There's a 25% chance your supermarket ground beef contains antibiotic-resistant fatal bacteria

[frazzled]

50. Organic grass-fed beef is just as susceptible to E-coli bacteria

The comparative health benefits of grass-fed beef are well documented. Scores of studies indicate that it's higher in omega 3s and lower in saturated fat. But when it comes to E. coli O157:H7, the advantages of grass-fed beef are not so clear. In fact, exploring the connection between grass-fed beef and these dangerous bacteria offers a disturbing lesson in how culinary wisdom becomes foodie dogma and how foodie dogma can turn into a recipe for disaster.
Could grass-fed beef ever be afflicted with the sort of E. coli O157:H7 outbreak that led to the December recall? Not according to the conventional wisdom among culinary tastemakers. This idea rose to the top of the journalistic food chain in the fall of 2006, when food activist Nina Planck wrote about the bacteria strain on the op-ed page of the New York Times. ...

Unfortunately, the scientific evidence tells a very different story. Planck's assertion seems to be based on a 1998 report published in the journal Science. In this study, the authors fed three cows a variety of diets in order to ascertain how feed type influenced intestinal acidity in cows and, in turn, how intestinal acidity influenced the concentration of acid-resistant strains of E. coli. They hypothesized that these strains would be especially dangerous to humans, since they could survive the low-pH environment of the human stomach. It turned out that grain-fed cattle did indeed have a much more acidic stomach than those fed grass or hay. And sure enough, they had a million times more acid-resistant E. coli in their colons. ...

But between 2000 and 2006, scientists began to take a closer look at the effect of diet on E. coli O157:H7 specifically. A different set of findings emerged to indicate that this particular strain did not, in fact, behave like other strains of E. coli found in cattle guts. Most importantly (in terms of consumer safety), scientists showed in a half-dozen studies that grass-fed cows do become colonized with E. coli O157:H7 at rates nearly the same as grain-fed cattle. An Australian study actually found a higher prevalence of O157:H7 in the feces of grass-fed rather than grain-fed cows. The effect postulated (and widely publicized) in the 1998 Science report—that grain-fed, acidic intestines induced the colonization of acid-resistant E. coli—did not apply to the very strain of bacteria that was triggering all the recalls.

http://www.slate.com/articles/health_and_science/green_room/2010/01/beware_the_myth_of_grassfed_beef.html

And, indeed, there have been a number of recalls of organic grass-fed beef (google it). Same with vegetables ... organic spinach can be bad, too.