Milan Ž. Baltić

The effects of lairage time and handling procedure prior to slaughter on stress and meat quality parameters in pigs

Lairage time (short - 8min to 2.7h, n=28 vs. long - 14 to 21.5h, n=72) and pig handling (gentle - no use of stick or electric prod, pig not slipping, falling, nor emitting high-pitched vocalizations vs. rough - where any of these occurred) effects on pig stress and meat quality were measured. Blood lactate and cortisol, plus post-mortem pH (pH60min; pH24h), temperature (T60min), drip loss, sensory and instrumental color and meat quality for the longissimus dorsi, pars lumbalis derived meat were determined. Carcass rigor mortis and skin damages were measured. Lairage time significantly affected blood lactate, carcass rigor mortis, skin damages, drip loss, color and meat quality. Handling procedure influenced blood lactate, pH60min and T60min. Long lairage was more stressful, and was detrimental to carcass quality, but caused better meat quality compared to short lairage. Rough handling was related to higher lactate and lower meat quality.

Effects of dietary selenium-yeast concentrations on growth performance and carcass composition of ducks

The aim of the present study was to assess effects of selenium (Se)-yeast diet supplementation on performance and carcass composition in ducks. The study was performed on 240 1-day old ducklings of the same origin (Cherry Valley hybrid), during a 49-day period, which were fed diets supplemented with the following four different levels of Se yeast (ALKOSEL® R397): groups with Se at 0 mg/kg of the diet as-fed, 0.2 mg/kg, 0.4 mg/kg and 0.6 mg/kg. Growth performance (bodyweight, daily weight gain, daily feed intake, feed-conversion ratio) and carcass characteristics (hot and cold carcass weight, chilling losses, dressing percentage, carcass cut yields, and percentage of tissues in breast and thighs with drumsticks) of the ducks were determined. Animals fed high-Se diets (0.4 mg/kg) had higher (P < 0.05) final bodyweight and daily weight gain (from 15 to 49 days) compared with those fed diets with inadequate (0 mg/kg) or with supranutritional (0.6 mg/kg) Se levels. Ducks fed only with basal diet showed a higher (P < 0.05) feed-conversion ratio (from 15 to 49 days) compared with those supplemented with Se at 0.4 mg/kg and 0.6 mg/kg. Dressing percentage was higher (P < 0.01) in the control group (69.50%) than in the group with Se added at 0.6 mg/kg (66.85%). The weights of basic cuts from the duck carcasses did not significantly differ among compared groups. Moreover, the percentage of skin with subcutaneous fat in breast and thighs with drumsticks increased in Se-supplemented groups compared with the control group, while the opposite was determined with the percentage of muscle. It was concluded that a diet containing 0.4 mg of added Se per kilogram produced the greatest growth-performance results in ducks.

Physicochemical parameters and microbiological status of honey produced in an urban environment in Serbia

Honey is a natural substance produced by honey bees (the genus Apis) enjoyed by people due to its unique nutritional and medicinal properties. The aim of this study was to determine the physicochemical parameters (moisture, ash, water-insoluble content, reducing sugars, sucrose, free acidity, diastase activity, hydroxymethylfurfural, and electrical conductivity) and microbiological status (total number of aerobic mesophilic bacteria, total number of sulfite-reducing clostridia, the presence of Salmonella spp., total numbers of fungi and yeasts and the presence of Clostridium botulinum) in honey (honeydew, blossom, sunflower, acacia, and linden) produced in an urban environment in Serbia. We analyzed 19 apiary samples of honey, collected during the 2011 harvesting season, by using recommendation methods. Physicochemical parameters of the examined honey produced in the urban environment indicated the honeys were of acceptable quality. Bacillus spp. were detected in four honeys, yeasts were detected in three honeys, and Clostridium botulinum type E was detected in one honey using PCR. The current study also showed the presence of diverse honey varieties in Serbia.

