Commercially produced vacuum
packaged, fully cooked, microwaveable beef
roasts from four producers were purchased
from local retail markets. Salt concentration,
pH, water activity (aw), and percent moisture,
fat and protein were determined. Samples of
both package juice and homogenized beef
plus juice were analyzed for the presence of
aerobic, anaerobic and lactic acid bacteria
and clostridia-type organisms. The cooked
beef products had pH values from 5.82 to
6.19, water activity of 0.992 to 0.997, and
contained 0.34 to 1.07% salt, 61.89 to
72.39% moisture, 4.29 to 18.21% fat and
15.92 to 20.62% protein. No growth was
detected in juice for aerobic, anaerobic or
lactic acid bacteria or clostridia-type
organisms. Combined beef and juice had
less than 2 CFU/g for aerobic, anaerobic or
lactic acid bacteria or clostridia-type
organisms. Cooking and chilling schedules
used in the manufacture of the four products
we evaluated in this study limited survival
and outgrowth of microorganisms.
