Lower instance of E. Coli

E. Coli is a serious health threat.  As a matter of fact, you are 1,000 times more likely to die of E. Coli than mad cow disease.  Grassfed animals have far fewer E. Coli than grain fed animals (20,000 cells/g. vs. 6,300,000 cells/g.)  Therefore you are far less likely to become infected with the bacteria when you eat grassfed beef.  Also, the few bacteria they do have are not likely to survive the natural acidity of our digestive tract.  This is because they have not become acid-resistant like the E. coli found in grainfed beef.  Feeding grain to cattle, even a small amount, makes their digestive tracts abnormally acidic.  The E. coli in their system becomes acclimated to this environment and therefore unaffected by our body's natural defense system.

E. coli contamination takes place in the slaughterhouse when manure from an animal comes in contact with meat. The less manure on an animal when it enters the slaughter house, the less likely the meat will become contaminated.

It is difficult to remove all the fecal contamination from feedlot cattle because they stand all day long in dirt and manure. In a recent article in the magazine Meat Marketing and Technology, the associate editor stated that pasture-raised animals were much easier to clean "because they come from small herds raised in relatively clean pastures." Most U.S. cattle, he said, "are raised in far larger numbers in congested and typically less sanitary feed lots.

The Main Source of Contamination is the Slaugherhouse

Contamination from E. Coli occurs when cattle are processed at the slaughterhouse and the manure from that cattle comes in contact with the meat.  Feedlot cattle are covered with their own manure, because they are continually exposed to it in the feedlot.  It is almost impossible to remove all the fecal contamination from feedlot cattle.

In contrast, contamination from a pastured animal is far less likely.  Cattle raised in a  clean pasture will undoubtedly have smaller amounts of manure on the them.