Evaluation of the illegal use of clenbuterol in Portuguese cattle farms from drinking water, urine, hair and feed samples

Abstract

The recent discovery of clenbuterol contamination in Portuguese food led to the specific inspection of 16 cattle farms for beta-agonists, involving the analysis of a total of 486 samples (78 feed, 106 drinking water, 168 urine and 134 hair). The samples were screened for the beta-agonists: bromobuterol, cimaterol, clenbuterol, clenpenterol, clenproperol, hydroxymethylclenbuterol, mapenterol, salbutamol and terbutaline. Only clenbuterol was found in all analyzed matrices and the most likely method of illegal administration to animals was through drinking water. Of all samples analysed, 14.15% of drinking water were found positive in the range 0.03-3.80 mg l(-1) clenbuterol. Inclusion of hair samples in the Portuguese plan for clenbuterol residue control in live animals is discussed.