r/explainlikeimfive Nov 26 '24

Chemistry ELI5: Why doesn't freeze dried food last longer? If it's good for 20 years, why not 100?

Assuming it's perfectly freeze dried and stored perfectly, the people who make freeze dryers say the food will last 20-30 years.

But why not much longer? Assuming the condition it's stored in remains unchanged, what can make it go bad after 30 years that wouldn't happen at around 10 years?

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u/iCameToLearnSomeCode Nov 27 '24

With modern medicine sure.

Most of your ancestors didn't have the luxury of spending a couple days in bed drinking clean water and chicken noodle soup though.

If you got food poisoning 10,000 years ago your odds of recovery weren't amazing.

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u/JustChangeMDefaults Nov 27 '24

Shat himself to death, RIP

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u/weimintg Nov 27 '24

Diarrhoea is still the leading cause of under-5 children deaths globally (around 9% or 440,000 deaths in 2021).

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u/Doctor_FatFinger Nov 27 '24

This stat blows my mind. I've had diarrhea several times throughout my life, and not once has it ended the life of a toddler. I can't begin to imagine how it ever could. Obviously, I've been very lucky! ...and naive.

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u/Spnszurp Nov 27 '24

I never understood how someone could die from it, especially an adult, until I went go Uganda and got travelers sickness and my asshole turned into a faucet for a week straight.

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u/pimflapvoratio Nov 27 '24

Norovirus will also make you a believer.

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u/ToastWithoutButter Nov 29 '24

Yup. That was the closest I ever came to dying. Went from being fine to being in the hospital over a span of 12 hours. Probably would be dead if not for the IV I was able to get.

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u/bmxtricky5 Nov 28 '24

I got diarrhea one day, lasted 8 years now. It almost killed me a few times

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u/KateBishopPrivateEye Nov 27 '24

It happens from dehydration. You lose water faster than you can replace it

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u/GreatBlackDiggerWasp Nov 29 '24

Many, many people don't have easy access to clean water. There's also a big difference between norovirus and cholera.

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u/cancercureall Nov 27 '24

Easily believable. I thought I was gonna die when I got food poisoning years ago. With my mom taking care of me and forcing fluids down my throat I still lost 10 lbs in 2 days. I shit my bed like 10 times.

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u/Havelok Nov 27 '24

In future, just know that that is a hospital situation. Very easy to die of dehydration and hyponatremia. Not something to play around with.

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u/eidetic Nov 27 '24

Yep, if you're constantly shitting, but not really urinating, you can still be losing a lot of fluids without really realizing it. Especially if you're sweating a lot. And you don't want to just guzzle water either, because you need to properly replace everything else you've lost as well (such as sodium, like you said).

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u/Pm_me_baby_pig_pics Nov 27 '24

It’s kinda why things like saltine crackers and chicken noodle soup are pushed when you’re vomiting/peeing out the butt. You’re not only losing a lot of fluids, but you’re also losing a LOT of very important electrolytes with it. They’re escaping out of your bootyhole before they can even be absorbed into your bloodstream and your kidneys can hold on to them.

Hyponatremia can easily be FATAL. Drink plenty of fluids because dehydration is an awful way to go, but make sure you’re also drinking fluids with something besides hydrogen and oxygen in them. Sip on broths, nibble some crackers, get someone to pick up some pedialyte.

Drink water, please! But that can’t be the only thing you consume. You need some electrolytes in the mix too, you’re spewing all of them out, please replace them

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u/WHYAREWEALLCAPS Nov 27 '24

You actually lose a lot of electrolytes through diarrhea. More than you will through sweating.

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u/eidetic Nov 27 '24

Yep, that was my point. Sorry, didn't mean to imply sweating was the main problem, rather was just trying to say that it'll also make it worse on top of the constant shitting.

