Effect of time and method of aging on the microbiological quality of beef loins and corresponding steaks

Newsome, R.L.; Langlois, B.E.; Moody, W.G.; Gay, N.; Fox, J.D.

Journal of Food Protection 47(2): 122-125


Cattle (24) were slaughtered at a commercial packing plant, the carcasses were chilled for 72 h at 4.degree. C and then fabricated into wholesale cuts. Right loins were vacuum packaged and aged for 1, 3 and 5 wk at 4.degree. C while the left loins were aged conventionally for 1, 2 and 3 wk at the same temperature. Core samples were removed from both ends of the loins and were analyzed using standard microbiological procedures. Loins were cut into 2.54-cm thick steaks wrapped in O2-permeable fresh meat wrap and placed at 4.degree. C in a simulated meat case. On days 1, 3 and 7 steaks were evaluated using the same microbial technique used for loins. Counts were similar for conventionally and vacuum-aged loins after aging 1 wk. After 3 wk of aging, the vacuum-aged loins had higher (P < 0.05) coliform, anaerobic, streptococcus and lactobacillus counts. In addition to these counts, the aerobic counts (20.degree. and 35.degree. C) of vacuum-aged loins increased (P < 0.05) after an additional 2 wk of aging. Counts of steaks from 1 wk old loins generally were not different as a result of method of loin aging. Lactobacillus counts of steaks from 3 wk old loins differed as a result of method of aging. Except for higher lactobacillus counts, counts of steaks from 5 yr old vacuum aged loins were similar to the counts of steaks from loins which were vacuum-aged for 3 wk.