eli5 – How does washing vegetables remove possible deadly bacteria?

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So we are always told to wash our fruits and veggies prior to eating them to get rid of bacteria, pesticides, whatever. Assuming my romaine lettuce was contaminated with e. Coli or Listeria or something, how does rinsing the leaves under cold water for a few seconds remove all that bacteria? Especially because we are told to wash our hands with soap AND water, that water alone will not cut it?? Why is plain old water enough for veggies but not for our hands?

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4 Answers

Anonymous 0 Comments

The benefit of scrubbing with warm soapy water is only slightly better than cool running water (maybe a vegetable brush for gunk) when it comes to surface contaminants of fruits and veggies.

On your hands or dishes you can make use of the benefit because they aren’t absorbing any of the soap chemicals, and people are good about rinsing their hands and getting chemicals off. It’s also more useful because your hands and dishes can become caked in things or oily the way fruit and veggies typically aren’t.

With produce people aren’t as good at fully rinsing them off, even if they do they can absorb chemicals first, and you end up ingesting the chemicals which isn’t good for you.

Anonymous 0 Comments

It… doesn’t really. The washing idea is more for macro concerns like dirt, debris, insect bits; all of which can harbor dangerous bacteria and getting rid of them helps tremendously.

But, and this sucks I know, eating raw fruits and vegetables is a solid way to contract food borne illnesses if they are present and this is why our food safety laws and oversight are so rigid. The hope is that our leafy greens aren’t being irrigated with contaminated water and that every step of the way they are being handled and processed in a sanitary manner.

Anonymous 0 Comments

soap also has the double purpose of helping to remove oils, which naturally are produced by skin and trap some gunk to a degree, and us humans frequently work with oils in a lot of ways, such as oils on metals or machines, oils in foods, etc. Typically most fruits and veggies are not oily at all on the surface, so anything stuck to them is more easily washed off. But its not a guarantee for foodborne illness, which is why food safety is so strict even for fruits and veggies, and why there are food poisonings and recalls for fruits and veggies every year.

Anonymous 0 Comments

Soap does a really good job of trapping dirt and yuck. But just water does pretty okay too.

The big difference is grease / oils. Water won’t do shit by itself if something is covered in grease. This is why dish soaps like Dawn say “tough on grease” and not just germs.

So most of the pesticides and supermarket sneezes and dirt from being dropped on the supermarket floor we are try to remove aren’t particularly greasy, thus cold water is pretty effective.