Does Washing Produce Remove Pesticides and Bacteria?

Washing produce is good practice. But understanding what it actually does — and doesn’t do — helps you make smarter decisions about which items to wash, how to wash them, and when washing isn’t enough.

What Cold Water Washing Actually Removes

USDA research consistently shows that rinsing produce under cold running water removes 75-80% of surface pesticide residues. The friction of water moving across the surface, combined with rubbing with your hands, physically dislodges and carries away pesticide films that sit on the outside of the produce.

That number is good but not perfect. Some pesticides penetrate the outer cells of produce through normal uptake. These systemic residues aren’t accessible to surface washing. If removing all pesticide residue is the goal, peeling removes substantially more than washing for thick-skinned items like apples, cucumbers, and potatoes. For items like grapes or strawberries, peeling isn’t practical — washing is what you’ve got.

For bacteria, the picture is similar. Running water with physical friction removes a significant portion of surface pathogens. Studies on produce washing consistently find 1-2 log reductions (90-99% reduction) in surface bacterial counts with thorough water washing. That’s meaningful. It’s not sterilization, but it substantially reduces the bacterial load you’re eating.

Commercial Produce Washes Don’t Add Anything

Produce washes are sold with the implication that they clean more effectively than plain water. FDA testing doesn’t support that claim.

Multiple studies, including research published in the Journal of Food Protection by Annous and colleagues (2004), found no significant difference in bacterial reduction between plain water and commercial produce wash solutions. The physical action of rinsing and rubbing is what removes surface contamination. The chemical composition of the rinse water matters very little.

This makes mechanical sense. Bacteria on produce surfaces aren’t chemically bonded to the surface. They’re adhered loosely, and mechanical action — water pressure and rubbing — dislodges them. Chlorinated sanitizers do outperform plain water, but at concentrations that would leave a chemical taste and residue on food. Produce washes use compounds at concentrations too low to have a sanitizing effect.

Soap is a different story, and not in a good way. Dish soap and hand soap absorb into the porous surfaces of produce. They’re not designed to be edible, and you can’t rinse them out completely once they’ve penetrated the surface cells. FDA explicitly recommends against soap, detergent, or bleach on produce. Plain water is the right tool.

The Internal Contamination Problem

The 2006 spinach E. coli outbreak is the most important case study in understanding what washing can and can’t do.

The outbreak caused 199 illnesses, 31 cases of hemolytic uremic syndrome (a kidney complication), and 3 deaths across 26 states. Investigators traced the contamination to a California spinach farm where irrigation water had been contaminated by feral pigs near cattle pastures. The E. coli O157:H7 was in the irrigation water the plants absorbed while growing.

Washing the spinach wouldn’t have prevented these illnesses. The bacteria were inside the leaf tissue, not just on the surface. This is internal contamination, and no amount of surface washing addresses it.

This distinction matters because it changes how you think about produce risk. Most contamination is on the surface, deposited by handling, soil contact, or aerosols. Washing handles that. A smaller category of contamination is internal, originating from contaminated water or soil absorbed by the plant. Washing doesn’t handle that. The only way to address internal contamination is heat — cooking the produce to temperatures that kill pathogens throughout the tissue.

This is why leafy greens eaten raw carry more inherent risk than produce that gets cooked. Cooking tomatoes kills surface and internal pathogens. Serving spinach raw doesn’t.

Practical Washing Protocol

Rinse all fresh produce under cold running water before eating or cutting, including items you’ll peel. The reason to wash before peeling: your knife or peeler can carry surface contamination from the outside of a melon or avocado directly into the flesh as you cut. Washing first prevents that.

Use your hands to rub the surface of firm produce like apples, peppers, and cucumbers as you rinse. For firm vegetables like carrots, potatoes, or squash, a clean produce brush adds more friction and removes more residue.

Don’t soak produce in standing water. Soaking pools bacteria from all the produce into a single bath and can actually spread contamination from one item to others. Running water is more effective than standing water.

For packaged greens labeled “ready to eat” or “triple washed,” rewashing in tap water can introduce contamination rather than remove it. FDA says you can use them as-is if the label says they’re ready to eat.

References appear at the bottom of this page.