This has been a real mystery for me at work. For the past three days I've eaten salads for lunch. I used a plastic bowl with a lid and when I was finished with the salad, I didn't rinse out the bowl and left my plastic fork in the bowl with the lid sealed over night. Well, the next day, when I open the lid, the prongs of the fork are always broken off... like they melted or something. This has happened three days in a row.

Is it something to do with the sealed container, or the dressing residue? Each day I used a different salad dressing but the result was the same. The fork was just laying in the bowl so there's no reason it should be broken in pieces the next day...

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    $\begingroup$ We'll need more info about those salads in order to properly answer this query, and for sure need to find out about that dressing in detail. Please amend your post with more information and we'll hopefully get some resolution on the fork issue before any further negative utensil-related incidents occur. $\endgroup$ Commented Oct 2, 2015 at 22:31
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    $\begingroup$ If it's at work, using a communal fridge, suspect a coworker with odd sense of "humor". $\endgroup$ Commented Oct 4, 2015 at 1:36
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    $\begingroup$ DrMoishe Pippik has a point. Try it at home on a weekend. // The only other idea is that some oil could be dissolving into the surface layers of the plastic creating a lot of stress. That would seem really weird though. $\endgroup$
    – MaxW
    Commented Oct 25, 2015 at 6:42
  • $\begingroup$ Those cheap plastic forks carry a lot of internal tension from the production process, check google for pictures on "plastic fork polarised light". $\endgroup$
    – Karl
    Commented Aug 23, 2016 at 16:13
  • $\begingroup$ It may be due to acids present in the salad. $\endgroup$ Commented May 11, 2019 at 15:59

1 Answer 1


It's highly probable the fork is made of some kind of biodegradable or compostable material designed to mimic plastic. Most plastics, especially ones used to make utensils, are stable under the conditions you described. I would carefully inspect the fork for any numbers molded on the plastic shown on the chart.


Biodegradable "plastics" are intentionally designed to become unstable and breakdown overtime. It's possible the salad dressing is made with vinegar or citrus juice which is acidic enough to breakdown or at least react with the material. Water can have the same effect, but may take longer, since you don't want the fork disintegrate while you're eating.


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