The quality of aged beef and aged-then-frozen lamb meat after up to 2 years of frozen storage at −12 or −18 °C

This study investigated the effect of 2 years frozen storage at −12 or −18 °C on aged beef and aged or unaged lamb meat quality. The first study compared 5-week aged longissimus lumborum muscle (LL) frozen for 0 (unfrozen), 1 or 2 years at either frozen storage temperature (n = 24, 4 samples per frozen storage period/temperature combination). Shear force was higher for frozen beef than unfrozen beef (P = 0.025). Sarcomere length, ultimate pH, cooking loss, purge loss, and total loss were higher for unfrozen beef compared to frozen beef. There were no frozen storage period effects on the population of Brochothrix thermosphacta, Clostridium perfringens, E. coli, Enterobacteriaceae sp., and lactic acid bacteria (LAB) – all microorganisms, excluding LAB, were at levels below their respective levels of detection. Both −12 and −18 °C preserved beef to comparable levels of quality, irrespective of the frozen storage duration. The second study compared 0- and 8-week aged lamb that was subsequently frozen for 2 years at either frozen storage temperature (n = 24, 6 LL per chilled storage period/frozen storage temperature combination). Particle size and shear force were lower for 8-week aged lamb. There were no differences in the quality of lamb meat held at −12 and −18 °C for 2 years, with all the samples of comparable and acceptable quality. These findings demonstrate that 2 years of frozen storage at −12 °C is viable for aged cuts of red meat and provides comparable quality to a colder (−18 °C) frozen storage temperature.