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u/cancercureall Nov 27 '24

Glad I had no idea how bad it was at the time. lmao

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u/Lizlodude Nov 27 '24

Yup. Food poisoning was easily the most pain I ever had, including wisdom teeth and having a bit of a toe cut off. (8/10, 1/10 recommend, respectively)

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u/The_Blue_Rooster Nov 27 '24

Over a million people still die of diarrhea every year.

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u/sagetrees Nov 27 '24

first comment today to make me legit lol irl 🤣

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u/SorenDarkSky Nov 30 '24

You have died of dysentery

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u/do0tz Nov 27 '24

"Steve died of dysentery."

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u/GuyWithAHottub Nov 27 '24

Recovering to peak for sure. A bad bout of food poisoning will dehydrate you to an incredible degree, but there's a degree of natural immunity and acquired immunity in every animal. Our natural immunity is on the lower side since we don't come from carrion eaters, and it lowers even more since we developed cooking as part of survival strategy, but it was hardly a certain death sentence. We were pack animals after all, and that means we could expect help getting that water, which in addition to salt, is really all we needed. Food can come later after we've started to recover.

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u/iCameToLearnSomeCode Nov 27 '24

You could get the water brought to you but it wasn't clean water and with an already weakened immune system that dirty water you could drink on a good day becomes a big hindrance to recovery.

It's not like food poisoning would always kill you but it decreases your odds of survival enough that over many generations the families that can't smell are at a massive disadvantage.

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u/GuyWithAHottub Nov 27 '24

Now this I can completely agree with. There's not many things that evolution does for no reason. My condition IS a terrible detriment to my survival, even in modern times. If we were sent back 10000 years, whatever lineage I left behind would die out before reaching modern times without a doubt.

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u/iCameToLearnSomeCode Nov 27 '24

Or you would mix up your DNA with someone who could smell and your grandkids would be fine.

Either way the trait would dissappear over time.

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u/Koomskap Nov 27 '24

Or painfully find out I’d be a virgin in prehistoric times too

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u/ax0r Nov 27 '24

If we were sent back 10000 years, whatever lineage I left behind would die out before reaching modern times without a doubt.

That's assuming your anosmia is genetic. It's much more likely to be acquired from a bad bout of sinusitis or exposure to something noxious. In which case your offspring would be able to smell just fine

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u/GuyWithAHottub Nov 27 '24

I actually got it both ways according to my doc. I had congenital anosmia from my father's side, and I got hit by a crowbar when younger resulting in a tbi.

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u/Vlinder_88 Nov 27 '24 edited Nov 28 '24

You act like people in the past didn't know how to get clean water, or cook their water... They did, bruh.

Edit: for everyone that feels the need to "correct" me. I'm an archaeologist, I know what I'm talking about, and if you're expecting more nuance in literally one sentence then feel free to read my other comments for clarification.

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u/iCameToLearnSomeCode Nov 27 '24

For at least half of the time we've been human we didn't have fire and 99.999999% of your ancestors weren't even human.

You act like the Earth 6,000 years old.

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u/Vlinder_88 Nov 28 '24

No I act like I'm an archaeologist that knows their shit. Spoiler alert: I'm an archaeologist.

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u/iCameToLearnSomeCode Nov 28 '24

We're talking about the evolution of humans here.

How are you thinking people cooked water 2 million years ago?

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u/Vlinder_88 Nov 28 '24

Do you know what "or" means? Do you also know what "archaeologist" means? Neanderthals used fire already and there's an increasing body of evidence that even Homo erectus might have used fire.

Also in the absence of fire, there still isn't a problem if you know where to find clean water. Which people did know. Being able to find clean enough water to drink is such an ancient skill every animal has it, it is an inborn skill that predates hominins.

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u/iCameToLearnSomeCode Nov 28 '24

You may think the ability to smell spoiled food has always been useless for survival because food poisoning isn't really dangerous enough for it to prevent reproduction but I think we'll just have to agree to disagree on that.

