what to wash lettuce in

Asked September 13, 2013, 5:34 AM EDT

I have read stories in the news about recalls during the years regarding e-coli and lister bacteria in bagged salad mixes. What can I wash my bagged salad mix and lettuce in general in to ensure these or any other potential harmful bacterias are killed? I just plain water enough?

Stafford County Virginia food safety lettuce horticulture

1 Response

Hi Andrea. Thanks for writing to us. You ask a good question and I understand your concern. Lettuce, especially, is often the culprit of foodborne illnesses. There are a two main reasons for this -

1. When lettuce is contaminated anywhere along the food chain (farm to grocery to kitchen to your mouth) the contamination is often located inside the lettuce leaf. The reason for this is that leaves contain stomates (which is how the plant breathes - and brings in CO2 for photsynthesis) and if the water used to irrigate the lettuce is contaminated it goes right down into those stomates. And once that happens, the pathogens are present inside the leaf and can't be removed.

2. Lettuce is classified as a potentially hazardous food - and, as such, is handled in specific ways. For example, once cut, it must remain refrigerated and be consumed relatively quickly. Think of shredded lettuce mixes. The reason for this is that you have all these surface areas on the lettuce that's been shredded and if the knife used to cut the lettuce is contaminated - all those leaf surface areas now also have that contaminate on them and a good, moist surface to grow on.

The good news - On the farm end, a lot is being down to make sure farms (small and large) are following Good Agricultural Practices. GAPs are a series of management practices implemented on the farm that minimizes the risk of contamination into the food supply. It is important to note here that re: food safety it doesn't matter if the farm is organic/conventional/small/large. Despite what you may hear, a small farm down the street can be just as likely to be the source of contaminated produce as a large farm out in California. What matters is that the farm is adhering to food safety practices. I realize you probably cannot speak directly to the growers who are supplying your local grocery store with product as to how they are managing their food safety risks, but remember that farms have a lot to lose if they are implicated in a food borne illness outbreak - and do their best to make sure their product is safe. If you are skeptical in purchasing from a grocery store, I would encourage you to talk with our local farmers at one of the local farmers markets - and ask them questions about what they're doing to ensure the safety of their produce.

For any lettuce you purchase, I would encourage you to make sure it has been handled appropriately. For example, never purchase shredded lettuce that is being sold outside of a refrigerated cooler. (I've actually seen this at a grocery store - but thankfully not locally!) Lettuce that hasn't been shredded or cut does not have that additional source of potential contamination to worry about - and because of this, I always purchase spring mixes or head lettuce (romaine, green leaf, red leaf, etc). I don't purchase pre-shredded lettuce.

One additional note from Dr. Renee Boyer, a Food Safety specialist at Virginia Tech, in regards to washing the lettuce. She states, "The recommendation is to use just water, but even then the recommendation for bagged triple washed products is to NOT rewash them because of the higher chance of cross contamination from something else in the kitchen."

If you have any questions or if I can clarify anything, please drop me another line. Thanks, Cathy