For fruits such as peaches and apples, which one might eat with skin, some people argue that water do not wash away some chemicals (i.e. pesticides) that get absorbed by the skin, thus advising to always peel them before eating them.

However, considering that the the skin is rich in nutrients, is it unsafe to just wash the fruit with water (and rubbing it with one's hands) rather than peeling them?

  • 1. Most plant skins (citation needed) have an outer layer of cells with semi-permeable membranes. This inhibits any form of molecule to enter the cell and thus the fruit. A simple example: Apply loads of salt to the radish and watch it dry out over time in an effort to achieve similar concentration of salt inside and outside: As NaCl-molecules can’t enter the cell, water has to leave it in order to raise the inner concentration. This is why washing with soap should suffice for both lipophile and hydrophile types of chemicals. (Not an answer because of the citation needed).
    – Narusan
    Commented Jul 8, 2018 at 15:23
  • When something is absorbed by the skin, there is nothing you can do to clean it from the outside - you have to get rid of the skin. If you want the surface of the fruit to be clean, water alone will not do the trick for the same reason your hands will not be clean from all sorts of hydrophobic dirt if you wash them with water alone. So washing with soapy water should remove most hydrophilic and hydrophobic dirt, which puts you in a better position than when washing with water alone.
    – Don_S
    Commented Jul 11, 2018 at 7:32
  • There are other practices, such as using vinegar, baking soda and other household chemicals for cleaning fruit and vegetables. I'm not sure there's a definite advantage to these practices. Worth researching new studies in that field.
    – Don_S
    Commented Jul 11, 2018 at 7:33

1 Answer 1


Your question is hard to give a proper answer.

I think a big (but not complete) answer is already here: How much pesticide remains on a harvested organic fruit?

Anyway, (thanks to) my approach as engineer I can produce another kind, a different answer: a schematic list of statement that you can use to infer an answer by your own:

  1. (Legal) chemicals used in agriculture are safea to human.
  2. Organic fruit will certainly have less chemicals than normal fruitb, so if you worry about chemicals, you should prefer organic fruit and vegetables.
  3. There are different chemicals and each one interact differently with the fruit.
    1. There will be hydrophile („liking water“) molecules and washing your fruit, they will go away.
    2. There will be lipophile („liking fat“) molecules and washing your fruit, they will remain on the fruit, on the peel; an interesting solution is hered.
  4. Part of chemicals stay on the peel, part of chemical are adsorbed inside the fruit, in the fleshc: if you remove physically the peel you will physically remove chemicals in it.

As you see issue is really complex!

a If chemicals used are legal, they have been tested on human.
b https://consumersunion.org/news/cu-research-team-shows-organic-foods-really-do-have-less-pesticides/
c https://www.nytimes.com/2017/11/10/well/eat/do-pesticides-get-into-the-flesh-of-fruits-and-vegetables.html
d https://www.popsci.com/how-to-actually-remove-pesticides-from-your-fruit

  • 2
    "If chemicals used are legal, they have been tested on humans" can you provide evidence to back this up? What about the idea that untested chemicals can be used as they are not proved unsafe? Commented Jul 10, 2018 at 6:07
  • This is an assumption: every chemicals (pesticides included) need to fit laws if producers want to sold them. e.g. "...The EPA regulates pesticides to ensure that these products do not pose adverse effects to humans or the environment. ..." [en.wikipedia.org/wiki/…
    – mattia.b89
    Commented Jul 11, 2018 at 16:13
  • The assumption is slightly wrong in my view. Just because a pesticide is legal, doesn't mean it is free from harming humans. DDT and Paraquat were legal until proven unsafe and only then were they banned. Commented Jul 13, 2018 at 8:11

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