Honey apparently does not naturally decompose. Are there other foods that don't? Why?

pa5tabear

I heard that honey doesn't decompose. I've also heard this about peanut butter. Would they decompose if mixed?

What stops these from decomposing?

I'd expect that any high energy molecule would eventually react into some lower energy state, regardless of whether microbes are involved.

Ygggdrasil

Here decomposition is related to bacterial decomposition. Bacteria do not grow in honey, peanut butter, and other like substances because these substances have a very low water content and will actually dehydrate any bacteria that lands in the substance. These substances can still decompose chemically, but at room temperature, any chemical decomposition occurs very slowly.

See the related PF thread here: http://www.physicsforums.com/showthread.php?t=615560

onomatomanic

Low water content is definitely a major factor. Fresh meat and fish require cooling (which slows down all biological and, to a lesser degree, chemical processes) to last more than a few days at most. Dried, however, they can last for a much much longer time.

Another, probably less important, factor is that honey contains natural antibiotics. There are a few other foodstuffs which do, and presumably all of those keep for a comparatively long time.

Off the top of my head, I can name cocoa and garlic. Cocoa is a seed, and those are naturally more resistant to all kinds of decomposition - they need to be, to fulfill their function. Garlic works well to illustrate this, though. Its water content is, at first, not particularly low, and yet, when stored under appropriate conditions, it desiccates to the point of crumbling to dust before ever becoming moldy.

pa5tabear

What about flour or rice? Both seem very low in water, but I've had meal moth caterpillars growing in these. The difference I can think of is that the moth caterpillars do not feed via diffusion. They physically bite/chew off whatever they consume. This means that low water concentration will not block nutrient entry, as it does with microbes.

Has anyone had problems with mold/bacteria on their grains?

onomatomanic

The way I understand it, it's being immersed in the honey (or whatever), rather than trying to eat the honey, that's already harmful to the bacteria. Macroscopic organisms can eat the honey without immersing themselves in it - and even if they do become immersed, it's only a relatively small number of cells which are directly in contact with the substance; most are protected simply by not being surface cells. Furthermore, surface cells are specifically designed to withstand that kind of thing, so there may not be any damage to those anyway.

ps: Of course, if an insect does fall into honey, it usually will die, so the end result is the same as that for the bacterium. But that's due to drowning, which is something else altogether. :)

jim mcnamara

pa5tabear - does decomposition include include being consumed by larger forms of life, like insects? I would say 'no'.

The bugs came from the fact that flour and other grains and ground grains have a few insect eggs scattered around. For example see:

http://en.wikipedia.org/wiki/The_Foo..._Action_Levels

What this means is that most grain products have the potential for bugs to show up sooner or later when stored dry and at room temperature and sealed against intrusion by insects, fungi, and bacteria.

As other posters mentioned, bacteria and fungi are the primary food decomposers.
Adding large amounts of table salt to food or dehydrating food generally slows these guys down, as does freezing and (to a lesser extent) refrigeration.

This is the reason for food companies irradiating food. All of the bacteria, fungi, insect eggs, etc., are killed by radiation. This makes the food shelf stable for very long periods of time because the food is in effect sterilized.

Let's not off the deep end on the safety of irradiated foodstuffs. This thread is not about that.

Decomposition, contamination, and waste of stored foods is a huge problem. See:

(Chapter 3 starts with a graph in this publication)
http://www.fao.org/docrep/014/mb060e/mb060e00.pdf