Confirmation of the Dietary Background of Beef from its Stable Isotope Signature

Abstract

Consumers are increasingly demanding information on the authenticity and source of the food they purchase. Molecular DNA-based technology allows animal identification, but without certification or a “paper-trail” but does not provide information about feed history or the production system under which the animal was reared. The stable isotopes of chemical elements (e.g.13C/12C, 15N/14N) are naturally present in animal tissue and reflect the isotopic composition of the diet. The overall aim of this project was to determine the feasibility of using the stable isotopic composition as an intrinsic, biochemical marker to gain information about feed components used in the production of beef. Factors likely to affect the isotopic signature such as source of tissue, duration of feeding and production systems were examined. It is expected that this highly innovative and original technique will permit the identification of country of origin and dietary history of beef and so greatly assist efforts to market Irish beef, particularly in lucrative European markets. Sequential sampling and stable isotope analysis of bovine tail hair and hoof revealed that the two tissues can provide a detailed and continuous record of animal dietary history. Because hair can be sampled repeatedly and noninvasively, we anticipate that this approach will also prove useful for the investigation of short-term wildlife movements and changes in dietary preferences.