Putting Meat in Compost Heaps: Reasons Why?

[sophiecentaur]

Why do 'they' say that you shouldn't put meat in compost heaps?
Is it just because of encouraging rats and things or something to do with the chemistry of the processes?

 

[Evo]

If you are interested in trying it, this is a gardening forum I use occasionally.

http://forums2.gardenweb.com/forums/load/soil/msg111729206409.html?12

 

[marcusl]

I believe it has to do with pests, as you said. It must also change the nutrient content of the compost, maybe not in good ways (don't fats break into aldehydes and other compounds? Need help from a biochemist.)

Here are instructions on composting an entire (dead) cow:
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Adult cattle should be composted using the following method:-

1.In the manure stockpile area, or approved composting site, place a layer of dry organic matter 30 – 45 centimetres deep on the ground over an area slightly larger than the carcase. Straw, sawdust or hay are all suitable.

2.Place the dead animal on the bed and cover with another layer of the dry organic material to a depth of 30 centimetres.

3. Cover the whole lot with 60 centimetres depth of semi-dry organic material such as feedlot pen manure, stockpiled manure, or silage. This layer needs to be at least 60 centimetres deep to contain odours and exclude scavengers.

4. Allow the pile to “work” for 20 days undisturbed. Internal temperatures should reach between 65 – 75oC.

5. After 20 days, or when the internal temperature falls below 60oC, turn the pile and expose the carcase. Cover the carcase again with 30 centimetres of dry organic material and 60 centimetres of semi-dry material.

6. Allow the pile to “work” for another 20 days undisturbed. Internal temperatures should reach 70oC and then slowly decrease. After the 40 days only large bones and some hair will remain.

The composted carcase can then be incorporated with manure or solid wastes for spreading on land.
------------------------
From
http://www.epa.sa.gov.au/pdfs/cattle.pdf"

 

[turbo]

Rotting meat stinks really bad, and it attracts rats. Other than that, it can be composted. Native Americans used to use fish as fertilizer, after all.

 

[Studiot]

Yes I agree if you frequently put meat scraps, cooked or raw, onto your compost heap you will soon have a rat population.

It is often suggested however, that a compost heap benefits from 'animal nitrogen'. Sources include nail clippings, hair, wool or the vacuum cleanings of wool carpets and of course animal urine.

 

[hypatia]

It also may encourage bacterial and fungal growth that could be undesirable. And yea, it stinks really bad.

 

[sophiecentaur]

Thanks. That all makes sense. I have a plastic 'dalek' in my small garden and it works very well with all our veg waste and peelings. It has a massive population of worms and other invertebrates which cope well with large vegatable items and I reckon the slugs and beetles would deal with small lumps of meat before they would be acted on by microorganisms. I was considering building a brick unit which would be rat proof and, having dealt with that issue, the breaking down of quite small quantities of animal waste would not be too much of a problem. I'm talking about the occasional well- picked chicken or fish carcass and nothing bigger.

 

[turbo]

Thanks. That all makes sense. I have a plastic 'dalek' in my small garden and it works very well with all our veg waste and peelings. It has a massive population of worms and other invertebrates which cope well with large vegatable items and I reckon the slugs and beetles would deal with small lumps of meat before they would be acted on by microorganisms. I was considering building a brick unit which would be rat proof and, having dealt with that issue, the breaking down of quite small quantities of animal waste would not be too much of a problem. I'm talking about the occasional well- picked chicken or fish carcass and nothing bigger.

That might work OK. You may want to consider finding a way to mechanically break down the bones, since they will degrade much more slowly than vegetable matter. Bone meal is a good source of phosphorus and a fair source of calcium, so it would be good soil amendment. It's also slow-release, unlike "hotter" inorganic chemical fertilizers.

 

[Evo]

That might work OK. You may want to consider finding a way to mechanically break down the bones, since they will degrade much more slowly than vegetable matter. Bone meal is a good source of phosphorus and a fair source of calcium, so it would be good soil amendment. It's also slow-release, unlike "hotter" inorganic chemical fertilizers.

Bone meal, blood meal, all good stuff for different needs.

