Microbiological evaluation of poultry sausages stored at different temperatures

The aim of our study was to evaluate the microbiological quality of poultry sausages, which were stored at different temperatures (4 °C, 15 °C). Total count of bacteria, coliform bacteria, yeasts and filamentous microscopic fungi were detected in poultry sausages. Microbiological quality was evaluated using the horizontal method for the determination number of microorganisms. Total count of bacteria in sausages stored at 4 °C ranged from 1 × 101 CFU.g-1 in sample 1 (after opening) to 4.35 × 104 CFU.g-1  in sample 1 (7th day of storage). Total count of bacteria in sausages stored at 15 °C ranged from 3.25 × 103 CFU.g-1 in sample 1 (after opening) to 3.12 × 106 CFU.g-1 in sample 1 to 3.12 × 106  CFU.g-1 in sample 1 (7th day of storage).  Coliform bacteria in sausages stored at 4 °C ranged from 1 × 101 CFU.g-1 to 3.15 × 105 CFU.g-1. Coliform bacteria in sausages stored at 15 °C ranged from 1.54 × 103 CFU.g-1 to 1.40 × 106 CFU.g-1.  Yeasts and microscopic filamentous fungi in sausages stored at 4 °C ranged from 2.75 × 104 CFU.g-1 to 1.40 × 106 CFU.g-1.  Yeasts and microscopic filamentous fungi in sausages stored at 15 °C ranged from 1.30 × 104 CFU.g-1 to 1.44 × 106  CFU.g-1. Total count of bacteria, coliform bacteria, yeast and microscopic fungi were not in accordance with Codex Alimentarius of Slovak Republic on 3rd day in samples stored at 15 °C

Oxidative stability of chicken meat after propolis extract application in their diets

In the experiment, the effect of the addition of propolis extract in a feed mixture for chicken broilers Hubbard JV on oxidative stability of breast and thigh muscles during refrigerated storage was investigated. In the experiment were included 90 pieces of one day-old chicks, which were divided into 3 groups (control, E1 and E2). Chickens were fed by ad libitum system until the age of 42 days. These feed mixtures were made without antibiotics preparation and coccidiostats.  Propolis extract in an amount of 150 mg.kg-1 (E1) and 450 mg.kg-1 (E2) was added into feed mixtures for experimental groups. During whole period of refrigerated storage were higher values of MDA determined in control group compare to experimental groups. The higher average MDA value determined in breast muscels of broiler chicken hybrid combination Hubbard JV was in samples of control group (0.157 mg.kg-1) compared to experimental groups E1 (0.140 mg.kg-1) and E2 (0.130 mg.kg-1) after 6-month of refrigerated storage. Significantly higher values of MDA were determined in control group compare to second experimental group from fourth month to the end of storage. The significantly lower value of MDA was determinated in first experimental group compare to control only at 6 month of storage. Trend of thigh muscle oxidation stability of chicken hybrid combination Hubbard JV was during 6 months of refrigerated storage similar than in breast muscle. The higher average MDA value determined in thigh muscels was in samples of control group (0.170 mg.kg-1) compared to experimental groups E1 (0.150 mg.kg-1) and E2 (0.139 mg.kg-1) after 6-month of refrigerated storage. Significantly higher values of MDA were determined in control group compare to second experimental group from fourth month to the end of storage. Higher amount of MDA in thigh muscle compare to breast muscle is due to by higher amount of fat occurred in thigh muscle

