E. coli outbreak raises questions about bagged salad

The Atlanta Journal-Constitution reports that a national alert to throw away salad mixes linked to an E. coli outbreak in the Midwest has raised questions about the safety of pre-washed salads.
Packaged spinach and lettuce mixes have been tied to several E. coli 0157:H7 outbreaks in recent years. Earlier this week, the FDA issued a national warning against eating three kinds of Dole salad blends that have been linked to a September outbreak. At least 13 people have been sickened in Minnesota and Wisconsin; four were hospitalized and released.
Other packaged salads have been linked in the past few years to outbreaks in restaurants, a nursing home and at a cheerleading camp.
The U.S. Food and Drug Administration as well as the produce industry say that pre-washed salads can be eaten without further washing. Some food safety experts urge consumers to wash anyway, but caution that it may not eliminate bacteria.
Bacteria that cause food-borne illness can be destroyed by cooking, but most salads are served raw. That makes the cleanliness of the product even more important.
Researchers at the Center for Food Safety in Griffin have performed experiments with lettuce contaminated with high doses of salmonella or E. coli bacteria, washing it with chlorinated water. It removed only a small amount of the bacteria.
The FDA and the Minnesota Department of Health are looking for the source of the outbreak.