ABSTRACT
The packaging system is one of the factors influencing the preservation of the nutritional value, microbiological safety, and sensory attributes of meat. The study investigated changes in physicochemical and microbiological properties taking place during 15-day refrigerated storage of two calf muscles, the longissimus lumborum (LL) and semitendinosus (ST), packaged in three systems, respectively, vacuum packing (VP), modified atmosphere packaging (MAP, 80% O2 + 20% CO2), and a combined system (VP + MAP, 8 d in VP followed by 7 d in MAP). LL and ST stored in VP had significantly lower levels of lipid oxidation, higher α-tocopherol content, and higher instrumentally measured tenderness in comparison with the samples stored in MAP. On the other hand, the MAP samples had lower purge loss at 5 and 15 days, a higher proportion of oxymyoglobin up to 10 days of storage, and a better microbiological status. Calf muscle samples stored in the VP + MAP system had intermediate values for TBARS and α-tocopherol content and at the same time were the most tender and had the lowest counts of Pseudomonas and Enterobacteriaceae bacteria at 15 days. All packaging systems ensured relatively good quality of veal characteristics up to the last day of storage. However, for MAP at 15 days of storage, unfavourable changes in colour (a high level of metmyoglobin and a decrease in oxymyoglobin, redness and R630/580 ratio) and in the lipid fraction (a high TBARS value and a significant decrease in α-tocopherol content) were observed.
Subject(s)
Food Packaging , Food Storage , Muscle, Skeletal , Red Meat , Thiobarbituric Acid Reactive Substances , alpha-Tocopherol , Food Packaging/methods , Animals , Cattle , alpha-Tocopherol/analysis , Vacuum , Muscle, Skeletal/chemistry , Thiobarbituric Acid Reactive Substances/analysis , Red Meat/analysis , Red Meat/microbiology , Color , Food Microbiology , Myoglobin/analysis , Lipid Peroxidation , Enterobacteriaceae/isolation & purification , PseudomonasABSTRACT
The aim of the study was to evaluate the concentrations of Interleukin-6 (IL-6) in milk and serum of healthy cows (HE) and cows with mastitis caused by Streptococcus spp. The blood and milk samples were obtained from Holstein-Friesian cows (Lublin region, Poland). A total of 43 milk and serum samples from 28 cows with mastitis and 15 healthy cows were selected for study. IL-6 levels in milk from HE cows ranged from 6.09-80.24 pg/mL (median 26.6 pg/mL) and were significantly lower than in milk from both cows with clinical and subclinical mastitis (487.09 pg/mL vs. 26.6 pg/mL in CM, p < 0.001; and 165.31 pg/mL vs. 26.6 pg/mL in SCM, p < 0.001). The IL-6 concentration in the serum of HE was not significantly different from the serum IL-6 of the entire group of mastitis cows, regardless of whether the inflammation proceeded in a clinical or subclinical form (44.37 pg/mL vs. 78.09 pg/mL; 128.29 pg/mL vs. 78.09 pg/mL, respectively). The present study indicates that cows with mastitis caused by Streptococcus spp. develop a local immune response in the mammary gland in response to the pathogen. Monitoring of IL-6 levels in milk can allow early detection of mastitis, which is especially important in cases of subclinical inflammation.