Selected parameters of quality and safety of herbal tea

The aim of this work was to assess the heavy metal presence and possible microbiological contamination in herbal teas. Evaluation of selected tea products was performed from Nitra locality during years 2009 - 2013. Microscopic filamentous fungi detection, bacteria such as Escherichia coli and Salmonella spp. were compared to requirements given in the Codex Alimentarius of Slovakia. The highest permissible limit for microscopic filamentous fungi was not exceeded (in 32 observed herbal tea samples). For incidence of Escherichia coli, 93 samples were investigated and for Salmonella spp., 91 herbal tea samples. No sample showed the presence of Salmonella spp., and at E. coli maximum permitted presence was detected below limit. Among chemical parameters, cadmium, lead and mercury content were monitored. The highest amount of lead and mercury was found in year 2012. In 2009, the highest cadmium content was found. The average content of lead in all 100 inspected herbal tea samples was 0.784 mg.kg-1 so all the samples met requirements defined in the legislation. The mean content of mercury (98 investigated herbal tea samples) was 0.0161 mg.kg-1 so all samples met the requirements as well. Average cadmium content was 0.1702 mg.kg-1 while the highest permitted limit for cadmium is 1.0 mg.kg-1. All herbal tea samples were in accordance with the legislation except one (white willow bark tea) with a very high content of cadmium (4.36 mg.kg-1)

Lipid oxidation in chicken meat after application of bee pollen extract, propolis extract and probiotic in their diets

In the experiment, the effect of the addition of bee pollen, propolis extract and probiotic in a feed mixture for chicken broilers Ross 308 on oxidative stability of breast and thigh muscles during chilled storage was investigated. In the experiment were included 180 pieces of one day-old chicks, which were divided into 4 groups (control, E1, E2 and E3). Chickens were fed by ad libitum system until the age of 42 days. These feed mixtures were made without antibiotics preparation and coccidiostats. Bee pollen extract in amount of 400 mg.kg-1 (E1), propolis extract in an amount of 400 mg.kg-1 (E2) was added into feed mixtures and probiotic (Lactobacillus fermentum) (E3) in an amount 3.3 g added daily to the water given the experimental group. During whole period of chilled storage were higher values of MDA determined in control group compare to experimental groups. The higher average MDA value determined in breast muscels of broiler chicken hybrid combination Ross 308 was in samples of control group (0.129 mg.kg-1) compared to experimental groups E1, E3 (0.125 mg.kg-1) and E2 (0.115 mg.kg-1) after 7-day of chilled storage. Significantly higher values of MDA were determined in control group compare to second experimental group on the end of storage. Trend of thigh muscle oxidation stability of chicken hybrid combination Ross 308 was during 7 days of chilled storage similar than in breast muscle. The higher average MDA value determined in thigh muscels was in samples of control group (0.142 mg.kg-1) compared to experimental groups E1 (0.137 mg.kg-1), E2 (0.125 mg.kg-1) and E3 (0.138 mg.kg-1) after 7-day of chilled storage. We have not determined statistically significant differences between testing groups on the end of storage. Higher amount of MDA in thigh muscle compare to breast muscle is due to by higher amount of fat occurred in thigh muscle

Texture quality of muskmelons (Cucumis melo L.) From different retailers during storage

The subject of study was to assess and to compare the effect of storage time on flesh firmness and skin strength in muskmelons (Cucumis melo L.) obtained from supermarket and marketplace. Texture quality of fruit is considered to be the major determinant for customer preference that depends on harvesting maturity and proper storage conditions of fruit and its fresh-cuts. Changes in flesh firmness and skin strength were measured periodically in stored fresh-cut fruits in both groups for initial, 2nd, 5th and 6th day. Analysis of basic physical parameters revealed that muskmelons from marketplace had higher height and width perimeter and therefore also a higher weight, compared to those ones from supermarkets. Textural analysis pointed out to significant differences (p <0.05) in flesh firmness among initial day group and all tested groups from 2nd, 5th and 6th day in muskmelons from supermarket. In marketplace muskmelon group was observed significant difference (p <0.05) between samples from initial day and 5th day. Within the skin strength, there were demonstrated significant differences (p <0.05) between initial day and most of remaining storage days in both supermarket and marketplace muskmelons groups. The data for flesh firmness and skin strength were used in linear regression analysis, in order to evaluate trends during storage period. The correlation coefficients of linear model describing relationship between storage time and skin strength for the group of supermarket and marketplace muskmelons were r = -0.828 and r = -0.780, respectively, which indicated approximately equal relationship between time and skin strength in both tested groups. A strong inverse correlation (r = -0.816) between time and flesh firmness in the group of supermarket muskmelons was noticed. In the group of marketplace muskmelons, there was observed weaker inverse correlation (r = -0.441) within this relation, compared to commercial ones. The model revealed that the muskmelons from marketplace retailers tend to maintain the flesh firmness for a longer time than did commercial ones. The melon flesh quality was markedly changing during storage period and highly depends on the muskmelon origin

