Retail Shelf-Life of Pork Dipped in Organic Acid before Modified Atmosphere or Vacuum Packaging

Modified atmosphere packaging (MAP) is increasingly popular for meat, but raw, chilled pork in vacuum or anoxic environments has a purple color. The retail shelf-life of pork chops dipped in 500 ppm ascorbic acid, 250 ppm citric acid, or no acid dip and stored at 1 degrees C before simulated retail display in MAP with gas exchange or air-permeable packaging after vacuum pouch storage was determined. The 80% N-2:20% CO2 in MAP was exchanged with 80% O-2:20% CO2, and chops were removed from vacuum packages and overwrapped with permeable film (VP-PVC) on the 7th day before simulated retail display at 4 C. Shelf-life traits were determined at 1, 7, 8, 10, 12, and 14 d postpackaging. The pH values changed with time; but returned to Post-dipped, prepackaged levels at the end of simulated retail storage. Weight loss of chops increased (P < 0.05) in VPPVC compared with MAP The a* values increased (P < 0.05) and L* and b* values decreased during simulated retail display, with higher L*, a*, and b* color values for chops in MAP than VP-PVC. Log numbers of psychrotrophic microorganisms were higher (P < 0.05) on VP-PVC samples than for chops in MAP on days 12 and 14. Psychrotrophic counts on ascorbic acid-treated samples were decreased compared with citric acid or no dipping on pork during simulated retail display. Pork chops in MAP with gas exchange had lighter and redder color, increased weight retention, decreased psychrotrophic counts, and increased lipid oxidation compared with conventional vacuum and overwrap packaging systems:.