Contamination of animal feed and food from animal origin with mineral oil hydrocarbons

Oils and fats used for the production of animal feed can become contaminate d with mineral oil material originating from gas oils (C18-C35) or syntheti c oils (poly-alpha olefins, C-25 to beyond C-45). An important cause is ass umed to be the discharge of waste oils, such as motor oil and hydraulic oil s. Mineral oil material was analysed by on-line LC-GC-FID directly in the f at or in a raw extract from animal feed or foodstuffs. In Switzerland in su mmer/autumn 1999 concentrations in oils and fats for feed production were o ften found to be between 100 and 1000 mg/kg. In the feeds, the average conc entration was around 100 mg/kg with values ranging up to a maximum of 1000 mg/kg; few samples were free of contamination. In animal body fat, the aver age concentration determined in summer 1999 was 25 mg/kg, with a maximum of 150 mg/kg, although in samples from December 1999, contamination was subst antially lower. In the fat phase of eggs, the average concentration was 30 mg/kg, with a maximum of 80 mg/kg. Paraffin oil is used for feed production , which may account for part of the contamination problem (e.g. eggs).