Occurrence of C15-C45 mineral paraffins in olives and olive oils.

Different classes of olive oils and other olive samples (olives, olive paste and olive pomace) collected during their production were analysed for mineral paraffins in the range of C(15)-C(45). None of the 22 extra virgin olive oils contained mineral paraffins above the detection limit of 1 mg kg(-1). Also, lampante virgin olive oil from the olive mill showed no detectable amounts, but olive oil from the market contained 6-30 mg kg(-1). This contamination cannot be attributed to the refining step, which, on the contrary, partially removes the more volatile hydrocarbons, but could result from transport. Olive-pomace oils obtained by second centrifugation contained 16-145 mg kg(-1) mineral paraffins, presumably because of contamination during storage of the pomace. All olive-pomace oils from solvent extraction contained more than 100 mg kg(-1) mineral paraffins, also mainly from storage. Deposition of particulate matter from the air, vehicle exhaust emissions and direct contamination from the bulldozers used to move the pomace were identified as potential sources.

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 contaminated with mineral oil material originating from gas oils (C18-C35) or synthetic oils (poly-alpha olefins, C25 to beyond C45). An important cause is assumed to be the discharge of waste oils, such as motor oil and hydraulic oils. Mineral oil material was analysed by on-line LC-GC-FID directly in the fat or in a raw extract from animal feed or foodstuffs. In Switzerland in summer/autumn 1999 concentrations in oils and fats for feed production were often found to be between 100 and 1000 mg/kg. In the feeds, the average concentration 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 average concentration determined in summer 1999 was 25 mg/kg, with a maximum of 150 mg/kg, although in samples from December 1999, contamination was substantially 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).