So I was cleaning out my car and found a McDonalds French fry. as I don't eat anything in my car I know exactly who and when this fry is a result of. The when is + 10 months old and it could pass off as one just prepared. How could this be?

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    $\begingroup$ Dehydration prevents decomposition. Frying stuff basically replaces water with fat. Your once-upon-a-time potato was basically mummified at maccers. $\endgroup$ – AliceD Dec 11 '14 at 3:05
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    $\begingroup$ Although arguably not the most ordinary question, this question is not opinion-based. $\endgroup$ – AliceD Dec 11 '14 at 12:13
  • $\begingroup$ Thank you @ChrisStronks I wasn't expecting the initial down votes here this is pretty much day one biology. I guess we have to shove it down peoples throats. McDonald's french fries are soaked in hydrogenated oil. Saturated fat's which are entirely hydrogenated have a very linear structure thus making a molecule stack one on ... $\endgroup$ – rhill45 Dec 12 '14 at 0:53
  • $\begingroup$ top of another, sealing off all moisture. Decomposition occurs from the inside out. At the time the french fry was fried it was essentially sterilized on the inside and then as it cools it is sealed by the hardening saturated fat. I had to start taking Lipitor yesterday so I thought i would post this question. Good choice with the mummification analogy :-) i'll give it to t. Abrams and less you want to post something $\endgroup$ – rhill45 Dec 12 '14 at 0:53
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    $\begingroup$ Is this straight out of 'Supersize Me?' $\endgroup$ – HDE 226868 Dec 12 '14 at 1:07

This controlled experiment of burger decomposition explains in detail why fast food burgers do not decompose easily. The same can be applied to fries, which are smaller and come dehydrated from the frying.

The main take-aways from this experiment are:

1: Dehydration is the main reason why fast food fries/burgers do not decompose easily. Placing the burgers in a ziplock bag, preventing dehydration, causes the burgers to decompose.

2: Since an unsalted, home-made burger did not decompose, preservatives, chemicals, saturated fats, and other components are unlikely to be the case of the fast food burgers not rotting.

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    $\begingroup$ +1 for using "take-aways" - even though I suspect it was not a deliberate pun seeing as we are talking about fast food, it tickled me. Good clear answer with references too. $\endgroup$ – rg255 Dec 14 '14 at 0:11

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