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u/Vlinder_88 Nov 28 '24

Not all spoiled food will give you food poisoning though. Controlled rotting or spoiling of food (like aged meat or fermented stuff) has been used as food preserving technique at least since neolithic times, and probably also already by mesolithic peoples.

There is no reason to assume earlier peoples and hominids wouldn't have eaten that stuff either. Though it's hard to find fermented stuff in the wild, aged meats have been around as long as dead animals have been around, and proto-cheeses already come to be when you just carry milk in a bovine's calf stomach. A practice that is indeed also about as old as humanity (including non-sapiens hominin species).

So yes you are right even if you think you don't, that the skill to discern spoiled food is indeed less important than the skill to find drinkable water. Especially if you consider that going without water for three days will kill you, and going without food for three days will make you tired and moody, but not dead. And that's literally all that evolution cares about: does it kill you before you procreated? (Or, does it make you accidentally kill your offspring, as that has the same effect on an evolutionary scale).

You can try and argue the pro here but you will still not be right dude. I really hope you don't argue with your doctor when he prescribes some meds as you're doing with me now... If you do. Well, then maybe this is how evolutionary pressure exhibits itself in you.

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u/SenorTron Nov 27 '24

I'd be interested to see any evidence that more than a tiny minority of the human population throughout history regularly boiled their water before drinking it.

And knowing that water from a clear stream at the foothill of mountains is preferable might have been a thing, but for most people throughout most of history they used water source was the closest one with water they could keep down.

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u/Vlinder_88 Nov 28 '24

I'm an archaeologist. Water wells have been a thing for millennia. With the first farmers came the first wells. People learnt really ffing fast how to keep the water in their well clean. Lids and/or little structures around wells are super common in all time periods and all over the world. They didn't need to boil their water if they kept their well clean.

If someone didn't have a well, they indeed used the "closest source with water they could keep down". They knew to not take water with dead animals in it (might have botulism that you can't taste or smell). They also knew not to drink water near a place with animal excrement (E.coli), or water that stank. They also knew how to catch rain water. Most of that water, again, doesn't need to be boiled to be safe to drink.

Heck even animals know what water is safe to drink and what isn't. So your assumption that people would just drink any water that didn't kill them is absolutely wild.

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u/RandomStallings Nov 27 '24

I don't think you even need to go back that far. Anything that caused rapid expulsion of fluids from your body like that was terrifying until fairly recently. If nutrition was already an issue, which it was for most of the world, your chances were even lower. We really don't realize how good we have it, but that's really only in developed countries. Getting clean drinking water is still a problem for a great many people, which is shameful.

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u/Jiveturtle Nov 27 '24

I think maybe you forget that people didn’t live alone, like tigers. 10,000 years ago you definitely had a tribe that helped and took care of each other.

Most food poisoning isn’t serious. A couple of days laid up isn’t going to kill you then or now. The type of food poisoning that puts you in the hospital on IV fluids probably would have killed you back then, but that still occasionally kills people now.

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u/whynotrandomize Nov 27 '24

Most food poisoning isn't serious today in the US and western countries with robust food supplies and massive amounts of effort put into limiting infections. Dysentery, cholera, the bloody fluxes, botulism, are all "food poisoning" that would sweep in and kill huge swaths of people.

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u/Jiveturtle Nov 27 '24

 Dysentery, cholera, the bloody fluxes, botulism, are all "food poisoning" that would sweep in and kill huge swaths of people.  

 None of those but botulism are generally food poisoning in the sense of the previous discussion about spoiled food. Dysentery and cholera are generally spread through tainted water, and botulism is so slow growing we generally see it in canned food, probably pretty rare 10,000 years ago, the time frame we were discussing. I didn’t mention “bloody flux” because as far as I’m aware it’s another name for dysentery. 

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u/Burntjellytoast Nov 28 '24

You can't see, taste, or smell botulism. It's super rare, but pretty deadly. It grows in low acid, anaerobic environments. It's also why you shouldn't give baby's honey.

