HEAT INACTIVATION OF TYLOSIN INCLUDED IN MUSCLE TISSUE AND METHOD OF ITS PREVENTION

TOMIYAMA et al2) reported previously that tylosin could be heat-inactivated both in solution and in tissues by ferric iron and/or autoxidized oil and be prevented from its inactivation by the addition of isoamylgallate and chelating agents. YOKOSEKI et al3), however, pointed out a possibility that the decrease in tylosin on heating various tylosin-containing muscle tissues might be due to the adsorption of tylosin on protein coagulum. The present data clearly indicated that tylosin included in fresh muscle tissue could be inactivated upon heating by the reaction with reducing group(s), most probably sulfhydryl group in situ or formed on heating the tissue (Tables 2, 10 and 11). This type of inactivation was inhibited by the presence of oxidizing agents (Tables 7 and 8). A possibility of leaving some tylosin activity adsorbed on protein coagulum of muscle tissue can be eradicated by the present result showing that an added amount of tylosin was nearly completely recovered in a non-coagulable part of the tissue by heating it with potassium bromate at pH 7 (Table 12).