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When I asked about food preservation for 2-3 centuries, some commenters insisted that if I have technologies to preserve living humans for that long I should have no problems preserving food (with almost intact nutritional values). That made me wonder if this idea is actually true.

Living organisms have a lot of mechanisms that keep them functioning for extended periods of time, prevent decay, deal with infections, and even repair mechanical damage. Many animals and plants can live for decades while exposed to elements, pests, bacteria, viri, and physical trauma. Their chemistry stays more or less stable over that time. But once they are dead, it takes just a bit of time for them to decay (the exact time depends on many factors, e.g. environmental conditions, chemical preservatives concentration in tissues, tissue types).

Question:

Dead tissue or a living organism (as classes, not specific types of tissue or organisms), which is easier to preserve for 2 centuries in a condition as close to original as possible? (with focus on biochemistry rather than the preservation of a specific tissue)

'Preservation' in my question is used in this sense:

the activity or process of keeping something valued alive, intact, or free from damage or decay

with emphasis on 'free from damage or decay'.

This question is not limited to currently existing technologies. Developing technologies or theorised technologies are fine, as long as they have solid scientific backing. For example, genetic engineering is fine (within reason), cryosleep is not (unless you provide citations for successful reanimation after at least a year of storage).

Edit: When I am talking about preservation in a condition as close to original as possible I mean exactly it. If you are preserving a piece of meat it should stay a piece of meat after 2 centuries (or can be reconstructed as such if some tricky procedure is used; ideally it should have the same texture, taste, and nutritional value since this is the case for living organisms). Most of the chemistry and physical properties should stay the same at the time of examination (before preservation and once it is finished). The sample does not have to consist of exactly the same physical atoms, molecules, or cells (it is not possible for a living organism) but it should be recognised as the same tissue/organism in close to original condition by an average human and have the same functionality.

Please assume that whatever conditions are needed for preservation can be maintained for the duration of the preservation experiment without interruption.

Edit 2: I am much more interested in a comparison between arresting decay in dead tissues and sustaining (or improving) natural bioprocesses in live organisms.

I also want to note that freezing does not leave organic matter intact. There is damage associated with freezing/thawing that has to be quantified and figured in. I wrote about it and other aspects of food preservation in my notes for another question.

Edit 3: I am looking for hard science with citations, numbers, and figures. I appreciate general thoughts on the subject, but it is really hard to compare the advantages and disadvantages of different solutions and approaches if I have nothing but words to rely on.

I do use 'food test' (if something was edible before it should keep the same nutritional values after 2-3 centuries) because it is an easy way to test many answers, but this is not a question about food preservation. The type of organic material does not matter at all, what is really important is its integrity and physical properties, including biochemistry.

This is not a museum project. All organics should be usable in a regular manner after 2-3 centuries.

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    $\begingroup$ If you can preserve a living human for 200 years, can’t you preserve a living steak (aka cow) by the same means? The steak being dead can only add options. $\endgroup$ – StephenS Sep 3 at 4:24
  • $\begingroup$ If my method of preservation relies on biological processes that exist only in living organisms (self-repair, waste removal, etc.) then obviously no. Theoretically, I can tweak human genes in such a way that the cells become immortal. My human will become virtually immortal (still need life-support systems natural or artificial). But this will do nothing for their body if they die in a car accident. $\endgroup$ – Otkin Sep 3 at 4:31
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Dead:

The difference between preserving living tissue and dead is that you have to keep living tissue viable, while dead tissue you don't. Everything you can do to living tissue, you can do to dead. So by a huge margin, dead tissue is easier. Every preservation technique you can use on organic material, you can use on DEAD tissue, from embalming to mummification. Mummies have lasted for thousands of years, and there are remains of long-extinct species in jars of formaldehyde that are hundreds of years old and still recognizable. If you aren't fussy about small chemical changes but only care about the form, I think it would be easy to preserve organic material indefinitely (if this is secretly a food question though, it might not be edible). The evidence may be challenged, but there is some evidence that preserved soft tissue might last millions of years.

There is ONE circumstance where you are better off with living tissue, and that is that living tissue regenerates. A plant can keep growing as a sort of immortality, and if the plant is maintained and capable of continuous growth, it keeps living. If you can make a biologically immortal person, then that person can live forever by simply living. On a planet or on a spaceship, they keep living. BUT, even a person capable of living forever may grow suicidal, and the water system to an immortal plant or fungus can get switched off and it can die. You need to maintain the entire apparatus of life constantly for something to stay alive. Keeping things alive is extremely energy and resource intensive, so if the goal is to have a person alive after 200 years on a spaceship, it is semi-impractical and the whole reason people want to invent cryo-sleep.

