Effect of Vacuum and Modified Atmosphere Packaging on the Shelf Life and Quality of Gutted Rainbow Trout (Oncorhynchus mykiss) during Refrigerated Storage

The quality changes of gutted rainbow trout in vacuum packaging (VP) and modified atmosphere packaging (MAP) with 40% CO2 + 60% N2 (MAP1), 60% CO2 + 40% N2 (MAP2), and 90% CO2 + 10% N2 (MAP3) were evaluated. The samples were stored at 3 ± 0.5 °C, and on days 1, 4, 7, 10, 13, and 16 of storage, microbiological, chemical, and sensory testing was performed. The aerobic plate count (APC) and psychrotrophic bacteria count (PBC) in VP fish exceeded the conventional limit of 7 log cfu/g on day 10, and in MAP1 and MAP2 fish on day 16, whereas in MAP3 fish, their number remained below that limit during the experiment. MAP significantly slowed down the growth of Enterobacteriaceae in trout, and the degree of inhibition increased with increasing CO2 concentration in the gas mixture. The lowest lactic acid bacteria numbers were detected in VP fish, whereas the highest numbers were determined in trout packaged in MAP2 and MAP3. Significantly lower numbers of hydrogen sulfide-producing (H2S) bacteria were detected in fish packed in MAP. Distinct patterns were observed for pH among treatments. The lowest increase in TBARS values was detected in VP and MAP3 fish, whereas in MAP1 and MAP2 fish, the TBARS values were higher than 1 mg MDA/kg on day 16 of storage when a rancid odor was detected. MAP inhibited the increase in total volatile basic nitrogen (TVB-N) content of trout compared to trout packaged in a vacuum. The sensory attributes of trout perceived by the sensory panel changed significantly in all experimental groups during storage. Based primarily on sensory, but also microbial, and chemical parameters, MAP has great potential for preserving fish quality and extending the shelf life of gutted rainbow trout from 7 days in VP to 13 days in MAP1 and MAP2, and to 16 days in MAP3.

Mineral composition and toxic element levels of muscle, liver and kidney of intensive (Swedish Landrace) and extensive (Mangulica) pigs from Serbia

Mineral composition (Fe, Zn, Cu, Mn, Se, Cr, Co, Ni, Na, K, Mg, Ca) and toxic element levels (Cd, Pb, Hg, As) of soil, feed and tissue (muscle, liver and kidney) from intensive (Swedish Landrace, housed indoors, fed a known diet, 4 years) and extensive (Mangulica, free-roaming, non-specified diet, 7-8 months) pigs were determined by inductively coupled plasma mass spectrometry (ICP-MS). Controlled nutrition produced pigs with higher concentrations of most minerals (muscle: Mn, Se, K, Mg; liver: Zn, Cu, Mn, Se, Cr, Ca; kidney: Zn, Cu, Mn, Se, K, Mg), but for Fe the opposite trend was found. Long-term free-ranging pigs have a higher risk of contamination by toxic elements (Cd exceeded the maximum residue level in kidney). Principal component analysis and cluster analysis were used to assess the effect of different pig breed/lifestyle (pig type) on element composition of muscle, liver and kidney of pigs. Multivariate data analysis showed good discriminating capabilities.