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CO2 buildup in the lungs triggers the breathing reflex in most mammals, with high levels of CO2 leading to the sensation of asphyxiation. Nitrogen, on the othe

CO2 buildup in the lungs triggers the breathing reflex in most mammals, with high levels of CO2 leading to the sensation of asphyxiation. Nitrogen, on the other hand, is completely imperceptible (at least in humans; I assume the same thing is true for other animals). People have died in nitrogen rich atmospheres because they had no idea they were in a hypoxic environment until they lost consciousness. So why not switch to nitrogen asphyxiation instead? Is it that much more expensive? The quality of meat might be better, since the animals would not be stressed moments before dying.

InCityDreams 4y ago
I have reduced my meat consumption to virtually zero. Is there any proof that a stressed animal gives worse quality meat? Even after cooking it? Could anyone double-blinded tell the difference?
- amalgamated_inc 4y ago
  I'd be surprised if anybody could tell. Natural variation in other factors that impact flavor far more are almost certainly going to be much stronger, e.g. how fatty is the cut of mean, how's the fat distributed, natural variations on muscle fiber, how long was it aged/dried, which piece got more heat from the heat source during cooking..
- deleted 4y ago
  [deleted]
- sofixa 4y ago
  Yep, it results in worse quality meat: https://www.atlasobscura.com/articles/why-scared-animals-taste-worse https://www.atlasobscura.com/articles/why-scared-animals-tas... I thought this was well known - it's the main reason why killing methods are 'stealthy' (the animals don't see them coming) in slaughterhouses.
- Ancapistani 4y ago
  Stressed animals can panic and injure themselves trying to escape, which absolutely means quality issues. > Even after cooking it? Could anyone double-blinded tell the difference? It doesn't matter to the company, because it's apparent when you look at the packaged meat.
Ancapistani 4y ago
AFAIK, slaughterhouses don't use CO2 (carbon dioxide) - they use CO (carbon monoxide). The effect is identical to nitrogen, and doesn't trigger the physiological suffocation response.
- lcnPylGDnU4H9OF 4y ago
  Sounds like this one is different. > We have invested in research to understand which techniques cause the least pain and stress to the animals and to their handlers. For pigs weighing less than 65 pounds, we use either carbon dioxide (CO2), which causes painless loss of consciousness and death, or a device called a nonpenetrating captive bolt gun, which administers a controlled blow to the head without breaking the skin, instantaneously rendering the animal insensible and causing a quick death. For pigs larger than 65 pounds, we use a penetrating captive bolt gun that fires a retractable metal bolt into the brain, resulting in insensibility and death. https://www.smithfieldfoods.com/animal-care https://www.smithfieldfoods.com/animal-care (near the bottom is a section labelled "Humane Euthanasia and Slaughter")
  - Ancapistani 4y ago
    Surely that's a mistake - if not, it's a huge problem. I'm going to reach out to them and ask for clarification, because that statement is entirely inconsistent with reality.
    - Ancapistani 4y ago
      Hmm. I'm doing some digging, and apparently CO2 is used, at least in some context, for a lot of large processors. Here's an example of a product advertising it: https://www.frontmatec.com/en/pork-solutions/unclean-line/stunning/co2-stunning-system# https://www.frontmatec.com/en/pork-solutions/unclean-line/st... Mea culpa. I'll do a bit more digging first, to make sure I understand how it's being used. Just putting an animal into a chamber with a concentrated CO2 atmosphere would be identical to putting a bag over their head - obviously inhumane. Logically, that doesn't make sense to me. If nothing else, the animals would struggle and be very loud, which would panic the rest of the queue. I'll follow up once I know more.
LarryMullins 4y ago
A handful of times I have encountered people with the mistaken belief that CO2 euthanasia is painless because "that's how we kill lab rats" and "that's how the vet put my dog to sleep." They're wrong about CO2 being painless of course, but it seems to be a somewhat common misconception. Also many people get carbon monoxide and carbon dioxide mixed up, adding to the confusion. More education is necessary. Right now a lot of people have no clue that they're wrong.
- tsuujin 4y ago
  I feel like carbon monoxide would be so much more humane too. I used to work a job where we had to vigilantly check for CO because it could kill a whole family without anyone realizing they were in danger. 1200 parts per million is fatal. Pump like 2500 PPM of CO into the chamber to be sure, everything dies, no suffering needed.
- JumpCrisscross 4y ago
  > that's how the vet put my dog to sleep Do vets really do this? My dog was put down with a tranquilliser.
  - LarryMullins 4y ago
    As far as I can tell, euthanizing pets with CO2 is presently contrary to recommendations but used to be common. And CO2 is still often used for euthanizing wild animals.
- puffybuf 4y ago
  We used CO to kill mice in my lab. Concentrated CO, filling the chamber first with it. They would take two breaths and pass out, maybe twitch once or twice, and that was it. If I had to die I’d like to go that way.
2OEH8eoCRo0 4y ago
Cost I'm sure. Nitrogen is slightly lighter than air, carbon dioxide is heavier than air. They are lowered into the CO2 chamber. If it were nitrogen it would need to be redesigned. Why are no startups exploring nitrogen? The world isn't going to go vegan. Cost effective nitrogen gas chambers could reduce a fair amount of animal suffering in a pragmatic way.
- throw_away1525 4y ago
  Air is 30% nitrogen. Air separation (into N2 and O2) is a well understood process, liquid nitrogen is abundant. Lowering them into the chamber, putting them in a chamber and filling it up, it makes no difference. The only reason is that no one cares.
  - shoelessone 4y ago
    I'll admit I just skimmed this article and don't know the source, so happy to be shown the light, but I seriously doubt it's because no one cares. https://www.ri.se/en/what-we-do/projects/replacement-of-carbon-dioxide-for-stunning-purposes-in-pigs https://www.ri.se/en/what-we-do/projects/replacement-of-carb...
    - Ancapistani 4y ago
      I'd say that pretty much everyone involved cares - either about the animal's experience, or about the financial impact. As I said elsewhere, at least in this case those incentives are largely aligned.
  - atmavatar 4y ago
    Air is actually ~78% nitrogen. That merely furthers the point, though. https://en.wikipedia.org/wiki/Atmosphere_of_Earth https://en.wikipedia.org/wiki/Atmosphere_of_Earth
- etrautmann 4y ago
  companies in this business will not change until forced via regulation or consumer preference. It's not like they can advertise or explain more human slaughter methods on the package.
loufe 4y ago
I know the feeling well. I really like carbonated water. At work I take a large 54 floz growler full to drink every half shift. It took me a while, after I started, to realize that I was inhaling concentrated CO2 before actually drinking. I was feeling awful as I went to take a sip. I have a habit now of blowing into the growler to empty it of CO2 after opening the lid, which works perfectly. It felt like you haven't taken a breath for 30 seconds.
oliwarner 4y ago
> So why not switch to nitrogen asphyxiation instead? Is it that much more expensive? Food grade gasses (for brewers, at least) seem to put N2 as much cheaper. And that makes sense, it's aggressively abundant in the atmosphere. Concentrating it feels like it should be easy. But I wonder if there's a safety aspect. If you're handling these gasses, you know if you're in a high CO2 area. Your blood acidity climbs and everything in your body tells you to get to better air. And it's rapid so you still have oxygenated tissues. In a nitrogen environment, you slowly deplete your reserves, faint and die. Maybe they could spike it with an odour like they do methane.