The prevalence of Salmonella infections in laying hen flocks producing eggs and their impact on the public health

Since 2008, Slovakia has implemented the National control program of Salmonella infections in laying hen flocks. This program requires the farm operators to monitor and investigate the invasive types of Salmonella (S. Enteritidis and S. Typhimurium) according to STN ISO 6579. The aim of this study was to perform a microbiological examination of dust and chicken droppings samples of laying hens in the Trenčín region for the presence of Salmonella by Horizontal method according to STN ISO 6579: 2002, to compare results with the statistics across Slovakia and selected EU countries and to evaluate the impact of official controls of salmonellosis in animals and humans.  In the years 2009 - 2013 in the Trenčín region, 730 samples of dust from the conveyor belts and droppings of laying hens were taken to determine the prevalence of Salmonella in individual rearings. In these years, the incidence of positive samples was found from 0% to 29.17%. For the period from 2009 till 2013 was reported 22833 salmonellosis cases in human population of Slovakia, while in the Trenčín region it was 2636. Five-year EU-trend (2009 - 2013) showed a statistically significant decrease of salmonellosis occurence (with a mean reduction of 12% per year). The Wilcoxon signed-rank test was performed in order to provide in-depth epidemiological assessment of salmonellosis cases in Trenčin region in relation to selected characters: etiological agens, transmission mechanism, age, location as well as seasonality of infection

Effect of different phytogenic additives on oxidation stability of chicken meat

The aim of the study was to evaluate the oxidative stability (TBARS method) of breast and thigh muscle after application of feed mixtures enriched by phytogenic additives. The experiment started with 150 pieces one-day-old chicks of Cobb 500 hybrid combination. They were divided into one control (C) and two experimental groups (1st EG and 2nd EG). Each group included 50 chicks. In experimental groups, feed additives were applied as followed: 100 mg.kg-1 Agolin Poultry (in the 1st EG) and 500 mg.kg-1 Agolin Tannin Plus (in the 2nd EG). Experimental broiler chickens were fed during 42 days by ad libitum. Chicken meat samples of breast and thigh muscle were analysed in the 1st day, 1st, 2nd, 3rd, 4th, 5th and 6th month of storage in frozen storage at -18 °C. We recorded positive influence on chicken meat oxidative stability in all experimental groups with application of phytogenic feed additives. Obtained results showed that applied phytogenic additives had positive influence on oxidative stability of breast and thigh muscles. At the end of frozen storage (in 6th month), we found higher malondialdehyde (MDA) values and lower oxidative stability (p <0.05) of breast muscle in control group (0.167 mg.kg-1) compared to experimental groups (from 0.150 mg.kg-1 in 1. EG to 0.155 mg.kg-1 in 2. EG). In the thigh muscle, we found similar tendency of oxidative changes as in the breast muscle. At the end of frozen storage (in the 6th month), MDA average values of thigh muscle were higher (p <0.05) in control group (0.181 mg.kg-1) compared to experimental groups (1. EG 0.164 mg.kg-1 and 2. EG 0.169 mg.kg-1). Significant differences (p <0.05) between the control and experimental groups were found from the 5th month of storage in thigh and breast muscle. Obtained results indicate positive influence of phytogenic additives applied in chicken nutrition, namely on stabilization of fatty substance to degradation processes

