The oxidation status of three types of duck meat (conventional, organic, wild) during refrigerated storage under air and vacuum-packaged atmospheres.

1. This study evaluated and compared the oxidation status of meat from conventionally-farmed, organic and wild ducks during chilled storage in air or vacuum packaging. In total, 48 carcases from each group of ducks were investigated, and 24 carcases from each type of production were stored under vacuum or in air at 3°C ± 1°C. Sample analyses were conducted after 1, 3, 6 and 9 d of storage.2. The antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl: DPPH), thiobarbituric acid reactive substances (TBARS) and free fatty acids in the breast, thigh and wing muscles were determined.3. The antioxidant capacity of meat from conventional ducks was higher than that from organic and wild ducks. The muscles of organic and wild ducks were more susceptible to secondary oxidation (particularly when stored in air) than conventionally-raised birds. The free fatty acid levels in samples of breast and thigh meat from wild ducks on the last day of storage were higher than in conventional and organic ducks.4. The results showed that the oxidation status of meat from conventional ducks was more stable during refrigerated storage than the meat of organic and wild ducks.

Microbiological quality of organic chicken meat during refrigerated storage in air and modified atmospheres.

1. The aim of this study was to assess the incidence of pathogens and the development of spoilage microflora in organic chicken meat originating from a small poultry slaughterhouse and stored for 14 days at 2°C aerobically (control) or in one of two modified atmosphere packaging systems (MAP1: 80% O2, 20% CO2 and MAP2: 70% N2, 30% CO2). 2. Campylobacter jejuni survived well during storage; and was found on the skin in 95% of samples (262/276). 3. In general, both the skin and meat samples showed a good initial microbiological quality with total viable counts of less than 3 log cfu/g in meat and approximately 5 log cfu/g on skin. 4. No difference was found between breast and thigh samples during the experiment. 5. Shelf life was limited mainly by the development of mesophilic and psychrotrophic microflora on skin which were found at 7-day storage for the control and MAP1 and 10 days for MAP2.

Effect of modified atmosphere packaging on the course of physical and chemical changes in chilled muscle tissue of silver carp (Hypophthalmichthys molitrix, V.).

The effect of two types of modified atmosphere (MA1: 69% N2, 25% CO2, 5% O2, 1% CO; MA2: 70% N2, 30% CO2) on changes in physical and chemical parameters (pH, a(w)--water activity, TVBN - total volatile basic nitrogen, TMA - trimethylamine, FFA - free fatty acids, PV - peroxide value, TBA--thiobarbituric acid) in muscle tissues of the silver carp was monitored in the study. The samples were stored at temperatures +2 +/- 2 degrees C for 18 days. Changes in gas volumes (CO2 and O2) in MAs were also monitored. CO2 levels increased in MA1 but decreased in MA2. At the end of 18 days of storage, a significantly (P < 0.01) lower water activity (a(w)) levels were found in samples packaged under MA1, in contrast to samples packaged under MA2 where water activity values showed considerable fluctuation. Variations in pH values in the two types of MA showed similar trends. Sample pH gradually decreased until day 9 of storage. On day 11, muscle tissue pH increased markedly and then began to decrease again. The overall decrease in pH values was more profound in samples packaged under MA1. TVBN and TMA levels in samples packaged under the two types of MAs remained almost identical until day 9 of the experiment. Later, however, significantly (P < 0.01) higher levels of both parameters were found in muscle tissues packaged under MA1. FFA concentrations in silver carp samples in MA1 were significantly lower (P < 0.01) throughout the experiment. The PV increased significantly in both muscle samples tested. Greater fluctuations in this parameter's values throughout the experiment were observed in samples packaged under MA2. Faster rates of oxidation (P < 0.01) were found in samples packaged under MA1 starting on day 9. Maximum TBA values in MA1 and MA2 were observed on days 14 and 18 of the experiment, respectively. From the course of proteolytic and oxidative changes point of view, the more appropriate combination of gases for silver carp storage seems to be the mixture of 70% N2 and 30% CO2 (MA2), which allows for muscle storage of up to 9 days. We recommend TVBN as a suitable indicator of freshness, and TBA assay as a suitable indicator of the extent of oxidative processes.

Selenium from Se-enriched lactic acid bacteria as a new Se source for growing-finishing pigs.

The goal of the trial was to determine the efficacy of Se from Se-enriched lactic acid bacteria in accumulation of Se in the muscle tissue and to evaluate its effect on meat quality in finisher pigs. In group I (n = 12) the feed was supplemented with inorganic sodium selenite, in group II (n = 12) with Se from Se-lactic acid bacteria, in group III (n = 12) with Se from Se-enriched yeast and pigs in group IV (n = 11) were fed non-supplemented basal diet. The experimental feed mixtures were supplemented with 0.3 mg Se per kg and were fed for a period of 3 month before slaughter. The use of Se from Se-enriched lactic acid bacteria resulted in comparable accumulation of Se in the muscle tissue as with sodium selenite, and in lower accumulation in comparison with Se from Se-enriched yeast. We did not find any differences in parameters of meat quality among experimental groups. It is concluded that Se from Se-enriched lactic acid bacteria has a comparable accumulation in the muscle tissue as sodium selenite and it does not negatively influence the meat quality.

Chemical, instrumental and sensory characteristics of cooked pork ham.

Instrumental, chemical and sensory parameters of cooked pork ham were evaluated. Principal component analysis was carried out on the basis of the instrumental variables related to colour and texture. The four PCs account for almost 94% of the total variance in the data set. The PCA only separated 3 hams with a(∗)>10. Hardness was correlated with non-collagen muscle protein (P⩽0.01), gumminess (P⩽0.01) and ash (P⩽0.05). Sensory evaluated tenderness showed positive significant correlation with L(∗) (P⩽0.01). The most important colour parameter seems to be a(∗), which was negatively correlated with sensory evaluated parameter colour (P⩽0.01). The PCA performed on all parameters (sensory, chemical and textural) discriminated two groups of hams differing in non-collagen muscle protein content and hardness.