EFFECT OF MICROBIAL GROWTH UPON SARCOPLASMIC AND UREA-SOLUBLE PROTEINS FROM MUSCLE

SUMMARY– A comparison of starch gel patterns of sarcoplasmic proteins from aseptic and inoculated porcine and rabbit muscles after storage for 0, 8 and 20 days at 10°C indicated that different microorganisms preferentially utilized specific proteins. Pseudomonas fragi showed the greatest amount of proteolytic activity upon the sarcoplasmic fraction, causing extensive breakdown in both rabbit and porcine muscle. Leuconostoc mesenteroides caused extensive alteration in the sarcoplasmic proteins of rabbit muscle, but had less effect upon porcine muscle. Pediococcus cerevisiae exhibited similar action to L. mesenteroides upon rabbit muscle sarcoplasmic proteins, but had no effect upon pig muscle. Micrococcus luteus showed only minor breakdown of rabbit muscle sarcoplasmic proteins, and had no action upon porcine muscle. Both P. fragi and P. cerevisiae caused considerable breakdown of the urea-soluble proteins in pig muscle and to a lesser extent in rabbit muscle. Neither M. luteus nor L. mesenteroides exerted any measurable proteolytic effect upon the urea-soluble proteins. Possible implications concerning meat spoilage are discussed.