Milan Baltic

Correlations among Stress Parameters, Meat and Carcass Quality Parameters in Pigs

Relationships among different stress parameters (lairage time and blood level of lactate and cortisol), meat quality parameters (initial and ultimate pH value, temperature, drip loss, sensory and instrumental colour, marbling) and carcass quality parameters (degree of rigor mortis and skin damages, hot carcass weight, carcass fat thickness, meatiness) were determined in pigs (n = 100) using Pearson correlations. After longer lairage, blood lactate (p<0.05) and degree of injuries (p<0.001) increased, meat became darker (p<0.001), while drip loss decreased (p<0.05). Higher lactate was associated with lower initial pH value (p<0.01), higher temperature (p<0.001) and skin blemishes score (p<0.05) and more developed rigor mortis (p<0.05), suggesting that lactate could be a predictor of both meat quality and the level of preslaughter stress. Cortisol affected carcass quality, so higher levels of cortisol were associated with increased hot carcass weight, carcass fat thickness on the back and at the sacrum and marbling, but also with decreased meatiness. The most important meat quality parameters (pH and temperature after 60 minutes) deteriorated when blood lactate concentration was above 12 mmol/L.

Interdisciplinary Project Bridges the Gap in Electrical Engineers' Knowledge of Modern Control Applications

The aim of this paper is to describe an interdisciplinary student project which combines knowledge and skills from power electronics, control algorithms and digital design. The suggested approach is a group-based project that enables students to develop interdisciplinary knowledge as well as interpersonal and communication skills needed to work in todays multidisciplinary field of modern control applications.

INVESTIGATION OF THE EFFICACY OF IMMUNOCASTRATION AIMED AT THE PREVENTION OF SEX ODOUR IN BOAR MEAT

Disadvantage of meat known as boar taint is caused by steroids, androstenone being of particular importance, as well as indole and its derivatives, among which the best known is skatole. The common practice in Europe, in order to control these changes in meat, is castration without anesthesia. This intervention causes pain and stress to animals, thus undermining animal welfare. Many countries considering animal welfare try to find the alternative solutions in order to avoid castration. The alternative to surgical castration and possible solution to the problem of sex odour in the meat, as well as androstenone and skatole contents decrease in the boars fat is immunological castration of boars (immunocastration). Average skatole content in fat tissue of boars was significantly higher (0.21±0.03 μg/g) compared to skatole content in fat tissue of the castrates, or immunocastrates (0.12±0.02 μg/g). In adipose tissue of the castrates and immunocastrates there was no significant difference in the average content of skatole. The content of androstenone in the adipose tissue of immunocastrates was below detection limits, and the average androstenone level in adipose tissue of boars was 0.66±0.13 μg/g. The obtained results show that immunocastration is justified in consideration of the meat quality and can completely replace castration in male animals, which is in compliance with the preservation of animal welfare in rearing fattening young boars.

Inhibition of Salmonella by thyme essential oil and its effect on microbiological and sensory properties of minced pork meat packaged under vacuum and modified atmosphere

The antibacterial activity of thyme essential oil (TEO) was evaluated against four serovars of Salmonella (S. Enteritidis, S. Typhimurium, S. Montevideo and S. Infantis), experimentally inoculated (106CFU/g) in minced pork, which was treated with different concentrations of the TEO (0.3%, 0.6% and 0.9%) packaged under vacuum or MAP (30%O2/50%CO2/20% N2) and stored at 3±1°C for 15days. GC-MS analysis of the TEO was performed in order to determine composition, and the predominant constituent was thymol (50.48%), followed by p-cymene and linalool. The minimum inhibitory concentration was determined for each Salmonella serovar studied. Among the tested active compounds, thymol and carvacrol exhibited the greatest inhibitory effect followed by TEO, with minimum inhibitory concentrations of 320 to 640μg/ml. S. Enteritidis was the most sensitive serovar. During the storage period, Salmonella counts in pork were reduced by 1.69-4.05logCFU/g. The influence of TEO on Enterobacteriaceae, lactic acid bacteria and total viable count was determined in control mince with no added Salmonella. The most pronounced antibacterial effect was achieved by the combination MAP and 0.9% TEO. Although the antibacterial activities of all studied concentrations of TEO in pork were evident and significant (P<0.05), sensory analysis showed that 0.3% TEO was the most acceptable to trained panellists.

Effect of lairage time, behaviour and gender on stress and meat quality parameters in pigs.