Further, the immortal organism isn't the identical tissue, but regrown and recycled tissue. They are functionally a clonal colony Just because an "immortal" fungus is centuries old, that doesn't mean it's the exact same fungus. Mutations can still crop up in an organism (ie cancer), and the cells aren't the same cells. We haven't come up with a great way to immortalize people yet, but things like brain tissue would need to die and get switched up. Physical stuff eventually wears out.

This is not to say a living organism CAN't be preserved for a long time under appropriate conditions, but it would need to be specialized for this function. a seed, for example, can remain viable for thousands of years.

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  • $\begingroup$ On top of all that, dead tissue is less likely to resist being thrown into a vat for conservation. $\endgroup$ – The Square-Cube Law Sep 3 at 2:59
  • $\begingroup$ This answer does not contain even one link to a source despite the question being tagged as hard-science. It also ignores a condition stated in the question 'as close to original as possible'. I hope you are not suggesting that mummies are close to a recently deceased person. $\endgroup$ – Otkin Sep 3 at 3:03
  • $\begingroup$ @Otkin Mummies are simply an example of preservation for an extreme amount of time and would not be needed for preservation for mere centuries. Tissue in formaldehyde is similar to the original tissue for a long time except on a chemical basis. By that "as close as possible" you seem to imply if the tissue isn't alive, it isn't the same. Even living tissue isn't the same tissue anymore after this long. $\endgroup$ – DWKraus Sep 3 at 3:45
  • $\begingroup$ If I could eat something before the procedure, but I cannot do it after the procedure, I would hardly describe the change as minimal and the result as close to the original as possible. If I grow my tree for 200 years it will differ from what I started with in size but it will still be the same tree chemically and would have the same material properties. $\endgroup$ – Otkin Sep 3 at 3:52
  • $\begingroup$ @Otkin The part of the tree that is alive is completely different cells. The part that WAS alive is dead and preserved. The form is preserved because of the dead wood of the trunk. That's why a tree can rot from inside if decay organisms can access the wood. A tree is hardly the same 200 years later. Tissue dead 200 years ago that is still dead 200 years later can be essentially identical if it was already preserved when the clock started. $\endgroup$ – DWKraus Sep 3 at 4:05
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Dead

You can vacuum seal and then irradiate dead tissue to kill everything living inside of it and then store it at a moderately cold temperature to result in only minimal tissue damage. You can then, if you so choose, pop that dead tissue out of the vacuum seal 200 years later and grill it into a steak, assuming that you had steak to start out with.

Most living things have a lifespan of under 200 years and once you preserve living things, they generally wind up dead - cryonics does not work and there's no indication outside wishful thinking that it ever will work. Preserving living things will wind up with dead things, and dead things are similar to living things, but not as similar as dead things are to dead things.

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  • $\begingroup$ How minimal is minimal? Will the steak have the same nutritional value after 200 years as the day it was frozen? Does it apply to any dead tissue? Will plant tissue hold as well as meat with your proposed methods? For comparison, I can grow an algae colony for 200 years and it will stay pretty much the same in a stable environment. $\endgroup$ – Otkin Sep 3 at 3:46
  • $\begingroup$ 1) Damage on the cellular level, mostly to sensitive molecules like DNA. 2) You're not freezing it, you're storing it at a low temperature after vacuum seal and irradiation, and I would expect it to have roughly the same nutritional content fresh from vacuum seal. 3) Most dead tissue, though some works better than others. 4)Yes, but its not going to be the same algae colony and therefore not preserving. That's like saying you could replant generations of fruit trees and it would still be an apple tree at the end. If that's what you mean by preserve, you need to clarify the question. $\endgroup$ – Halfthawed Sep 3 at 11:18
  • $\begingroup$ Chilling even in controlled atmosphere does not work as a long-term preservation method for organic materials. Bacteria are only one of the reasons for organic matter decay. Without properly functioning biological mechanisms most organic tissues are unstable. Cells do a lot of work to preserve their integrity and composition. Please note that my question does not ask about living tissues, but about living organisms. Keeping tissues alive outside of their original organisms is a very different and much more complex issue. $\endgroup$ – Otkin Sep 3 at 21:21
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This is link to Food preservation types and technique : https://en.wikipedia.org/wiki/Food_preservation

The answer it's very difficult, because there are many factor to consider, bacteria, yeast, external agent, wheater condition, moisture, pathogens for a dead flesh, the duration of a dead tissue depends on type of tissue.

A good example of food preservation is military rations they can last until 50 years

I think that there's no correlation between living humans and dead tissue, because a living being have "energy" to maintain and a process of regeneration (human about 70-80 year, a turtle 150 year, greenland shark 400 year this is an average value).

