There's no such thing anymore as just eating a steak. Was it grass fed? Did it have a hobby? Now, thanks to a group of Irish chemists, you'll never have to worry again about your Porterhouse's diet. Just your own.
Turns out that the proportion of stable isotopes of oxygen, nitrogen, hydrogen and sulfur found in the posthumous muscle tissue and tail hair of cattle can tell you a lot about what animals ate before landing on your dinner plate—and in some cases, where they ate it:
Certain diets yielded a distinctive signature, the researchers report in the Journal of Agricultural and Food Chemistry. They couldn't tell between animals that ate from a pasture and those that ate grass silage, but there were clear differences between animals that ate pasture grass and those that ate concentrated food products. Using hair and tail samples, they could even follow changes in an animal's diet over the course of its lifetime.