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August 18, 2009

Helpful Hints from joeeze: Should bagged prewashed lettuce be washed again before eating?


I can't speak for you but this question sometimes keeps me up at night.

Cook's Illustrated, in its latest (September & October 2009) issue, addresses the question as only they can and do.


To kill off bacteria, packagers of prewashed organic and conventional lettuce first rinse the greens with water and then typically spray them with a diluted chlorine solution. Despite these measures, E. coli outbreaks associated with prewashed bagged lettuce and spinach have been reported. Nonetheless, the U.S. Food and Drug Administration and many other food safety experts take the position that prewashed lettuce can be used without further washing. Here's why: prewashed produce is likely to have fewer bacteria (or none at all) then your kitchen sink or counter, and washing the greens may actually introduce bacteria. (We found this to be the case when we took swabs from prewashed lettuce straight from the bag and swabs from lettuce we "rewashed" in the test kitchen. The rewashed lettuce grew bacteria in a petri dish, while the untouched prewashed greens did not.) Furthermore, according to Trevor Suslow, a microbiologist specializing in food safety research at the University of California, Davis, if pathogens such as E. coli or Salmonella are actually present, rewashing removes very few cells and may actually spread contamination.

The Bottom Line: We agree with the experts who say additional washing of ready-to-eat greens is not likely to enhance safety.


Trust me on this: your kitchen isn't anywhere near as clean as that at Cook's Illustrated.

When I think of some of the places where I lived and kept and prepared my food back when I was in college — specifically, the Beta house on Gayley Avenue, one summer at UCLA — I'm amazed I'm still alive.

August 18, 2009 at 10:01 AM | Permalink


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What doesn't kill you, makes you stronger

Posted by: JY | Aug 18, 2009 11:08:04 PM

If we only knew (or could see bacteria) in our food area, or how fast food and better restaurant food is handled, we would be in a constant state of regurgitation!

Posted by: Joe Peach | Aug 18, 2009 4:56:50 PM

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