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.