How can I wash all the pesticides off my food?

May 19, 2014 by Matt Shipman, North Carolina State University
Showy colors, bizarre shapes, or surprising textures of exotic lettuces may brighten salads of the future. In California's Salinas Valley, where much of America's lettuce is produced, ARS researcher Edward Ryder and colleague William Waycott, scrutinize an exceptional array of unique lettuces. Credit: Patrick Tregenza.

What is the best way to wash all the pesticides off your food? The bad news: you can't. The good news: you shouldn't worry about it too much.

If there is any on the outside of your food, your best bet for removing as much as possible is to wash it vigorously under running water. (Don't use soap or you could actually be adding chemicals to the produce.)

But you won't get it all, and some of the residual pesticide is probably inside the food anyway. Here's the thing though: you don't need to freak out about this.

If farmers are using a pesticide in accordance with that pesticide's label requirements (which is what they are legally required to do) then there is something called a "pre-harvest interval."

"A pre-harvest interval is the length of time after a pesticide is applied that a farmer has to wait before harvesting the crop – and that interval is specified on each pesticide's label," says Chris Gunter, a researcher at NC State who focuses on vegetable agriculture.

The idea is that the pesticide is broken down, washed off or evaporated by sunlight, water or other environmental factors during the interval period. This means that any residual pesticide on (or in) the plant is within the tolerance levels established by EPA to protect human health. (If you're curious, here's how EPA assesses health risks from pesticides.)

"With improved technology and methodology, we can now detect extremely minute levels of pesticides," Gunter says. "But being able to detect a pesticide doesn't mean that it's a public health problem."

Another reason that you can't wash off every trace of a pesticide is that some pesticides are designed to be incorporated into the plant itself, either absorbed through the plant's "skin" or taken up through its roots. But those pesticides are also covered by the required pre-harvest interval requirements.

"As long as farmers are following the label, EPA has verified that the used don't pose a meaningful risk to consumers," Gunter says.

Explore further: Eating organic food significantly lowers pesticide exposure

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User comments : 5

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5 / 5 (3) May 19, 2014
If the crop is a GMO designed to produce a pesticide in every cell (i.e. the Bt toxin), you cannot wash it off. You are forced to eat it, especially if, as Monsanto has lobbied, you are not told that the toxin is in the food by virtue of it being GMO. This is the future that Monsanto has for us - forcing us to eat toxins at our expense and their profit.
5 / 5 (2) May 19, 2014
This means that any residual pesticide on (or in) the plant is within the tolerance levels established by EPA to protect human health.

And the establishment of these guidelines (i.e. what constitutes a health risk and what doesn't) is the product of lawmakers/politicians who get lobbied by ... ?

... you fill in the blank
not rated yet May 19, 2014
i thought monsanto OWNED the EPA?
not rated yet May 20, 2014
First, the EPA has an atrocious track record.

Second, "pre-harvest interval" may not make much difference for imported food. Border service agents can, at their discretion, spray food entering the country (at least in Canada).
May 20, 2014
This comment has been removed by a moderator.
not rated yet May 20, 2014
Second, "pre-harvest interval" may not make much difference for imported food.

It's also a bit dependent on the weather in that period. If there's a dry spell then nothing will be washed off.

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