How to Effectively Clean Fruits and Vegetables for Safety and Health

It's a healthy habit most do right before snacking on some fruit or cooking vegetables. We do it without thinking, often taught by our parents.

But there's some science to keep in mind. How should we clean produce? And what common mistakes do people make?

From farmland to store shelves and soon your kitchen, produce is a healthy choice that sometimes needs a healthy rinse.

"If it's blueberries, I put them in a strainer and run water over them," said one shopper at Kowalski's in Minneapolis.

"Maybe for things like potatoes, I'll wash them and wash the skin with a brush," added another shopper.

Pesticides were one reason they try to clean produce.

"Some items aren't being thoroughly washed by farmers before they go to sale," said Amy Johnston, a food safety expert with the University of Minnesota Extension.

Why should we clean our produce? 

Dirt is the first reason that comes to mind, but Johnston said certain bacteria and pesticides could also be on fruits and vegetables. Many pesticides farmers use are water-soluble, meaning rinsing produce with water can get rid of the chemicals.

How should we clean our produce? 

It depends on the type. For food with thin skin, like peppers and tomatoes, Johnston said to use cold running water and your hands.

"Hot water can actually cause something called thermal shock," she said. 

Produce with thin skin is most susceptible to thermal shock. Because the skin is porous, hot water can cause elements on the food's surface (bacteria) to permeate the skin and seep into the food.

For firm foods with thick skin, like carrots, Johnston says to keep the water cool but add a scrub brush for deeper cleaning. 

"That scrub brush is going to really help us get into those nooks and crannies that we might not be able to rinse away," she said.

Also, make sure the brush you use is just for produce and not for dishes.

Salad spinners work well at cleaning leafy greens, berries and herbs. 

Can you use dish soap to clean produce? 

You should not use dish soap or any chemical cleaner. There's the risk of it consuming it, and Johnston said they haven't been shown to actually clean the food in the way users are hoping.

There are, however, several products marketed for cleaning fruits and veggies. They come in the form of sprays, powder mixtures or even specialized vinegar with the goal of cleaning off pesticides or bacteria beyond using just water.

"There's not much research that shows that household solutions are more effective," said Johnston. "(They're) not going to do any harm, so if it gives you that extra layer of comfort to use it, by all means, just make sure that it's safe for food."

What common mistakes do people make when they're cleaning produce? 

"First one is not starting with a clean and sanitized kitchen sink," Johnston said.

A sink, including the faucet components, as well as the workspace, must be clean and sanitized.

Another mistake is using a kitchen towel for drying. Doing so could add contaminants to the food that was just cleaned. Instead, use a paper towel, salad spinner or just air dry.

Hot water is good for cleaning your hands, but some people apply that rule to produce. Stick with a cold water rinse to ensure thermal shock doesn't occur.

Another tip is to wait to clean produce until right before you eat or cook with it. Doing so can make it ripen faster, even if it's put in the fridge.

Some people might think they don't need to clean fruits or veggies in which you don't eat the skin, like watermelon. Johnston, however, said that kind of produce still needs to be cleaned. For example, a knife cutting through a watermelon that wasn't cleaned will drag bacteria or pesticides with it into the fleshy part of the fruit.

For more advice from Johnston and the UMN Extension, click here.