Point me to the propper post if this has been discussed already.

For almost a decade I travelled with different Museum exhibitions installing and de-installing the heavy/fragile artifacts. During one specific exhibit we were installing Egyptian mummies. It was really amazing to do and had really great time working with the Egyptian currators that travelled with the show.

What I found out was they used nitrogen filled glass cases for all of their mummies. The nitrogen protected their bodies from insect and microbial attack. They claimed a 100% nitrogen environment is unlivable for any known animal. So what I'm wondering is; what are the, if any, limitations on using nitrogen to preserve grain or fruit or even meat? Will bananas stay green in a box filled with nitrogen? Will hamburger stay red and edible in nitrogen? I understand a fifth grade lvl of innert gases but am curious about what you guys might have to add. For all I know this is the way people are preserving their food stores now.

What do you guys think/know?

Plastic bags of chlorinated lettuce salad leaves in inert Nitrogen are available at the supermarket. They decompose at a remarkable speed once opened. Which is why I don't buy them.

Ok so there's rapid oxidation after breaking the seal. I wonder what chemical process is going on during the lettuce's nitrogen sleep. Any bio/chemical folks out there that know?

I know nothing about food, but I know you can buy nitrogen to add to opened bottles of wine to keep them fresher.

Yes, nitrogen will kill any living thing, but I wonder what effect it has on regular, sub-cellular enzymatic activity? If the enzyme needs oxygen to function or be regenerated it would stop working but there might be some "decomposer" enzymes that could keep going. Let me ask our resident biochemist about that.

I think a bigger problem would be from the lack of water vapor/humidity causing meats and fresh plant matter to dry out. Not a problem with grains and seeds as you can already buy nitrogen-packed packets of seeds for emergency gardens, but juicy stuff would probably suffer.

-Blast

AFAIK, I've never heard of nitrogen being used in enzymes. Certain things use nitrogen as parts of molecules (such as nitric oxide), but never strait N.

Enzymes don't typically need something to function. Generally, once the protein (enzyme) is made, it kind of just goes on it's own power. Some things will need a substrate to work, so another molecule or protein needs to bind the enzyme. There are also enzymes that use ATP (which needs O2 to be generated), electrical gradients (which need ATP to maintain the gradient), or enzymes that catalyze reactions that cause a cascade effect into the cell, with the end product being the final product.

So, really, I don't think nitrogen "kills" a cell like you're thinking. Rather, it's the lack of oxygen that causes the production of ATP to stop, and without that the cell can't keep making the proteins and enzymes it needs to function. IIRC, apoptosis (cell death) occurs when pre-packaged enzymes escape into the cell (example, hydrogen peroxide). But, I don't recall if that's O2 dependent, or if the O2 "holds back" that reaction.

Unfortunately, there is yet no perfect food preservation method, YouTube videos about the ever-fresh McDonald's meal notwithstanding.

Using gasses like nitrogen or carbon dioxide will kill off bacteria, insects, rodents, etc., but they still can't totally prevent the degradation of raw food. I've never tried it, but I would expect that fresh food kept in nitrogen may not get moldy or spoil in the usual sense, but it would still decompose over time. Eventually, the nutritional value will decrease to the point that it may not be worth keeping and/or the taste will become inedible. Same thing with canned foods, MRE's, etc. You may not get sick eating really old canned foods, but you may gag on the taste or the texture.

Or think of aged beef. The methods used now allow the meat to age with very little, if any, bacterial growth, so the meat really doesn't "spoil" at all but it does break down and get soft (a desirable thing, in this case). If you just kept aging the beef, I assume you'd get some sort of gooey mess in the end.

No one is worried about the taste of mummies, and they are already preserved, so the nitrogen is really more of a secondary preservation strategy, not the main one. Anyway, just my 2 cents.

This is why the Twinkie is perhaps the perfect survival food. Since it starts out with no nutritional value, it can't degrade very much, and no self-respecting microbe would infest it.

As far as gagging on the taste and texture of old canned food, I already have that reaction to canned rutabegas.

Okay, I talked to our resident biochemist. According to him most enzymatic activity will continue in the cell for quite a while after an animal dies. Lack of oxygen/excess of nitrogen has no effect on these metabolic mechanisms. However, the lack of blood flow means cellular waste products aren't removed nor are fresh nutrients and chemicals moved to the cells. The interior of the cells becomes very acidic which leads to the breakdown of cell walls.

Meanwhile, anaerobic bacteria are multiplying out of control. Normally they are kept in check by your immune system as well as...defecation. Half the dry mass of stool is usually bacteria. Since the animal isn't defecating the bacteria remains inside the body to multiple and "eat" the surrounding flesh. Cells rupturing due to increased acidity flood the anaerobic bacteria with more food. These bacteria are also producing waste products and gases.

The only way to really prevent this is by removing most of the water from the carcass. Without water everything grinds to a halt.

-Blast

Twinkies lol! Yeah I guess if you have a "food" item that even bacteria won't eat that alone makes it last a long time.

All advice sounds resonable. Moisture seems to be the factor that trumps using nitrogen as a preservative.

I'm guessing you can extend the shelf-life of dry grains and beef jerky (cow mummies! yum)using 100% nitrogen. I'm curious to know what the shelf-life of wheat flour or peanuts is. Something dry and solid should benefit from using nitrogen.

I've heard about how some stores pack their salmon in CO^2 to keep it looking red and fresh. Can fungus separate the carbon and oxygen as a food source?

Anyway, thanks for the replies. Gonna stick with the salt brine and vacume seal for my vegies.

D

It's actually CO, not CO2 that they pack meat in. It binds to the hemoglobin, and keeps it red. CO binds to hemoglobin better than O, which is why it's toxic. CO2 would actually make the meat blue!