E. coli of any sort is indicative of fecal contamination.

69% of the American spinach crop is grown in California. The

crisis resulted in a recall of spinach from Earthbound Farms

E. coli O157:H7, is a recent phenomenon.

Starting a few decades ago, Americans outsmarted Mother Nature. We switched our cows' diets from grass and hay to grain.

The new diet changed the acidity in cows' digestive tracts and the close living quarters led to a lot of cows and a lot of poop living side by side. That's when the new strain of E. coli, O157:H7, came on the scene. When cows eat grass, the acidity in their digestive tracts usually kills the bacteria, but grain fed cows' tummies do not.

So the mere fact that E. coli O157:H7 got into the water at all is a result of our need for cheap feedlot beef

In the past few years, spinach producers have stepped up food safety precautions. Farm workers wear rubber gloves and hairnets, for example, and dogs are no longer allowed into the fields.