InCityDreams 4y ago

I have reduced my meat consumption to virtually zero. Is there any proof that a stressed animal gives worse quality meat? Even after cooking it? Could anyone double-blinded tell the difference?

amalgamated_inc 4y ago
I'd be surprised if anybody could tell. Natural variation in other factors that impact flavor far more are almost certainly going to be much stronger, e.g. how fatty is the cut of mean, how's the fat distributed, natural variations on muscle fiber, how long was it aged/dried, which piece got more heat from the heat source during cooking..
deleted 4y ago
[deleted]
sofixa 4y ago
Yep, it results in worse quality meat: https://www.atlasobscura.com/articles/why-scared-animals-taste-worse https://www.atlasobscura.com/articles/why-scared-animals-tas... I thought this was well known - it's the main reason why killing methods are 'stealthy' (the animals don't see them coming) in slaughterhouses.
Ancapistani 4y ago
Stressed animals can panic and injure themselves trying to escape, which absolutely means quality issues. > Even after cooking it? Could anyone double-blinded tell the difference? It doesn't matter to the company, because it's apparent when you look at the packaged meat.

Ancapistani 4y ago

AFAIK, slaughterhouses don't use CO2 (carbon dioxide) - they use CO (carbon monoxide). The effect is identical to nitrogen, and doesn't trigger the physiological suffocation response.

