Effect of muscle type, salt and pH on cooked meat haemoprotein formation in lamb and beef

The rate of cooked meat haemoprotein formation, measured as the rate of los s of myoglobin solubility, in lamb was dependent on the muscles anatomical location and temperature. Lamb longissimus dorsi musle at 55 to 70 degrees C formed cooked meat haemoprotein more rapidly than the muscles in the shou lder and leg. The formation in lamb was more rapid than in beef The rate in high pH beef (7.25) l. dorsi was lower than found in beef l. dorsi of norm al pH but in low pH lamb (5.38) l. dorsi the rate was, at most temperatures , also slower than found in this muscle from lamb of normal pH. In the pres ence of NaCl the rate of cooked meat haemoprotein formation was faster (alm ost doubled at 2g/100g meat) than found in the corresponding salt free lamb and beef samples. Other additives commonly added to meat products (mechani cally recovered meat, oil, polyphosphates, soya, whey and caseinate) had li ttle effect on the rate of cooked meat haemoprotein formation, at the level s normally used in meat products. It is concluded that for lamb products li ttle if any myoglobin will remain soluble, and the products will look cooke d before the recommended thermal treatment to inactivate Escherichia coli O 157:H7 has been achieved. (C) 1999 Elsevier Science Ltd. All rights reserve d.