Because I'm not much of a cook, I end up making (and eating) many salads, mezze plates and sandwiches for lunches and dinners. And because I'm a two-decades-strong vegetarian, that means I consume large quantities of vegetables. I also love eating fruit — and always have — it's my go-to pre-workout snack, dessert and afternoon treat to tide me over to dinner (also sometimes breakfast too, if I'm too busy).
I buy my produce at Whole Foods, the farmers market from May to October (I live in New England and New York, with its limited growing season), and pull it from my own garden for much of the summer (mostly just greens, herbs and beans, which are wonderful in the way that they pretty much grow themselves). Wherever I get my produce from, I always wash my veggies and fruits well — though I will admit to sometimes eating food straight from the stalk in my own garden — but I'm surprised when I see that many people don't bother to even rinse their food at all before preparing it.
According to the FDA, "Harmful bacteria that may be in the soil or water where produce grows may come in contact with fruits and vegetables and contaminate them. Fresh produce may also become contaminated after it is harvested, such as during preparation or storage. Eating contaminated produce (or fruit and vegetable juices made from contaminated produce) can lead to foodborne illness, often called 'food poisoning.'"
So unless your produce or veggies say "pre-washed" or "ready-to-eat" you should most definitely be washing them. The FDA says you should rinse them under running water (and that's all you need), and you should scrub hard-skinned veggies/fruits like cucumbers or melons, but there are a couple of products that use very mild additions to water that I think do work to get produce a bit cleaner (all of which are edible and nontoxic).
iGozen is a spray cleaner that's simply a microfine powder made from crushed seashells; the powder is gentle enough to use on soft fruits and veggies, but still is abrasive enough to remove "dirt, toxins, pesticides and bacteria." I've been using this in my home for the past three months and I really like that it doesn't have an associated smell or taste of any kind, and that you can use it to clean counters, too. And because you refill a reusable spray bottle with a simple powder, there's no waste with iGozen because even the packets are recyclable.
I've also used Veggie Wash in the past and was happy with it, though I didn't love the wasteful spray container if comes in. But it is made with food-derived cleaning ingredients, so it's nontoxic.
You can, of course, make your own simple wash with this simple homemade recipe that involves using a bit of vinegar, which simply contains white vinegar and water: "acetic acid in vinegar kills bacteria and helps to dissolve the wax and pesticide residues found on the skins of many fruits and vegetables."
You definitely should not be using conventional dish soaps, even highly diluted, to wash produce (or, as my grandmother did, to soak grapes in). Remember, if you use anything to clean your veggies other than water, it should be an edible ingredient.