Polybrominated biphenyl congener levels and distribution patterns in raw and cooked beef.

The retention and distribution of eight polybrominated biphenyl (PBB) congeners were studied by roasting beef sirloin tip samples to an internal temperature of 65 degrees C, braising and broiling adductor and semimembranosus steaks to an internal temperature of 77 degrees C, broiling ground round and hamburger patties 77 degrees C, and comparing cooked values with those in the raw. Rounds were obtained from four Holstein cows with known PBB contamination. Significant reductions in PBBs occurred with cooking of all cuts. Roasting sirloin tips reduced the PBBs by 45.7%. Broiling reduced PBBs as follows: Adductor steaks (53.2%), semimembranosus steaks (71.2%), ground beef patties (32.3%) and hamburger patties (31.5%). Braising reduced PBBs in the adductor steaks by 37.2% and in the semimembranosus steaks by 34.9%. The distribution of PBB congeners was also affected by cooking in all cuts except hamburger. The proportion of 2,4,5,2',4',5'-hexabromobiphenyl decreased upon cooking but the change in the proportion of 2,3,4,5,2',4',5'-hepatbromobiphenyl varied with the cut used. Both of these isomers are known to be phenobarbital type inducers. The proportion of 2,4,5,3',4'5'-hexabromobiphenyl, which both a 3-methylcholanthrene and phenobarbital type inducer, increased in the roasted sirloin tip surface and broiled ground round patties.