Use of organic acids to improve the chemical, physical, and microbial attributes of beef strip loins stored at -1 degrees C for 112 days

Twenty-one beef strip loins (Institutional Meat Purchasers Specification #180) were cut into equal halves. One-half of each loin was sprayed with a mixture of 2% lactic acid and 2% (vol/vol) acetic acid and the corresponding half was used as a control. The strip loins were stored at -1 degrees C for 0, 7, 14, 28, 56, 84, or 112 days and evaluated for chemical, physical, and microbial properties. The internal pH increased significantly (P < 0.05) beginning at day 56 for all products. Vacuum scores and visible purge scores showed that these qualities became less desirable over storage time. There were no significant differences (P > 0.05) for meat color, fat color, or odor over storage time. Acid-treated strip loins had significantly lower (P < 0.05) visible purge scores than control strip loins. Internal and external pH, vacuum, meat color, fat color, and odor were not affected by acid treatment. In a calculation of time-by-treatment interaction (P < 0.05), acid-sprayed strip loins had less percentage of purge than corresponding controls at 56 and 112 days of storage. Water-holding capacity decreased over 84 days of storage. Anaerobes, lactic acid-producing bacteria, and psychrotroph populations increased significantly (P < 0.05) over storage time but anaerobes and lactic acid-producing bacteria were reduced by acid treatment. Acid-sprayed strip loins had significantly lower aerobic (P < 0.05) and psychrotrophic (P < 0.1) populations than controls after 14 days. These data indicate that an acid spray immediately prior to packaging can reduce some species of bacteria without adversely affecting the physical properties of products stored for 112 days at -1 degrees C.