Microbiological and physicochemical quality changes of pork ham slices packed using various methods during long-term refrigerated storage

The research focused on assessing the alterations in the quality of pork ham slices packaged using various methods and stored for 28 days under refrigerated conditions (0–4 °C). The meat was packed in modified atmosphere packaging (MAP): MAP80/20 (80 % O 2 /20 % CO 2 ), MAP70/30 (70 % O 2 /30 % CO 2 ), MAP60/40 (60 % O 2 /40 % CO 2 ), MAP50/50 (50 % O 2 /50 % CO 2 ), vacuum skin packaging (VPS), and regular vacuum packaging (VP). The microbiological and physicochemical properties of pork ham were monitored throughout its long-term storage. Over the storage time, drip loss in packages increased, pH level decreased from 5.8 to 5.5 (irrespective of the packaging method). Higher O 2 content in packages significantly increased lightness (L∗) of meat (without influence on redness – a∗ color parameter) and TBARS index values. VPS and VP meat were less microbiologically stable (including the growth of psychotropic bacteria) than MAP meat. VPS meat exceeded the allowable total plate count for fresh meat (10 7 cfu/g) on day 14 and VP and MAP80/20 meat on day 28 of storage. The O 2 deficiency (VP and VPS) and its excessively high content (MAP80/20) in packages shortened shelf-life of meat. Due to more stable gas composition, microbiological quality, and color of pork ham slices, the MAP60/40 packaging method can be recommended. • Pork slices were packed in MAP with various gas mixtures, in VP and in VSP. • Microbiological and physicochemical quality of meat were evaluated. • Higher O 2 content in packages significantly increased TBARS index values. • VPS and VP meat were less microbiologically stable than MAP meat. • O 2 deficiency and its excessively high content shortened shelf-life of pork.