Determination of salable shelf-life for wrap-packaged dry-aged beef during cold storage

Abstract

We investigated microbial and quality changes in wrap-packaged thy-aged beef after completion of aging and subsequent storage in a refrigerator. After 28 days of dry aging (temperature, 4 degrees C; RH, approximately 75%; air flow velocity, 2.5 m/s), sirloins were trimmed, wrap-packaged, and stored at 4 degrees C for 7 days. Analyses of microbial growth, pH, volatile basic nitrogen (VBN), 2-thiobarbituric acid-reactive substance (TABRS), and instrumental color, myoglobin, and sensory evaluation were conducted on days 0, 3, 5, and 7. The results show that the number of total aerobic bacteria (TAB), yeast, and lactic acid bacteria increased with an increase in storage days, whereas no change in the growth of mold was observed during 7 days of storage. Based on the legal standard for TAB count, the estimated shelf-life of wrap-packaged dry-aged beef was predicted to be less than 12.2 days. However, the shelf life should be less than 6.3 days, considering the result of sensory quality (odor, taste, and overall acceptance). No significant change in visible appearance was also observed during 7 days of storage. The results suggest that the present quality indicators for meat spoilage (pH, VBN, and TBARS) should be re-considered for dry-aged beef, as its characteristics are different from those of fresh and/or wet-aged beef.