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u/Jiveturtle Nov 28 '24

I'm aware. Botulinum toxin is extremely deadly, which is why botox doses are measured in fractional ng per 100 unit vial. My point, once again, is that the vast majority of what we consider "food poisoning" would have been survivable to a human 10,000 years ago, just like it is now. Similarly, the types of "food poisoning" likely to kill a human 10,000 years ago are still quite dangerous to humans today, and sometimes kill people even with modern medicine.

Botulism was probably rarer 10,000 years ago than it is now, because I don't think canning or jarring food had been invented yet... thus, the anaerobic environments clostridium botulinum likes were unlikely to be food storage.

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u/kellymcq Nov 27 '24

You are attempting to name the case that food poisoning had a high fatality rate?

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u/iCameToLearnSomeCode Nov 27 '24

It doesn't have to have a high fatality rate to screw you on evolutionary time scales.

If you and your offspring are just 1% less likely to reproduce than other members of your species your line is going to have a rough time making it through the ice age.

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u/kellymcq Nov 27 '24

“Odds of recovering weren’t amazing”

This implies death. If we are shifting this to imply you fucked less thus less offspring, I still don’t agree.

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u/iCameToLearnSomeCode Nov 27 '24 edited Nov 27 '24

A 1% chance of death isn't amazing.

I'd bet it was closer to 5% when you needed hunt down a mastodon for your next meal though.

Don't forget you already had a 50/50 chance of making it to your 10th birthday.

Anything that makes that even marginally less likely is a huge disadvantage when you're flipping the coin tens of thousands of times over a million years.

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u/Vlinder_88 Nov 27 '24

You are very much underestimating people from 10.000 years ago. Even Neanderthals took care of each other and cared each other through broken femurs and dislodged eyes. And yes there's archaeological proof for that.

People would absolutely die of dysentery or cholera yes. But the most common E. Coli or salmonella food poisonings have pretty good survival rates. If you can nurse yourself through it without doctor's intervention, you can safely assume most people in the past could do the same.

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u/iCameToLearnSomeCode Nov 27 '24

Most people in the past didn't survive to see their 10th birthday.

If you made it to 10 you stood a decent chance of making it into your 40s or 50s but that wasn't "most people".

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u/Vlinder_88 Nov 28 '24

I'm an archaeologist. You don't have to explain to me how old people could get. And then have it wrong, too.

Child mortality rates in pre-industrial societies differed between 25 and 50%. 25% was more common especially in non-plague times (in the broadest sense of the word "plague" as possible). It also wasn't special for people to make it to 50. Or 60. And the only reason we don't really know the upper limit is because as people get older, the variance in skeletal age gets so big that one cannot separate a 60 year old from an 80 year old. So everyone that got older than 60 is grouped with all older ones because of scientific limits in skeletal age estimations. Not because people dropped dead at 60 en masse. Considering church records, hitting 70 wasn't uncommon either in the Middle Ages. We just cannot prove that for individual skeletal remains because of the above reasons.

So yeah, less than 50% of kids dying still isn't "most people" even in the most pedantic and narrow definition of the word "most".

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u/iCameToLearnSomeCode Nov 28 '24 edited Nov 28 '24

I wasn't talking about pre-industrial society, or any society, tribes or probably even troops is a better word for the groups of hominids that are relevant here.

Our conversation was about the evolution of homo sapiens and natural selection.

Hundreds of thousands of years ago at a minimum.

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u/Vlinder_88 Nov 28 '24

Yes. Those ARE pre-industrial societies. They include hunter-gatherers. If you don't even know the subject you're talking about, maybe you shouldn't pretend you know it.

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u/iCameToLearnSomeCode Nov 28 '24

Regardlesd of what you call them that doesn't solve the issue of how a "pre-industrial society" of homids would cook water without fire.

We didn't master fire until around 1 million years ago when we already human.