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Excerpt from:
Science News Online
www.sciencenews.org
September 28, 1996
“It takes more than a tap water rinse to dislodge E. coli and many other microbial squatters. Though high temperatures kill them, cooking is hardly a viable answer for lettuce, sprouts, and tomatoes that go into your fresh salad. For these and other foods that are to be eaten raw, consider another solution …suggests Susan Sumner, a food scientist at Virginia Polytechnic Institute and State University, in Blacksburg.
While at the University of Nebraska (which she departed last month), Sumner worked out the recipe for just such a sanitizing combo.
First, she squirts a vegetable with 3 percent hydrogen peroxide, the same strength available at the drug store for gargling or disinfecting wounds. She follows this up with a mist of mild acetic acid (vinegar). In truth, she says, which solution is sprayed first doesn’t matter…She uses 2 regular spray bottles.
The solutions represent an adaptation of a chlorine-free disinfection scheme she had been working on for red meat, and which turned out to be effective for decontaminating carcasses. In the course of her more recent studies, Sumner found that vegetables not only tend to come from the garden or farm bearing far more germs than red meat does, but they also hold onto germs more tenaciously.
Overall, most germs that show up on produce come from the soil and are benign. However, worrying that more toxic germs spread by feces could show up in organic foods fertilized with manure, and realizing there have been reports of Shigella on cantaloupe and Salmonella on raw vegetables, Sumner decided to develop a bactericidal treatment for restaurants and other purveyors of salads.
In her tests, she deliberately contaminated clean fruits and vegetables with Salmonella, Shigella, or E. coli O157:H7 – all capable of inducing gut-wrenching gastroenteritis. On its own, the hydrogen peroxide was fairly effective against all three germs, she found. But the best results came from pairing the two mists. For instance, she told Science News Online, “If the acetic acid (vinegar) got rid of 100 organisms, the hydrogen peroxide would get rid of 10,000, and the two together would get rid of 100,000.”
What I really liked about this treatment,” she adds, “is that every [microbe] that drips off is killed.” So you’re not just transferring disease-causing contamination from your food to the sink, drain, or cutting board. Speaking of which, she notes that the paired sprays work well in sanitizing counters and other food preparation surfaces – including wood cutting boards.
As for taste, the peroxide didn’t leave any lingering flavors and the vinegar, when applied to the skins of tomatoes and peppers, proved hard to detect. While vinegar’s trace could be picked up on lettuce, even that isn’t necessarily a major drawback, Sumner notes, especially if it’s destined for a salad to be dressed with a vinaigrette.”
Peters, D., Sumner, et al. 1996. Control of pathogenic bacteria on fresh produce, a paper (abstract #168) presented in Seattle on July 2 at the 83rd annual meeting of International Association of Milk, Food and Environmental Sanitarians.
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Email to Susan sent 6/16/2008:
Dear Susan,
I read your article from Science News Online from September 28, 1996 regarding spraying raw produce with vinegar and 3% hydrogen peroxide and found it valuable info for use in the home. Seeing as this was published 10+ years ago, I was wondering if this is something you still recommend? Is there something that works better that can work easily in the home?
If you still recommend this procedure, can you mix H2O2 and vinegar together in one spray bottle and use it that way?
Susan’s response:
Gwenith,
Still a very good idea. We only tested the surface of different produce, but we are starting an experiment this summer using different surfaces.
You may mix the two (hydrogen peroxide and vinegar) together in one bottle, but it must be used immediately. The advantage to keeping the solution in separate bottles is that you can keep the solutions longer. Leave the solution on for at least 1 minute before rinsing thoroughly.
Susan
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Gwenith’s comments:
Vinegar has an indefinite shelf-life.
Hydrogen peroxide -- 3% and 6% food grade hydrogen peroxide are relatively safe (they will cause vomiting if swallowed; however, no long term side effects). 3% and 6% food grade hydrogen peroxide are heat stable; it will last several years (they will not degrade because of being exposed to heat). Keep it in the dark bottle for longer shelf-life.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhccB50CSyYkDtmnwiBmq77fYY675ENkDE0N-k2KNqggb0iQydhDgU3lQARqGBiohQp0aT_Igt7F5xI7k2nuNnFEuin1aOl6yeYoN-70SYTFhOqfo2ahR78vqrG7TmcGWcXl_3yh2AxUS6s/s280/Vinegar+%26+Hydrogen+Peroxide.jpg)
Don’t dip anything into the hydrogen peroxide. Screw a spray bottle head (after sanitized) onto the hydrogen peroxide bottle and use it that way. It fits!
Leave the solutions on for at least 1 minute. Please remember to rinse the vegetables thoroughly after spraying with the solution!
Gwenith
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