lcnPylGDnU4H9OF 4y ago
Sounds like this one is different. > We have invested in research to understand which techniques cause the least pain and stress to the animals and to their handlers. For pigs weighing less than 65 pounds, we use either carbon dioxide (CO2), which causes painless loss of consciousness and death, or a device called a nonpenetrating captive bolt gun, which administers a controlled blow to the head without breaking the skin, instantaneously rendering the animal insensible and causing a quick death. For pigs larger than 65 pounds, we use a penetrating captive bolt gun that fires a retractable metal bolt into the brain, resulting in insensibility and death. https://www.smithfieldfoods.com/animal-care https://www.smithfieldfoods.com/animal-care (near the bottom is a section labelled "Humane Euthanasia and Slaughter")
- Ancapistani 4y ago
  Surely that's a mistake - if not, it's a huge problem. I'm going to reach out to them and ask for clarification, because that statement is entirely inconsistent with reality.
  - Ancapistani 4y ago
    Hmm. I'm doing some digging, and apparently CO2 is used, at least in some context, for a lot of large processors. Here's an example of a product advertising it: https://www.frontmatec.com/en/pork-solutions/unclean-line/stunning/co2-stunning-system# https://www.frontmatec.com/en/pork-solutions/unclean-line/st... Mea culpa. I'll do a bit more digging first, to make sure I understand how it's being used. Just putting an animal into a chamber with a concentrated CO2 atmosphere would be identical to putting a bag over their head - obviously inhumane. Logically, that doesn't make sense to me. If nothing else, the animals would struggle and be very loud, which would panic the rest of the queue. I'll follow up once I know more.

LarryMullins 4y ago

A handful of times I have encountered people with the mistaken belief that CO2 euthanasia is painless because "that's how we kill lab rats" and "that's how the vet put my dog to sleep." They're wrong about CO2 being painless of course, but it seems to be a somewhat common misconception. Also many people get carbon monoxide and carbon dioxide mixed up, adding to the confusion. More education is necessary. Right now a lot of people have no clue that they're wrong.

tsuujin 4y ago
I feel like carbon monoxide would be so much more humane too. I used to work a job where we had to vigilantly check for CO because it could kill a whole family without anyone realizing they were in danger. 1200 parts per million is fatal. Pump like 2500 PPM of CO into the chamber to be sure, everything dies, no suffering needed.
JumpCrisscross 4y ago
> that's how the vet put my dog to sleep Do vets really do this? My dog was put down with a tranquilliser.
- LarryMullins 4y ago
  As far as I can tell, euthanizing pets with CO2 is presently contrary to recommendations but used to be common. And CO2 is still often used for euthanizing wild animals.
puffybuf 4y ago
We used CO to kill mice in my lab. Concentrated CO, filling the chamber first with it. They would take two breaths and pass out, maybe twitch once or twice, and that was it. If I had to die I’d like to go that way.

2OEH8eoCRo0 4y ago

Cost I'm sure. Nitrogen is slightly lighter than air, carbon dioxide is heavier than air. They are lowered into the CO2 chamber. If it were nitrogen it would need to be redesigned. Why are no startups exploring nitrogen? The world isn't going to go vegan. Cost effective nitrogen gas chambers could reduce a fair amount of animal suffering in a pragmatic way.

throw_away1525 4y ago
Air is 30% nitrogen. Air separation (into N2 and O2) is a well understood process, liquid nitrogen is abundant. Lowering them into the chamber, putting them in a chamber and filling it up, it makes no difference. The only reason is that no one cares.
- shoelessone 4y ago
  I'll admit I just skimmed this article and don't know the source, so happy to be shown the light, but I seriously doubt it's because no one cares. https://www.ri.se/en/what-we-do/projects/replacement-of-carbon-dioxide-for-stunning-purposes-in-pigs https://www.ri.se/en/what-we-do/projects/replacement-of-carb...
  - Ancapistani 4y ago
    I'd say that pretty much everyone involved cares - either about the animal's experience, or about the financial impact. As I said elsewhere, at least in this case those incentives are largely aligned.
- atmavatar 4y ago
  Air is actually ~78% nitrogen. That merely furthers the point, though. https://en.wikipedia.org/wiki/Atmosphere_of_Earth https://en.wikipedia.org/wiki/Atmosphere_of_Earth
etrautmann 4y ago
companies in this business will not change until forced via regulation or consumer preference. It's not like they can advertise or explain more human slaughter methods on the package.

loufe 4y ago

I know the feeling well. I really like carbonated water. At work I take a large 54 floz growler full to drink every half shift. It took me a while, after I started, to realize that I was inhaling concentrated CO2 before actually drinking. I was feeling awful as I went to take a sip. I have a habit now of blowing into the growler to empty it of CO2 after opening the lid, which works perfectly. It felt like you haven't taken a breath for 30 seconds.

oliwarner 4y ago

> So why not switch to nitrogen asphyxiation instead? Is it that much more expensive? Food grade gasses (for brewers, at least) seem to put N2 as much cheaper. And that makes sense, it's aggressively abundant in the atmosphere. Concentrating it feels like it should be easy. But I wonder if there's a safety aspect. If you're handling these gasses, you know if you're in a high CO2 area. Your blood acidity climbs and everything in your body tells you to get to better air. And it's rapid so you still have oxygenated tissues. In a nitrogen environment, you slowly deplete your reserves, faint and die. Maybe they could spike it with an odour like they do methane.