Seasonal distributions of heavy metal concentrations in different snail (Helix pomatia) tissues from an urban environment in Serbia

The aim of this study was to evaluate the differences between concentrations of heavy metals (cadmium, copper, zinc, iron, and manganese) in terrestrial gastropods, Helix pomatia, collected in four different environment locations in Pančevo city, Serbia. Metal concentrations in the foot and in the digestive gland were measured. Heavy metals cadmium, copper, zinc, iron, and manganese were measured in triplicate by atomic absorption spectrophotometry. Also, this study investigated correlations between the trace element content in the soft tissues and different seasons (summer and fall). The results showed that heavy metal concentrations of the measured elements in both snail tissues were significantly higher in polluted sites when compared to the background levels in the city. In digestive gland tissues, the concentration of heavy metals was higher compared with that in foot tissues. The bioaccumulation (heavy metal concentrations in soft tissues) of heavy metals (Cd, Cu, Zn, Fe, and Mn) in snails, Helix pomatia, has been assessed and related to seasons and sites. Heavy metal accumulation in the soft tissues of snails could provide a powerful monitoring tool for the assessment of environmental heavy metal pollution.

Survival of Salmonella spp. in minced meat packaged under vacuum and modified atmosphere

The effect of different modified atmosphere packaging regimes on the behavior of Salmonella spp. on minced meat was studied. Minced meat was experimentally contaminated with a Salmonella spp. cocktail (S. Enteritidis, S. Typhimurium, S. Infantis and S. Arizonae), packaged under vacuum or modified atmosphere with initial headspaces containing 20%O2/50%CO2/30%N2 and 20%O2/30%CO2/50%N2) and stored at 3 ± 1 °C for 12 days. Samples were analyzed for Salmonella spp., viable and lactic acid bacteria count every third day. Salmonella spp. counts decreased during storage in all packaging types, with reductions of about 1.5 log CFU/g. A significant difference (p < 0.01) was noted between Salmonella spp. counts in meat packaged in vacuum and modified atmospheres, although there was no significant difference in Salmonella spp. count between meat packaged in 50%CO2, and meat packaged in 30%CO2. At the end of the study, there were significant differences (p < 0.01; p < 0.05) in total viable and lactic acid bacterial counts between meat packaged in vacuum and modified atmosphere, and the lowest counts were noted in meat packaged in modified atmosphere with 50%CO2.

The relationship between the carcass characteristics and meat composition of young Simmental beef cattle

The objective was to study the relationships between the carcass characteristics and meat composition of young Simmental beef, classified with regard to conformation and degree of fatness scores, and total lipid content, depending on gender. For this purpose, 90 animals (60 male and 30 female Simmental beef cattle) were analysed. The results of the study showed that gender affected carcass measurement scores and chemical composition of meat through its important effect on overall animal fatness. Referring to correlations, male carcass conformation score was negatively related to slaughter weight, total lipid content and fatness score. On the other hand, slaughter weight, hot and cold carcass weight, dressing percentage and carcass conformation was positively related to fatness score, all of them being significant. However, female carcass conformation score was positively related to slaughter weight, total lipid content and fatness score. Hot and cold carcass weights of female Simmental beef cattle were positively correlated to slaughter weight, total lipid content and carcass conformation score. Carcass conformation score and fatness score were affected by gender of young Simmental beef cattle.

Effect of starter cultures on survival of Listeria monocytogenes in Čajna sausage

The aim of the study was to evaluate the survival of Listeria monocytogenes during the production of Cajna sausage with short maturation time. Sausage batter was inoculated with three different serotypes 4b and serotype 1/2a of L. monocytogenes. Control sausages were without any starter culture added; the second batch was inoculated with strains of Lactobacillus sakei, Staphylococcus carnosus and Staphylococcus xylosus, and the third batch was inoculated with strains of Debaryomyces hansenii, Lactobacillus sakei, Pediococcus acidilactici, Pediococcus pentosaceus, Staphylococcus carnosus and Staphylococcus xylosus. After 18 days of ripening, L. monocytogenes was not detected in any of the sausages, but during this fermentation and drying, the numbers of this pathogen was lower in the sausages inoculated with starter cultures.

Analysis of poultry meat production volume in Serbia from 1984 to 2009.

