TRICHOMONADS AS TEST ORGANISMS IN THE DET ERMINATION OF RESIDUES OF HISTOMONASTATICS

The effect of nitroimidazoles on cultures of trichomonads was examined . A concentration of approximately 0.5 mg metronidazole and 1.0 mg ron idazole per liter serum was sufficient to kill the test cultures. Thus , this method is applicable for animals-still under treatment. Extract ion and concentration procedures increased the sensitivity of the meth od to 0.25 ppm for.ronidazole and metronidazole and to 0.125 ppm for d imetridazole. Considering the distribution of these substances in plas ma and muscle tissue, which is approximately 3 : 1, the blood test is a sensitive method for estimating the tissue concentration. Therefore, this test systems appears to be particularly suitable for primary pro cessing, i.e. shortly before or during slaughtering.