Discussing with a futuristic tech you can use Amber to store the tissue after a previously preparation. You can continuously clone the tissue to preserve, actual tech can reproduce skin from staminal cells.

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  • $\begingroup$ What is Amber? Could you explain or provide a link? $\endgroup$ – Otkin Sep 3 at 9:54
  • $\begingroup$ en.wikipedia.org/wiki/Amber, it's a resin that in milion years ago entraps insect and other $\endgroup$ – DG79 Sep 3 at 10:10
  • $\begingroup$ Can amber be used to store food rations? My goal is not a simple preservation, but preservation for future use. $\endgroup$ – Otkin Sep 3 at 10:16
  • $\begingroup$ i think that if you want the better result is to stabilize the food with the right method of preservation both durability but also flavor and after put in a lont term storage, that can be amber or a can filled with nitrogen (used for cryopreservation and inert atmosphere, in alimentary industry is used to prevent rancidity). $\endgroup$ – DG79 Sep 3 at 13:19
  • $\begingroup$ @Otkin the amber reference is assumedly a tie-in to Jurassic Park, where the mosquitos that bit dinosaurs are trapped in amber and scientists extract DNA from them to recreate dinosaurs. en.wikipedia.org/wiki/Jurassic_Park $\endgroup$ – DWKraus Sep 4 at 3:27
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Given that the OP has added or clarified a condition to the question:

You are too focused on food and livestock. While I indeed need to feed my crew, I need organic matter for other reasons, too. Moreover, I need them to be as close to original as possible. For example, I need most of the DNA and proteins intact and easily accessible for manipulation in many ways. You correctly identify problems associated with keeping animals alive while in a coma, but you ignore all chemical changes to dead tissue. I also realise that this whole topic of keeping organic matter intact for long periods of time is highly underappreciated and people tend to oversimplify things.

Alive is the Only Way to Go!
Since you need to be able to access and manipulate DNA and other biological materials, in addition to having access to crew rations, the best solution will now be twofold. Storage of frozen food for long periods of time has already been discussed (focused on meat). But you will also need a way of preserving living tissue. The best way to accomplish the feat is to keep partially prepared food in the deep freeze as already discussed but also to step up keeping live plants and animals in some kind of habitat.

You could consider, as part of ship design, a large free range biohabitat. Stocked with small livestock such as chickens and rabbits and an appropriate predator species, its environment monitored and adjusted by ship's AI, your crew might just awaken to fresh fried chicken!

This is unlikely to work long term, as disease will be problematic and population spikes and catastrophic dips may lead to extinction of the biohabitat. While balance issues may pose tricky problems, at least the time span is short enough that you might be able to pull it off.

At journey's end, the biohabitat will contain sufficient biological matter, in the form of living animals and plants as well as decomposing matter and compost that can be used for other purposes, such as manipulation in order to grow artificial meat or to make pharmeceuticals, vitamins, hormones, etc.

The advantages to the split system are numerous: you will have fresh food available to the crew upon awakening; you will have a ready source of biological matter onboard; you will also have something approaching a natural habitat for the crew to enjoy while performing onship duties at the end of the journey. Even though you propose a very high level of technology, you don't have synthesisers capable of extruding complex biological material. A biohabitat (or two) will solve the issue of "preservation", because nothing beats a living plant or animal for providing biomatter.

Although we discussed keeping animals in a coma, inducing a state of torpor will pose similar problems. The main problem is the simple fact that animals are mortal creatures. They have a basic life expectancy that very few will survive, and will be almost impossible to overcome while incapacitated and supported by machines. Barring some kind of "stasis field" technology, there is just no way to "store" a plant or animal and ensure that it will continue to exist, in a living state, beyond the capacity of its kind. The life span of many crop plants -- tomatoes, lettuce, etc is literally a year. Though others may last much longer -- grapes, apples, other fruit trees. The life span of food animals rarely exceeds 20 or 30 years. This is the insurmountable problem of any kind of "storage".

The advantage of designing biohabitats into your ship is that the plants and animals will exist in something approaching their natural state. The biohabitat will have night and day cycles, can have seasonal cycles, can have artifical weather conditions and will be self sustaining, once fabricated.


Original Answer

Definitely Dead
The good folks over on Cooking.SE have asked this very question. The long and short of it: properly prepared meat (raw, vacuum sealed, maybe irradiated, kept frozen (0 deg F)) can last indefinitely.

This Woman's Day article about freezing meats quotes an FDA fact sheet about freezing foods. The pertinent language reads: "Food stored constantly at 0 °F will always be safe. Only the quality suffers with lengthy freezer storage."

