Transfer of chemicals from feed to animal products: The use of transfer factors in risk assessment

Abstract

The human risk assessment of feed contaminants has often been hampered by a lack of knowledge concerning their behaviour when consumed by livestock. To gain a better understanding of the transfer of contaminants from animal feed to animal products, a meta-analysis of public literature was made. Data concerning feed contaminant concentrations, feeding periods, residue levels in animal products, and other parameters were gathered and recorded. For each case a ‘transfer factor’, which was defined as the ratio of the concentration of a chemical in an animal product to the concentration of the chemical in animal feed, was calculated. Scientifically founded transfer factors were calculated and analysed for groups of chemicals based on their contaminant classes or physicochemical properties. These database-derived transfer factors enable a more accurate risk assessment in the case of a feed contamination, and enable rapid risk management decision-making and/or intervention.

Keywords:

• Transfer factor
• carry-over
• contaminants
• residues
• risk assessment
• risk management

Acknowledgements

The authors wish to thank Ms Monique Rennen and Jos Bessems for a critical review of and for suggestions for the manuscript, and Ms Carina Rubingh for statistical analysis of the data.