EVALUATION OF A RAPID METHOD FOR MEASUREMENT OF CATALASE ACTIVITY IN COOKED BEEF AND SAUSAGE

Catalase (CAT) activity in ground beef and pork was determined on samp les cooked from 60 to 71.1 degrees C. One-gram samples of ground round (4% fat), hamburger (24% fat), and commercial pork sausage (38% fat) were cooked in a controlled-temperature waterbath at 65, 68.3, and 71 degrees C. Chilled samples were immersed in direct contact with the co oking water; the test samples were removed every 15 s and immediately immersed in an ice-water bath (0 to 1 degrees C) to quick-chill the sa mples to prevent temperature over-run. Samples retained high (HMB valu e 20+, over range) CAT activity through 90, 60, and 45 a at 65, 68.3, and 71 degrees C, respectively, before showing rapid activity decrease s. Four USDA-FSIS approved meat patty heating processes (66.1 degrees C, 41 s; 67.2 degrees C, 26 s; 68.3 degrees C, 16 a; and 69.4 degrees C, 10 s) were analyzed for CAT activity. CAT activity in meat frozen p rior to cooking was slightly lower (P < 0.05) than in nonfrozen meat. CAT activity decreased (P < 0.05) among meat treated at 66.1 degrees C for 41 s, at 67.2 degrees C for 26 s, and at 68.3 degrees C for 16 s, but the treatment at 68.3 degrees C for 16 s was not different (P < 0 .05) from that at 69.4 degrees C for 10 s. These results show this rap id (20 to 25 min) CAT activity test could be used to establish activit y values at specific end-point temperatures for model heat-processed g round beef or sausage products and may be useful to USDA FSIS process inspectors and food processors in quality assurance and HACCP (hazard analysis critical control points) programs for thermal input verificat ion.