Meat Industry Services – Effect of initial muscle biochemical composition on microbiological growth and eating quality of long aged beef, destined for export markets.

Summary

​Previous vacuum-packaged beef shelf-life studies indicated that microbial growth did not follow the expected pattern and peaked at a lower level than measured in earlier studies.  The current project aimed to determine if initial biochemical properties on sensory properties and microbiological growth.  CSIRO collected samples of vacuum-packed beef striploins from carcases of three different meat colour score ranges – 1b and 1C, 2 and 3, and ≥4, from three export abattoirs in Queensland.  The primal cuts were stored at -1°C for up to 20 weeks and opened for assessment by analysis of microbiological and biochemical properties, and visual and sensory examination at 0, 2, 8, 12, 16 and 20 weeks after packing.
The growth of lactic acid bacteria in the vacuum packs was most highly correlated with objective measurement of meat colour, muscle pH and total glycogen level.  Samples with a pH below 6.1 and a meat colour score less than 4 were acceptable after 20 weeks storage.  Samples with a pH of less than 5.7 had a lower level of microbial growth.