Not much.

"You can reduce the number, but you’re not gonna get zero," said Dr. Ted Labuza, of the University of Minnesota.

Dr. Francisco Diez-Gonzalez, a University of Minnesota associate professor who has studied the impact of various washing techniques on produce said,

"At the consumer level, washing from the point of view of numbers, may reduce risk to 10 percent of the original risk. That’s been fairly consistent. But it’s definitely not solving the problem … If you happen to be lucky and the cells of the pathogen are not going to be attached to the surface, you may get lucky. If the cells have formed some structure and are strongly attached to the surface, you may not.”

Washing with water and some scrubbing motion applies friction, which has been shown to dramatically reduce the number of bacteria on a fruit or vegetable — from 100 percent risk to 10 percent risk, for example. But when the original numbers are in the trillions, that 10 percent risk can still be significant.

Running water on a fruit can reduce the risk to 15 percent. Scrubbing gets you to 10 percent, and using a mix of 3 parts water, 1 part vinegar can reduce the risk to 1 or 2 perecent.

So, it’s doing something, but it may not be enough.