This is a phrase we’ve used in our educational materials. We’ve encouraged folks to be sure to eat the food before it rots, however! There are some exceptions. Honey won’t rot, and we do recommend locally produced raw honey in moderation. I’ve also just discovered that homemade hamburgers left out can simply dehydrate and not rot. So, this phrase can certainly be taken with a grain of salt! Perhaps we might re-prahse it: Only eat foods that haven’t been artificially preserved! My discovery started with this:

McDonalds Experiment

One of our community members posted this photo and the explanation that follows on Facebook:


“I bought this Happy Meal 6 years ago today, July 17, 2017, and thought some of you might like to see how well it’s doing!

Despite the fact the meat is Irish and therefore from an animal raised mainly on grass without growth hormones, although genetically modified soya/corn is part of their supplementary feed. Whatever McDonald’s does to the meat during processing appears to preserve it. The burger it has stayed looking exactly the same pretty much since the day I bought it.

The fries smelt like rancid vegetable oil for the first 5 years and now they’ve turned slightly orange and smell like plastic … delightful!!

The bun just got hard and developed a few cracks, reckon it would hurt someone if you threw it at them.

Regarding “storage”, it sat on top of my Kenwood chef for the first 5 years, gathering dust and comments from visitors to my kitchen. Eventually I got fed up looking at it and put it in a press. No fly has ever been drawn to it, my cats are totally un-interested in it.  They have much more sense than humans!!”

Would a homemade burger rot?

Our community member’s post reminded me of another experiment I saw reported of a 14-year-old hamburger. The burger was even the focus of a television segment on the show The Doctors, which is included in this article. The assumption is that there is some kind of preservative that doesn’t allow the burger or bun to rot.

I investigated a bit further and discovered that this same experiment was done by J. Kenji López-Alt comparing McDonald’s burgers and homemade burgers. The homemade burgers didn’t rot either! I am not sure whether or not the experiment would have had different results if 100% grass-fed beef was used, or whether the bun was made with traditionally prepared sourdough?! J. Kenji López-Alt‘s experiment didn’t include fries, as was included by our community member in hers.

The conclusion made by  J. Kenji López-Alt  is that “the burger doesn’t rot because it’s small size and relatively large surface area help it to lose moisture very fast. Without moisture, there’s no mold or bacterial growth. Of course, that the meat is pretty much sterile to begin with due to the high cooking temperature helps things along as well. It’s not really surprising. Humans have known about this phenomenon for thousands of years. After all, how do you think beef jerky is made?”

We don’t recommend McDonald’s burgers regardless of whether or not it rots due to the ingredients, which Robin Konie of Thank Your Body lists in her article What’s Really In a McDonald’s Hamburger?

What about preservatives?

The concern about preservatives is one I want to highlight, even if it may not be the reason the McDonald’s burger didn’t rot. I will mention here that a preservative is listed in the McDonald’s bun.

Back to preservatives. I came upon this report: a study led by Andrew Gewirtz at the Georgia State University and published in the March 5, 2015 issue of the journal Nature, has uncovered some of the reasons behind the harmful effects of preservative consumption. Shakir Sayani, PhD explains that “the scientists were interested in determining the effects of two well-known preservatives, carboxymethylcellulose(CMC) and polysorbate-80(P-80) in mice. The researchers conducted initial experiments in which they added preservatives to the mice food. The results showed that CMC and P-80 decrease the thickness of the mucosal lining of the intestine that functions as a barrier between the microbes residing in the gut and the intestinal cells. A reduction in the mucosal lining caused the gut bacteria to become invasive. Furthermore, the dietary consumption of these preservatives also led to colitis, an inflammatory condition of the colon.

Perhaps one of the most important scientific finding that results from this study is the disruption of the levels of the microorganisms residing in the gut. Such preservative-induced fluctuations in the number of gut microorganisms led to an increase in weight (and fat).

The present study represents an important advance in sharpening our understanding on the harmful effects of emulsifier consumption. It is likely that similar changes take place in humans upon consuming foods with high levels of preservatives. The increase towards a more preservative-based consumption culture can (partially) help explain the rise in obesity over the past several decades. It remains to be determined and therefore be of interest to investigate which other common preservatives have harmful effects.”

Traditionally Preserved Foods

For thousands of years, people preserved food using lactic-acid and salt. Lactic acid is a natural preservative that inhibits putrefying bacteria. For example, cabbage is preserved by making sauerkraut, cucumbers are preserved by making pickles and milk is preserved by making yogurt, kefir, and creme fraiche. Read more about lacto-fermenation as published by the Weston A. Price Foundation. Also, see this video recorded by Sarah Pope.


The Art of Fermentation by Sandor Katz
Wild Fermentation by Sandor Katz
Real Food Fermentation by Alex Lewin


So what is the moral of this story? Some foods that don’t rot may still be nourishing, and artificial preservatives remain firmly on our avoid list.