Quality suffers, according to a comment within the C.SE query, thus: Generally, meats dry out (freezer burn) when frozen before they become unsafe to eat. You can reduce the drying effect by double-wrapping meats, and a vacuum sealer is especially helpful. Freezer burnt meats become tough and grainy, but can normally still be used in stews, stocks, and other preparations that hide the damage. (Bruce Alderson)

I think 200 years of cold storage should yield an edible, if not terribly palatable, meal.

Counterexample
But what about living tissue? Living tissues can indeed be kept, though not really "preserved" for a long time. This process is essentially an induced coma. Essentially, the person in a coma exists in a state of deep unconsciousness. Presumably, an animal placed into an induced coma would similarly exist in a state of unconsciousness.

The record for longest coma is something like 37 1/2 years. Not quite long enough for your purposes! The main problem with this kind of storage of living tissue, whether human or animal, is that the body continues to grow & develop. At least to a point. People in comas are not in any kind of "stasis" -- they are still susceptible to environmental diseases and may still develop cancers. Finally, no living thing this side of the veil is immortal: a person in a coma will eventually die. Most likely from complications of the coma itself; but at the last, even a comatose person will die of old age.

There are plenty of bad things that can happen to a comatose person, ranging from infection to decreased bowel and respiratory action, lowered blood pressure, bed sores and atrophy from disused muscles. A food animal stored in such a way would almost certainly suffer the same physical degradations. This is not a viable alternative for the simple reason that it's the muscle tissue of the animal your crew will be hungering for when they wake up at journey's end!

Resource Comparison
Dead tissue: one time Earthside preparation including initial butchery, multipacking of raw flesh with irradiation & vacuum sealing, rapid freezing. Shipside requirements: freezer units that are accessible to crew upon waking. Ship's AI should be programmed to monitor temperature and perhaps vacuum conditions of the freezer units; should also be able to quarantine a/o jettison compromised or nonfunctional units. Results: guaranteed.

Live tissue: livestock animals will need to be initially processed (bathed, decontaminated, quarantined) before entering Earthside facilities. Once there the animals will be anesthetised, cannulated, unconsciousness induced, intubated, and loaded into harness cradles. The harness cradle serves as a suspension storage apparatus with attached medical grade machinery (respirator, multicapacity IV pump). Shipside, the suspension cradle will be attached to the on board MPS (meat preservation systems), which will include all necessary lines to central storage facilities, including room air, oxygen, potable water, IV nutrition, IV fluids, and an assortment of pharmeceuticals. The MPS will also feature a physical (passive) exerciser (an attempt to preserve some muscle mass); a total waste management system (handles poop and pee, sending them to the central recycling unit. The MPS units, of course, must be kept in an inhabitable part of the ship, with appropriate environment constantly monitored and adjusted. Ship's AI will be programmed to monitor the basic health status of each livestock animal (ekg, blood gases, respirations) and must cull & jettison deceased animals. Cows live about 20 years. Results: this was a bad idea! Reason being, once your crew wake up, they'll discover that the entire herd of induced coma cattle are long since dead and jettisoned.

Conclusion
Dead tissue presents far fewer challenges as far as storage & maintenance go. Live tissue requires what amounts to 24 hour health management of each livestock animal. In addition, the effort will be wasted since even the optimal lifespan of the livestock animals falls far short of the journey's expected time.

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  • $\begingroup$ Does edible satisfy the conditions stated in my question? Can you back it up with numbers? Does it work the same for all types of dead tissue? Is induced coma the only way to preserve living organisms? $\endgroup$ – Otkin Sep 3 at 9:52
  • $\begingroup$ @Otkin -- Sure. You want food preserved for 200+ years. Your choices are basically dead or alive. Preserving life within an organism over the span of 10 times its typical life span is simply not possible, unless you're willing to use the same tech on your cows and chickens as you do on your crew. Preserving dead tissue solves the problem of not wanting to do the above. There is a tradeoff which you have little choice but to accept. $\endgroup$ – elemtilas Sep 3 at 17:17
  • $\begingroup$ You are too focused on food and livestock. While I indeed need to feed my crew, I need organic matter for other reasons, too. Moreover, I need them to be as close to original as possible. For example, I need most of the DNA and proteins intact and easily accessible for manipulation in many ways. You correctly identify problems associated with keeping animals alive while in a coma, but you ignore all chemical changes to dead tissue. I also realise that this whole topic of keeping organic matter intact for long periods of time is highly underappreciated and people tend to oversimplify things. $\endgroup$ – Otkin Sep 3 at 18:42

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