Levels and risk assessment of chemical contaminants in byproducts for animal feed in Denmark

Abstract

With aim to provide information on chemical contaminants in byproducts in animal feed, the data from an official control by the Danish Plant Directorate during 1998–2009, were reviewed and several samples of citrus pulp and dried distillers grains with solubles (DDGS) were additionally collected for analysis and risk assessment. The levels of contaminants in the samples from the official control were below maximum limits from EU regulations with only a few exceptions in the following groups; dioxins and dioxin-like polychlorobiphenyls (PCBs) in fish-containing byproducts and dioxins in vegetable and animal fat, hydrogen cyanide in linseed, and cadmium in sunflowers. The levels of pesticides and mycotoxins in the additionally collected samples were below maximum limits. Enniatin B (ENN B) was present in all DDGS samples. The hypothetical cases of carry-over of contamination from these byproducts were designed assuming total absorption and accumulation of the ingested contaminant in meat and milk and high exposure (a byproduct formed 15–20% of the feed ration depending on the species). The risk assessment was refined based on literature data on metabolism in relevant animal species. Risk assessment of contaminants in byproducts is generally based on a worst-case approach, as data on carry-over of a contaminant are sparse. This may lead to erroneous estimation of health hazards. The presence of ENN B in all samples of DDGS indicates that potential impact of this emerging mycotoxin on feed and food safety deserves attention. A challenge for the future is to fill up gaps in toxicological databases and improve models for carry-over of contaminants.

Keywords:

• Contaminants
• byproducts
• animal feed
• risk assessment; OTA
• ochratoxin A
• DON
• deoxynivalenol
• ENN B
• Enniatin B
• citrus pulp
• DDGS
• Dried Distillers Grains with Solubles

Acknowledgments

The authors wish to thank John Christian Larsen, DTU for constructive discussions and support during realization of the project. Jens Møller (Knowledge Centre for Agriculture) and Jesper Pagh (DLG-group) are acknowledged for providing information on the uses of byproducts as feed. Knud Erik Back Knudsen, Mogens Vestergaard, Henry Jørgensen and Martin Riis Weisbjerg all from University of Aarhus AU, are acknowledged for defining feed rations and inclusion rates of byproducts. The authors thank the food industry for kindly providing samples of citrus pulp and DDGS.

Additional information

Funding

The research project was funded by the Danish energy taxes from the agriculture (CO2 tax), funds administered by the Danish Ministry for Food Agriculture and Fisheries.