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Comment by StavrosK | Hacker News Reader

Did prions survive cooking? I'd have thought cooking the beef would have killed them.

If you took affected neural tissue and burned it to ash on a wood fire, there remains (although low) infective potential but probably only if you were trying in a lab. It takes 1000 C incineration to defeat infectivity and even then they’re still detectable.

Composting so the proteins are broken down biologically is also an alternative.

No amount of cooking prions that leave anything you want to eat makes infected material safe.

Agree that cooking is not an option.

You can actually get that 1000C down to 600C if you also soak the tissue in acid prior to burning.

That pretty much describes how I cook my steaks, a nice H2SO4 marinade followed by ten minutes in a bonfire

As long as you don't put ketchup on it.

I’m not so sure about the composting - the breakdown of organic material (well, protein in this case) in soils is largely brought about by proteases and proteases are largely ineffective

I thought 200C for an hour was enough.

Prions are incredible hard to destroy.

To quote from Wikipedia:

`Prion aggregates are stable, and this structural stability means that prions are resistant to denaturation by chemical and physical agents: they cannot be destroyed by ordinary disinfection or cooking.`

Oooof...

Iirc hospitals that treat patients with prion diseases incinerate all materials that contact the patients. I don't know how they sanitize the rooms but it can't be cheap or eco friendly.

Destroying prions is eco friendly.

Humans need a non toxic environment. Plants, and life in general, will find a way. With, and without, us.

Chemical agents which cause protein-crosslinking would be the preferred method - you can broadly make every side-group reactive and cause them all to stitch together with anything else organic, which tends to inactivate them (makes them a big blob which can't do much).

But it's nasty stuff to work with, since it also happily does tons of damage to the proteins making up the humans applying it.

Do you have an example of such a chemical being used to effectively remediate prion contaminated environments?

Apparently not: I was thinking glutaraldehyde which is used for cleaning in hospitals but reading up the advice for prions is explicitly opposed to cross-linking agents.

Which makes sense I guess but it's also scary.

You raised my hopes and dashed them exquisitely.

Until we have better, cheaper, and less error prone methods of remediating prion diseases they're the #1 fear on my biological apocalypse list.

That's not good.

Are prions contagious through contact or only eating?

Sterrad sterilization machines, which use a hydrogen peroxide gas plasma, have been shown to be very effective against CJD (mad cow) and other prion diseases. However they are very expensive, and almost 20 years after their launch there are only 20k systems installed world wide.

A plasma of H2O2 sounds like the definition of a reactive environment…

That's not entirely true. They know that bleach can be used against CWD for surface decontamination. I would call a 50/50 bleach water solution quite common for disinfectant.

https://www.nih.gov/news-events/news-releases/household-blea...

Yes, prions can survive cooking. Emphasis mine:

> 134 °C (273 °F) for 18 minutes in a pressurized steam autoclave has been found to be somewhat effective in deactivating the agent of disease

https://en.wikipedia.org/wiki/Prion#Sterilization

Yes and they can pass on to other patients from surgical tools

https://www.scientificamerican.com/article/surgical-exposure...

Yes they do. From wikipedia : Prion aggregates are stable, and this structural stability means that prions are resistant to denaturation by chemical and physical agents: they cannot be destroyed by ordinary disinfection or cooking. This makes disposal and containment of these particles difficult.

Yes they do, unfortunately. And there are recently discovered cases of chronic wasting disease (CWD) in elk, deer and moose worldwide. I hope it doesn't pass to humans. For the time being I'll refrain from eating game.

I would be more worried about beef. There has been no evidence of CWD jumping to humans, but there has been for BSE.

Also, do you have a link for the distribution? My understanding is that it is spread over a large geographic area, but that it's found in smaller clumps.

There are several maps and studies, depending on which country you're interested in. The best one that I've found was for Norway. Needless to say, it's spreading over an increasingly larger area every year.

Yes, BSE is also worrying, but beef that you buy at supermarkets is also checked more thoroughly compared to game meat. I'd worry more about restaurants and their suppliers.

The only way to destroy prions is to destroy all protein in the material. What's left wouldn't be worth eating.

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