Animal Science Department


Date of this Version

January 1999


Published in 1999 Nebraska Swine Report, compiled by Duane E. Reese, Associate Professor and Extension Swine Specialist, Department of Animal Science. Prepared by the staff in Animal Science and cooperating Departments for use in Extension, Teaching and Research programs. Published by Cooperative Extension Division, Agricultural Research Division, and Institute of Agriculture and Natural Resources at the University of Nebraska-Lincoln.
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The effects of storage time, packaging atmosphere and raw material source on shelf-life of fresh ground pork were studied. Fresh ground pork (18 percent fat) was packaged in an atmosphere of 80:20 percent 02:CO2 or 100 percent CO2 and placed in unlighted refrigerated storage (34°F) for a period of two or eight days to simulate distribution time of the product from manufacturer to retail merchandiser. Products were then placed under lighted storage for eight additional days (100 foot candles, 34°F) to simulate retail display conditions. Ground sirloin had higher percent surface metmyoglobin (darkness and brown color) than ground pork shoulder after eight days of lighted storage. Lipid oxidation (rancidity) was higher in ground pork shoulder than ground pork sirloin. Pork shoulder had higher a* (redness) values than pork sirloin in both atmospheres. Microbial loads (aerobic microorganisms) were higher in product stored eight days versus two days; however, total aerobic microbial loads did not exceed 106 (the level commonly used to indicate microbial spoilage) for product stored in either atmosphere. Carbon dioxide successfully extends product shelf-life up to eight days under lighted storage conditions.