Lactate Dehydrogenase Activity as an Endpoint Heating Indicator in Cooked Beef

Abstract

ABSTRACTLactate dehydrogenase (LDH, E.C. 1.1.1.27) activity, specifically LDH5 isoenzyme, declined significantly when bovine Semimembranosus (SM) slurries were heated from 57° to 66°C. When SM whole muscle roasts were brine pumped and oven‐cooked, total LDH and specific activities declined proportionately from 57° to 63°C resulting in almost no activity at 63°± 0.5°C. LDH activities were consistently higher in younger cattle and lower in older cattle for SM, Infraspinatus (IN) and Longissimus dorsi (LD) muscles and were lowest overall in the IN. LDH colorimetric and fluorescent assays were more accurate indicators for predicting beef roast heating temperature endpoints between 60° and 63°C than the USDA‐FSIS method.