Scanning and transmission electron microscopy of normal and PSE porcine muscle

Structural differences between normal and pale, soft, exudative (PSE) longissimus dorsi (LD) muscle from purebred and crossbred pigs were observed using scanning and transmission electron microscopy. The effect of severe freeze-thaw contraction on the muscle samples was observed. The membranes of many different organelles (sarcoplasmic reticulum, mitochondria, sarcolemma and connective tissue) appeared markedly disrupted after cryofracture of PSE muscle with frequent breaks especially near the Z-lines. In addition, there was little definition of the M-line and H-zones in either the PSE or intermediate animals.