The use of hormonal or non-hormonal agents in livestock is widespread among the greatest meat producers, as the U.S.A., Australia, Canada, Argentina and others. These agents include diethylstibestrol (DES), which is banned, and zeranol, which is controlled. Both substances improve live weight gain, carcass weight, feed conversion and meat percentage. Their use, however, may cause residues presence in tissues and organs of livestock, which, in turn, represents a potential hazard for human health. For this reason, many countries, including Brazil, do not allow their use. This trial aimed at verifying whether beef collected between July 1993 and November 1994 in Brazilian slaughterhouses was in accordance with the current legislation in regard to the above mentioned anabolic substances. Four hundred and sixteen samples of liver were searched for DES and 385 for zeranol presence by radioimmunoassay (RIA). DES was detected in no samples (p > 0,05) on the other hand zeranol was detected in two (p < 0,05). Zeranol presence was confirmed by gas cromatography-mass spectrometry (p < 0,05). Average recoveries obtained for DES were 62,6% ± 5,7 in the extractive phase (³H-DES) and 83,8% ± 16,8 in the extractive phase plus RIA (DES). As to zeranol, average recoveries were 63,0% ± 5,8 in the extractive phase (³H-zeranol) and 94,8% ± 13,8 in the extractive phase plus RIA (zeranol). Therefore, it is concluded that Brazilian cattle meat is in accordance with current legislation in regard to DES; it is not, however, in regard to zeranol for it was found in 0,52% of samples.
anabolics; beef cattle; residues; monitoring; radioimmunoassay; mass espectrometry