TEXTURAL CHANGES IN CARROT DURING COOKING

The aim of the study was to evaluate textural changes in carrots during cooking and to find optimal cooking time of carrots. Using a TA.XT Plus Texture Analyser, texture profile analysis (TPA) of carrot hardness, springiness, cohesiveness, gumminess and chewiness after 5, 10, 15 and 20 minutes of cooking was performed. The highest value for hardness was observed in raw carrot (10167.5 g). The lowest value for hardness (1378.92 g) was observed after 20 minutes of thermal processing. Using the Analysis of Covariance (ANCOVA), it was found out how carrot hardness during cooking varies with the other textural parameters from TPA analysis. The coefficient of determination was 0.9955 and it explained 99.55% of total variability for the TPA analysis results. The highest differences in hardness were observed in the first 5 minutes of cooking. The significance of the model was determined by The Fisher´s F test. The probability corresponding to the F value was lower than 0.0001, it would be taking a lower than 0.01% risk in assuming that there was no effect of the explanatory variables. The results implied that the optimal cooking time of carrots lies in range of 10 and 15 minutes

Flavored whey drinks: preparation and evaluation of selected parameters

The aim of our work was the preparation of fermented flavored whey beverages using whey, probiotic cultures and suitable flavors. Whey fermentation by lactic acid bacteria appears to be an interesting alternative to improve the properties of whey and thus to offer its exceptional nutritional value, not only because of whey protein contained, but also due to the valuable products produced by microorganisms. Pasteurized whey was enriched by the addition of sheep culture ZS-25, which was isolated from sheep cheese and contains more varieties of species Lactococcus lactis, and also by the probiotic culture containing the microorganisms of Bifidobacterium sp., Lactobacillus acidophilus, Streptococcus thermophilus. We focused our attention to select the appropriate type and concentration of flavor as well. Sensory evaluation was performed by the committee consisting of five intentionally selected professionally qualified persons. Taste of fermented whey drink was main observed property. Assessment of prepared whey drinks was repeated four times, each group consisted of 5 samples according to the following structure: sample A - whey drink with culture without flavoring, sample B - whey drink with culture and exotic flavor, sample C - whey drink with the culture and flavor of cranberry-grape-strawberry, sample D - whey drink with the culture and peach-orange flavor, sample E - whey drink with the culture and strawberry flavor. Flavored fermented whey beverages were sensorially evaluated. The order of individual samples determined by the evaluators was statistically processed by the Friedman test. Table value for this test for five evaluators and 5 samples is 8.99. The calculated values for all four sensory evaluations we performed, were higher than 8.99, so we rejected the null hypothesis and proved that among the different flavored whey drinks it is statistically significant difference. Overall, the worst evaluated was whey drink without flavoring. As the best accepted was strawberry flavor, it does not matter whether it was used sheep or cow whey, or sheep culture, ZS-25 or probiotic. We can conclude that strawberry flavor is the most appropriate to cover undesirable taste of whey

Natural honeys of different origin as a source of biologically active components

The purpose of this study was to examine the polyphenol and flavonoid content, electrical conductivity and color measurement of 15 natural honeys. Honey samples were collected from different locations of Slovakia (6 samples), Poland (5 samples) and Serbia (4 samples) and were obtained directly from local beekeepers. The mean content of polyphenolic substances ranged from 611.2 to 2962.24 mg.kg-1. Multifloral honeys were shown to be a good source of TPC, they ranged from 611 to 1257.12 mg.kg-1, those of the samples originated from Poland showed 611 to 990 mg.kg-1, and from Slovakia 703.7 to 1257.12 mg.kg-1 TPC.  Forest honeys were found to be also good source of TPC, they ranged from 769 to 1052 mg. kg-1. High correlation was found between TPC and flavonoid content (r=0.92). Mean content of flavonoids in the honeys expressed as rutin content ranged from 112.46 to 846.58 mg.kg-1. Multifloral honeys ranged from 112.49 to 592.35 mg.kg-1, those of the samples originated from Poland proved 112.49 to 189.13 mg.kg-1 flavonoids, and from Slovakia 127.48 to 592.35 mg.kg-1.  Forest honeys as a source of flavonoids were proved to be from 136.48 to 266.79 mg.kg-1. Objective measurement of honey color was performed by the L*a*b* system