Thirty shrimp, marine fish, freshwater fish, and canned fish composite samples collected and prepared as part of the Canadian Total Diet Study were analysed for 39 different veterinary drug residues. The analyses were undertaken to obtain baseline data that could be used to estimate the dietary exposure of Canadians to these residues. The most frequently observed residue was AOZ (four out of 30 samples), the metabolite of furazolidone, at a range of 0.50 to 2.0 ng g(-1) wet weight. Other residues detected included enrofloxacin (three samples; 0.3-0.73 ng g(-1)), leucomalachite green (three samples; 0.73-1.2 ng g(-1)), oxolinic acid (two samples; 0.3-4.3 ng g(-1)), AMOZ (the metabolite of furaltadone; one sample; 0.40 ng g(-1)), chloramphenicol (one sample; 0.40 ng g(-1)), and SEM (the metabolite of nitrofurazone; one sample; 0.8 ng g(-1)). The results of this survey indicate that Canadians are exposed to low ng g-1 concentrations of some banned and unapproved veterinary drug residues via the consumption of certain fish and shrimp.

SUMMARYRainbow trout and specimens of pond mud were collected from three fish farms and examined for the presence of Clostridium botulinum. Two of the farms were constructed with concrete channels and one was mud-bottomed.Cl. botulinum was isolated only from the mud-bottomed farm (24 % of muds), and the isolates were all non-proteolytic type B. The implications of the presence of Cl. botulinum spores in the mud of fish farms is discussed.