High‐Oxygen and Carbon Monoxide Packaging Enriched With CO ₂ for the Shelf‐Life Prolongation of Chilled Pork: Dynamic Analysis of Microbiota and Physicochemical Profiles

This study investigated the influences of various CO 2 concentrations on the microbiological and physicochemical quality of high‐oxygen and carbon monoxide packaged pork steaks during chilled storage. Based on the commercial HiOx‐MAP 1 (70% O 2 /30% CO 2 ) and CO‐MAP 1 (0.4% CO/30% CO 2 /69.6% N 2 ), the novel HiOx‐MAP 2 (40% O 2 /60% CO 2 ) and CO‐MAP 2 (0.4% CO/60% CO 2 /39.6% N 2 ) were formulated by elevating CO 2 levels from 30% to 60%. CO‐MAP demonstrated more advantages over HiOx‐MAP in maintaining meat colour and lipid and protein oxidative stability. HiOx‐MAP and CO‐MAP enriched with the same CO 2 levels exhibited similar total viable counts in pork steaks, regardless of O 2 levels. Increasing CO 2 levels in both HiOx‐MAP and CO‐MAP significantly reduced bacterial counts and total volatile basic nitrogen accumulation, but negatively affected the colour of HiOx‐MAP pork. HiOx‐MAP 2 even exhibited a stronger antibacterial potential than the anaerobic CO‐MAP 1, owing to the effective control of total viable counts by the higher level of CO 2 , whereby CO 2 ‐mediated microbiota development relied on the presence or absence of O 2 . In contrast to the most dominant Brochothrix thermosphacta under HiOx‐MAP 1, Photobacterium phosphoreum prevailed in other MAP systems. Leuconostoc and Serratia were detected in higher levels in pork held under CO‐MAP 1 and HiOx‐MAP 2, respectively. Overall, both HiOx‐MAP 2 and CO‐MAP 2 provide better microbial and quality stability than both commercial MAP systems and represent an alternative approach for the shelf‐life extension of chilled pork.