By Sachi Wickramasinghe
University of British Columbia

A starch-based fruit wash eliminates pesticides and extends freshness with a protective edible coating, showing promise for reducing waste and improving food safety.

Researchers at the University of British Columbia have created a natural, biodegradable fruit wash that removes up to 96 percent of pesticide residue while also slowing browning and moisture loss.

The innovation could lead to safer apples, grapes, and other fruits that stay fresh and crisp for several extra days. With food prices rising and nearly half of fresh produce wasted globally each year, a solution that reduces both pesticide exposure and spoilage could have significant benefits. The findings were published in ACS Nano.

Our goal was to create a simple, safe, and affordable wash that improves both food safety and food quality. People shouldn’t have to choose between eating fresh produce and worrying about what’s on it.

Motivation and Pesticide Concerns

Although pesticide use on fruits and vegetables is strictly regulated, small amounts often remain. For people who frequently eat large quantities of the same produce, such as children consuming bowls of berries, exposure can sometimes exceed recommended levels.

The wash is made from tiny starch-based particles, the same type of carbohydrate found in organic corn and potatoes, combined with trace amounts of iron and tannic acid. Tannic acid is a natural plant compound responsible for the dry color in tea. When paired with iron, it forms a sticky, sponge-like structure that binds to pesticides and pulls them from the fruit’s surface.

To evaluate its effectiveness, researchers applied three commonly used pesticides to apples at real-world concentrations of about 10 milligrams per liter (about 0.01 grams per quart).

High Pesticide Removal Performance

In apple tests, the wash removed between 86 and 96 percent of pesticide residues. By comparison, rinsing with tap water, baking soda, or plain starch typically eliminates aprox half.

After cleaning, the fruit is dipped again to create a thin, edible, biodegradable coating. Fresh-cut apples treated this way browned more slowly and retained more moisture over two days in the refrigerator. Whole grapes remained firm for up to 15 days at room temperature, while untreated grapes showed clear signs of shriveling.