Polycyclic aromatic hydrocarbons (PAH) belong to a large chemical family comprising many different compounds with important biological activity in mutagenic and carcinogenic processes. PAH have been detected in both raw and processed foods. The presence of PAH in non-processed foods is associated with environmental pollution from both human and industrial activities, whereas contamination of processed foods can be caused by certain preservation and processing procedures. Both toxicological and epidemiological studies have shown a relation between such compounds and tumor development. The data indicate that PAH must undergo a biotransformation process that causes the formation of biologically active metabolites. In this process, the presence of an enzyme complex that is induced by different xenobiotics is implied, making the toxicity of such compounds hard to predict. As setting a threshold limit below which toxicity could be considered negligible is difficult, the presence of PAH in foodstuffs should be reduced to as low as possible by controlling environmental contamination and all procedures that could cause PAH contamination during food processing, preserving, and packaging.

The presence of polycyclic aromatic hydrocarbons (PAH) in smoked cheeses of different origin was studied. The samples were subjected to an initial extraction of fat and an alkaline treatment, extracted with cyclohexane, cleaned up by means of solid-phase extraction tubes, and analyzed by gas chromatography/mass spectrometry (GC/MS) operating in selective ion-monitoring mode (SIM). The results revealed the presence of numerous polycyclic aromatic hydrocarbons in the exterior zone of the samples, some of them with methyl groups. In all cases, the concentrations of compounds of low molecular weight were much higher than those of high molecular weight. Polycyclic aromatic hydrocarbons with varying degrees of carcinogenicity were identified, including benzo(a)pyrene in concentrations, which, although they did not exceed the limit established for this compound in the rind of ripened cheeses, do exceed the limit of 0.03 microg/kg fixed for other foods smoked with smoke flavorings. Significant differences in the number and concentration of PAH in smoked cheese also were observed from rind to interior, the rind being the most contaminated zone.