Poultry meat production has doubled in past 40 years in the world, with the tendency of constant growth, and its production volume exceeds beef, but is behind pork production. For poultry meat production it is typical that its annual increase exceeds pork as well as beef production. The biggest producers of poultry meat are Asia, North and South America and Europe. The most significant category of poultry is meat of young chicken (broilers). Cobb, Ross and Hubbard broiler provenance are most common in Serbia. The objective of this investigation was to analyse poultry meat production volume in Serbia, observed during three six-years periods - A (1984-1989), B (1994-1999) i C (2004-2009). For data processing there were used the data obtained from Statistical Yearbooks of Serbia from 1984. to 2009. It was found out that average poultry meat production in period A was 108,33 ± 7,00 thousand tonnes, than it statistically significantly decreased and in period B it was 76,67±5,54 thousand tonnes, and finally in period C it was 72,17± 5,78 thousand tonnes. [Projekat Ministarstva nauke Republike Srbije, br. TR 31034]

Assessment of welfare conditions during stunning of pigs with respect to the day of the week.

Proper stunning is important in order to ensure animal welfare and to improve meat quality. The conditions in which the stunning is performed and the result of procedure may vary in practice due to numerous factors. The aim of this study was to examine the effectiveness of the stunning procedure with respect to the day of the week. The experiment was conducted on 100 pigs of different genetic origin and of different age and live weight during 5 working days (20 pigs per day). Stunning procedure was assessed through the following parameters: placing of electrodes at the proper position on the head; application of energized electrodes; voltage, amperage and frequency of the current; duration of current application and interval from stunning to bleeding; presence of tonic, clonic convulsions, as well as rhythmic breathing and re-stunning. In this study, improper electrode placement was observed in 40-70% of pigs, application of energized electrodes in 5-45% of pigs, duration of current application from 6,90 to 17,55 seconds, and the interval from stunning to bleeding from 48,62 to 91,25 seconds, the presence of tonic and clonic convulsions, and rhythmic breathing in 65-85%, 45-75% and 10- 75% of pigs. The stunning procedure was repeated in 5-15% of pigs. In addition, the deterioration of most of the parameters at the end of the week was observed. These results suggest unsuccessful stunning of pigs as a consequence of insufficient staff training, and their fatigue at the end of the week. .

Investigation of the possibility of detection of fluoroquinolones in carp kidney by microbiological diffusion method.

Fish is one of the most valuable food products used in human nutrition, due to the content of proteins, fat, minerals, vitamins, essential n -3 polyunsaturated fatty acids (PUFAs) and cholesterol. To meet the growing needs of the population for this kind of food, fish are increasingly grown in aquaculture. Intensive fish production, due to increased stock density, is favoring the occurrence of bacterial diseases. As a consequence, there is increased morbidity and mortality, reduced growth and reduced leasing sockets materials, which pose a serious problem for the aquaculture and lead to massive use of chemotherapeutics. Antibiotics are the common practice for the treatment of bacterial infections in fish ponds, and flurohinolones are used as antibiotics of choice. Fluoroquinolones are a group of antibiotics that have a broad spectrum of activity, low toxicity and only a few side effects in the treated fish. However, residues of antibiotic in fish tissues represent a real risk to human health. Consumption of fish containing residues of antibiotics can cause allergic, toxic, carcinogenic, mutagenic and teratogenic effects. Therefore, it is necessary to establish the residual amounts of antibiotics in fish tissues, that can be achieved by using reliable laboratory methods and techniques. Because of this, the goal of the work was set to investigate the possibility of identification and quantification of fluoroquinolones in the kidneys of carp by microbiological diffusion method, using the test organism E. coli ATCC 11303. The investigations revealed that microbiological diffusion method enables detection of all five fluoroquinolones (oxolinic acid, enrofloxacin, sarafloxacin, difloxacin and flumequine) in kidney of carp at different maximum residue levels, MRL (100 mg/kg, 100 mg/kg, 30 mg/kg, 300 mg/kg and 600mg/kg, respectively). Identification and quantification of fluoroquinolones at MRL levels was only achieved for enrofloxacin, flumequine and difloksacin. These fluoroquinolones can be detected and quantified at the level below the MRL, i.e. at the level of 1/4 MRL. Contrary to these fluoroquinolones, sarafloxacin can be detected only at the level of 2MRL and oxolinic acid can be detected at the level of 4MRL, as well. EU regulations provide that a screening method can be applicable only if a compound can be detected in the amount of at least at the MRL, and the ½ MRL is recommended. This means that the microbiological diffusion method can be used in routine analytical practice for the identification and quantification of enrofloxacin, flumequine and difloxacin in kidney tissues of carp.