PCDD/Fs and DL-PCBs in feeding fats obtained as co-products or by-products derived from the food chain

Abstract

Among the tasks included in the “Quality and safety of feeding fats obtained from co-products or by-products of the food chain” Project, supported by the European Union and included in the 6th Framework Program, a number of fats and oils collected as co- or by-products from the food chain were selected for the determination of polychlorinated dibenzo- p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and ‘ dioxin-like’ polychlorinated biphenyls (DL-PCBs). In the majority of the cases these samples are currently employed as feed ingredients. Nevertheless, additional fats, which are forbidden for feedstuff purposes were also considered in this study. In general terms, fats and oils were classified taking into account their nature and the processes applied to obtain these co- or by-products. PCDD/F and DL-PCB levels were evaluated in a first group of samples composed of fish oils, animal fats and lecithins. As expected, fats and oils with an animal origin presented higher concentrations, expressed in pg WHO-TEQ/g, compared to the levels found in vegetable samples like lecithins. The category of fish oils had the highest values for both PCDD/Fs and the sum of PCDD/Fs and DL-PCBs, with some samples showing levels above the maximum established at the present legislation related to the presence of PCDD/Fs and DL-PCBs in animal feed [Commission Directive 2006/13/EC of 3 February 2006 amending Annexes I and II to Directive 2002/32/EC of the European Parliament and of the Council on undesirable substances in animal feed as regards dioxins and dioxin-like PCBs. Official Journal of the European Communities L32, 44–53]. In a second group, fats and oils with a more complex composition obtained from different transformation processes or even mixtures of fats were considered; thus, acid oils from chemical refining, acid oils from physical refining, recycled cooking oils, oils extracted from exhausted bleaching earths, hydrogenated by-products, fatty acids calcium soaps and miscellaneous fats were analyzed. The data revealed a significant variability in PCDD/F and DL-PCB levels, expressed in pg WHO-TEQ/g, in these products. It has to be pointed out that the analyses of fats and oils belonging to these categories of products were sometimes difficult due to the complexity of the samples. In terms of legislation most of these samples cannot be easily included into one of the specific categories of substances intended for feedstuff purposes that are regulated in Commission Directive 2006/13/EC.