The objective of this study was to determine the effects of lairage time (short vs. long), behavior (aggressive vs. non-aggressive) and gender (gilts, barrows and boars) on stress and meat quality parameters in pigs (n = 100). In the group with short lairage, aggressive behavior of gilts and boars was observed. At exsanguination, blood samples were collected and levels of blood lactate and plasma cortisol were determined. Post mortem pH value, temperature, drip loss, sensory and instrumental color and meat quality class were determined on the muscle Longissimus dorsi. Higher blood lactate concentration (P < 0.05) and skin blemish score (P <0.001), lower temperature (P < 0.05) and drip loss (P < 0.01), as well as darker, less red and yellow meat color (P < 0.001) were found after long lairage compared to short lairage. Gilts had higher plasma cortisol concentrations than barrows (P < 0.05), while barrows had lower skin blemish scores (P < 0.05) than gilts and boars after long lairage. The highest incidence of PSE (pale, soft and exudative) meat was observed in barrows (100.00%) and boars (91.67%) after short lairage, while the lowest incidence of PSE meat was found in barrows (28.89%) after long lairage. Aggressiveness affected meat temperature, as aggressive pigs had higher meat temperature (P < 0.05) than non-aggressive pigs.

Corrigendum to “The effects of dietary Selenium-yeast level on glutathione peroxidase activity, tissue Selenium content, growth performance, and carcass and meat quality of broilers”

Abstract The present study was conducted to assess effects of selenium (Se)‐yeast supplementation on glutathione peroxidase activity, Se levels in tissues, growth performance, carcass, and meat composition in broilers. A total of 275 one‐d‐old Cobb 500 broilers of both sexes were randomly allotted to 1 of 5 treatments during a 42‐d period. The 5 treatments differed only in Se content: group 1 had no additional Se (background only); groups 2, 3, and 4 received 0.3 mg/kg of added Se from the beginning of the trial until d 21, whereas in the second half of the study (from d 22 to 42), these groups received 0.3, 0.6, and 0.9 mg/kg of added Se, respectively; and group 5 received 0.9 mg/kg of Se for the entire experimental period. At the end of the study, the control group showed significantly lower (P < 0.01) glutathione peroxidase activity in blood plasma compared to Se‐supplemented groups. Regarding Se concentration in various tissues, the groups receiving Se yeast showed higher plasma, feces, and meat Se contents than the control group (P < 0.01). Supplementation of Se improved broilers’ body weight, weight gain and feed conversion ratio (P < 0.01). Dressing percentage was lower in the control group and the group with 0.3 mg/kg of added Se compared to other experimental groups (0.6 and 0.9 mg/kg of dietary Se). The proportion of less valuable carcass parts (wings and legs) was higher (P < 0.01) in the group fed the basal diet compared to groups supplemented with 0.9 mg/kg of Se. Initial and ultimate pH values differed among experimental groups (P < 0.05). Supplementation of Se improved the broilers antioxidative resistance, growth performance, carcass quality, and chemical composition of meat.

Nanotechnology: Meat Safety Revolution

Since the need for safe, high nutritional food such as meat increases, the need to control and improve its safety also increases. Regardless of implementation of HACCP, constant monitoring, and improvements in slaughter and processing hygiene, meat safety is still an important issue from the health and economic points of view. Meat contamination may occur during all stages of production from farm to fork. Many preservation techniques are used to prevent the occurrence of food-borne diseases and control meat deterioration. Nanotechnology, involving characterization, fabrication, and manipulation of structures and inorganic or organic materials at sizes below 100 nm, is one of the innovative technologies applied in a number of science areas including food science. At the moment, nanotechnology is mainly focusing on food packaging, but nanotechnology can apply to the whole food chain presenting an excellent opportunity to detect and control pathogens, some toxins, and heavy metals; to monitor meat spoilage and extend meat shelf life; and in that sense to revolutionize the global approach to meat and, in general, food safety. Furthermore, after overcoming some obstacles in the term of regulations and safety, it can meet growing consumer demands in an acceptable and cost-effective manner.

Effect of modified atmosphere and vacuum packaging conditions on selected chemical and physico-chemical parameters of marinated and salted Atlantic mackerel (Scomber scombrus)

Chemical and physico-chemical parameters of marinated and salted Atlantic mackerel (Scomber Scombrus), with emphasis on the quality and safety parameters in modified atmosphere packaging (MAP) and vacuum packaging (VP), were investigated. Quality assessment of mackerel stored in MAP (40% CO2+60% N2) and VP for up to 50 days at 4±1 °C was done by the monitoring of pH value, total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA) and histamine. The pH value of fish meat was significantly lower in the marinated samples. The highest concentration of TVB-N was recorded in the salted mackerel stored under VP whereas the lowest TVB-N in the marinated mackerel stored under MAP conditions. The formation of TBA increased with the time of storage and was the lowest in the marinated mackerel stored in MAP. The concentration of histamine increased during storage and its level reached over 10 mg/100 g for the salted mackerel stored under VP conditions. The marinated mackerel packed in MAP had extended shelf life at 4±1 °C compared to that packaged in VP according to physico-chemical analysis.

Variable sample rate acquisiton platform

This paper presents a solution for hardware platform for signal acquisition with variable sampling rate. The system is designed to work in noisy environment near power distribution grid with variable frequency.