Interesting article in Slate by James McWilliams on the supposed health benefits of grass fed beef. Yes, says McWilliams, grass fed beef has higher levels of omega 3s and lower levels of saturated fat. But, no, says McWilliams, there is no evidence that grass fed beef is free from the E. coli bacteria that has been causing recalls recently of ground beef (O157:H7 variety). 

McWilliams traces the widespread belief that grass fed beef is free from O157:H7 to an op ed piece in the New York Times by food activist Nina Planck. Planck wrote that O157:H7 was ‘not found in the intestinal tracts of cattle raised on their natural diet of grass, hay, and other fibrous forage.”  This assertion was apparently based on a 1998 report in Science that McWilliams says is now out of date. After that initial report, subsequent studies have found that O157:H7 is found in grass fed cattle.

“The point in dredging up these studies—ones the media never covered—is not to play gotcha with advocates of grass fed beef,” McWilliams writes. “(As mentioned above, grass fed beef may be healthier than conventional beef over all, and kinder to the animals.) Instead, it’s a warning that advocacy for a trendy food choice might result in a public health hazard.” McWilliams is the author of Just Food: Where Locavores Get It Wrong and How We can Truly Eat Responsibly