Pre-cut romaine lettuce may be the cause of an E. coli outbreak that has sickened at least 23 people in recent months.  The strain of E. coli at issue, which is typically found in the feces of cattle and wild animals, has raised questions about the processing practices for pre-cut produce. Pre-cut salad mix is a popular item, outselling whole heads of lettuce by more than 2 to 1 between January 2009 and January 2010.

The romaine lettuce linked to the most recent outbreak was precut and sold to food service companies for use in restaurants and salad bars.  Some of the victims included college students in four states who are believed to have eaten contaminated lettuce in their school dining halls.  At least a dozen victims were hospitalized, three of them with life-threatening kidney failure.

Microbiologists and public health experts, citing a number of multi-state outbreaks involving pre-cut produce during the past five years, are voicing concerns that pre-cut produce may be riskier than vegetables sold whole.  Some question the common practice of removing the outer leaves and cores from heads of lettuce in the field with cutting utensils that can be contaminated by soil, in turn spreading contamination to the harvested crop.  It is very difficult to remove bacteria from the leaf once infected.  E. coli can be a soil contaminant, particularly in farming areas close to cattle farms.

Another concern is cross-contamination of lettuce from different areas.  Pre-cut lettuce may be harvested from different farms, but batched and mixed together, raising the risk of cross-contamination of a high volume of produce.

In response to these concerns, the Food and Drug Administration (FDA) is developing the first set of regulations for fresh produce, scheduled for publication in early 2011.  A bill is also pending in Congress which would give the FDA more authority to regulate produce and other food items.

For the full story, go to the Washington Post.