Technical Note: Comparison of myofibril fragmentation index from fresh and frozen pork and lamb longissimus 1,2

The myofibril fragmentation index (MFI) is strongly associated with indices of meat tender- ness, such as Warner-Bratzler shear force and sensory tenderness. The MFI is normally determined on fresh muscle. It is not known whether this index can be deter- mined on frozen muscle. The objective of this experi- ment was, therefore, to determine whether there is a difference between MFI values of fresh and frozen lamb and pork longissimus. To compare the effect of freezing on MFI, longissimus samples were obtained from eight