistically significant differences in the water losses of meat were not recorded, but the feeding of bioproduct affected the pH of the meat, and also the concentration of lactic acid and both parameters were higher in the meat of control group