 

[bobze]

Thanks. That all makes sense. I have a plastic 'dalek' in my small garden and it works very well with all our veg waste and peelings. It has a massive population of worms and other invertebrates which cope well with large vegatable items and I reckon the slugs and beetles would deal with small lumps of meat before they would be acted on by microorganisms. I was considering building a brick unit which would be rat proof and, having dealt with that issue, the breaking down of quite small quantities of animal waste would not be too much of a problem. I'm talking about the occasional well- picked chicken or fish carcass and nothing bigger.

As others pointed out the smell can be undesirable and that smell (rotting meat) is undesirable to us for good reason. Evolutionary speaking; we loath the smell because it is a sign that the "food" may contain potentially harmful pathogens that our bodies can't deal with.

I think this is probably a reason the recommendation exists, that you could potentially foster the growth of dangerous pathogens and when working with the compost at a later time or improperly washing veggies grown in said compost, could make you or those you prepare food for spend a lot of extra time in the john, if you know what I mean.

Chickens and fish are both "notorious" for harboring potential human pathogens even in "sealed" meat (that below the surface), which is why you can't eat rare chicken and why fish more than a few hours old needs cooked. For safety, I'd pop any raw potential meat compost in the microwave for 5 minutes or so on high. While this won't sterilize the meat, it should be enough to kill any potential bacterial pathogens (at least of the non-spore forming variety). So long as you don't mind the smell then, I'd say your in business.

If its been cooked already, we'd hope it was devoid of pathogens (considering you've eaten it) and should be okay. Just be smart about it. If Grandma's meatloaf gave everyone at dinner the runs, you probably should skip composting that!

Also, as others pointed out, "vermin" can be a problem (as they too can carry undesirable bugs with them). I'd worry less about the rats and more about the raccoons, coyotes and foxes (if they are present in your area and raccoons and coyotes are just about every, even in cities). I think a good, sturdy composting container (such as the brick one your talking about) would be a good start for dealing with them. You don't want your yard to become the raccoon hang out, especially if you have smaller pets or children out and about. Keeping them and their poo out is a must, considering they can carry non-typical pathogens (like round worms) which can be a little harder to sanitize from raw veggies than a simple wash and which can be even harder to sanitize from yourself if you get infected!

 

[hypatia]

If you want to make it rat proof, you will have to make a rat wall, at least 18 inches into the ground, and at least 4 inches thick. Made of cement or stone.

 

[sophiecentaur]

Hellfire, this sounds like a major defence issue: WW2 bunker stuff.
I was going to put it on a concrete floor with some v. small holes for drainage. I think the rats would blunt their their teeth on that! If I hear a Kango going in the middle of the night then I'll know who's at it! I planned an aluminium shutter at the bottom sliding in a channel.
I guess some thermal insulation could help get the internal temperature up nice and high.
I have to admit that it's a bit of a way down my list of jobs to do, though.

 

[Studiot]

I had a (one) rat problem a couple of years backalong.

I borrowed a weldmesh squirrel trap from friend and set it where I knew the blighter ran in the back garden.

In three months I caught 3 squirrels, 6 blackbirds, 2 pigeons and one badger, but no rat. I had to let them all out.

Then one afternoon there was the most appalling squealing from the trap. I had finally got my rat.

In about half an hour (I didn't attend to the trap immediately) the rat managed to chew and kick through the welded steel mesh enough to escape. The cage was well bent. Sorry I don't have a photo.

 

[bobze]

Hellfire, this sounds like a major defence issue: WW2 bunker stuff.
I was going to put it on a concrete floor with some v. small holes for drainage. I think the rats would blunt their their teeth on that! If I hear a Kango going in the middle of the night then I'll know who's at it! I planned an aluminium shutter at the bottom sliding in a channel.
I guess some thermal insulation could help get the internal temperature up nice and high.
I have to admit that it's a bit of a way down my list of jobs to do, though.

Rats can easily chew through brick, steel pipes even. So if they want in, they'll get in. I'd use the brick for a deterrent for larger visitors.

Where do you live sophiecentaur?

 

[sophiecentaur]

South coast UK.
Plenty of rats around here. They wait on the edge of the School field until the kids go back in after break time. Loads to eat there.