Carcasses ‘going off’ , ideas?

[wildfowler.250]

Thanks folks, just thinking about it:

It had been a day of torrential rain. Coat probably still wet.

Chest shot deer - quite a lot of blood/bruising around the chest area - probably ideal of bacteria as well.

I think going forward I’ll make sure the coat is completely dry as I’ve never used a towel to make sure the coat is dry first. I’ll go back to 5 days and get a gauge of some description to check temp/humidity.

The more I think about it it’s probably a moisture issue. Thanks!

 

[Freeforester]

Right folks, I’ve had this happen a couple of times in the past year now and it’s driving me mad.

So last time, I’d rinsed the blood out of the chest cavity, hung the roe for a week and when I went to butcher it, it was clearly off - assumed the damp and never rinsed again since then.

Had another deer recently. Chest shot. Cleaned at the time. No real contamination. Bullet or bone had nicked the osophagus within the chest cavity but this was actually completely contained. Fairly spotless going into the roe sack - I was pleased with it. Hung at 1C for 7 days.

Today, there was a greyness to the neck area and a tiny bit of smell. There was also a bit of of an off look around the pelvic canal area and over the tenderloins.


Now, the game birds I hang for a week,(usually I try and clean sooner) are fine. I don’t think it’s a temp issue but that would be easy to check. It is a proper chiller, 2 years old maybe, which goes from 1C up to 4C then cools back down to 1C again.


Am I expecting too much? Should I be butchering after max of 5 days? I thought some folk would hang for 2 weeks if they wanted.

Is it tiny bits of dirt from the field? It was honestly very clean.


I’m pretty disheartened because it was a clean carcass when gutted. Went into a roe sack so minimal dirt from shot to car boot. The back legs and loin looked ‘okay’ but you can’t eat in good conscience when other parts smell a bit off.


Any suggestions? If the rumen was burst or something then sure. But anything over 5 days hanging seems to be roulette. I don’t think I can realistically set it cooler than 1C.

How big is the chill or fridge you use, and how clean is it (- as in when might it last have been thoroughly disinfected)? Is there a fan within the chill circulating the cold air? Many home setups don’t have sufficient circulation of air or insufficient internal volume to properly hang for any length of time without spoilage occurring.

Regarding water for rinsing - not all water supplies are the same; I used to buy in carcasss from time to time from the local FCS larder, and they were always the first to go off, which I put down to their town water supply ( you should have seen the reaction of decent cask whisky when town tap water was added - it fizzed and a scum appeared on the top of the dram in the glass). On a private water supply here, with minimal chemical intervention, I routinely rinse all carcasses yet suffer no ill effects, and a red Deer carcass could
be hung for a couple of weeks without issue - NB in my experience this has NO bearing on strength or depth of flavour - that comes from the carcass, what the animal had eaten, whether it had been harassed prior to being culled and how it was handled thereafter - but it certainly improves tenderness of the meat as the enzymes work on breaking down the tougher components of the flesh. For roe deer they would only begin to show any bloom after about 12-14 days.

The two I took this afternoon are hanging in the outbuilding but aren’t going to be artificially chilled, it’s between 1-3°C here, with forecast showing this for the coming week (sleety snow at 1300 when out), and again IME better venison comes from naturally cooled (unforced) hanging, in plenty of space for good air circulation.

 

[pendle]

How big is the chill or fridge you use, and how clean is it (- as in when might it last have been thoroughly disinfected)? Is there a fan within the chill circulating the cold air? Many home setups don’t have sufficient circulation of air or insufficient internal volume to properly hang for any length of time without spoilage occurring.

Regarding water for rinsing - not all water supplies are the same; I used to buy in carcasss from time to time from the local FCS larder, and they were always the first to go off, which I put down to their town water supply ( you should have seen the reaction of decent cask whisky when town tap water was added - it fizzed and a scum appeared on the top of the dram in the glass). On a private water supply here, with minimal chemical intervention, I routinely rinse all carcasses yet suffer no ill effects, and a red Deer carcass could
be hung for a couple of weeks without issue - NB in my experience this has NO bearing on strength or depth of flavour - that comes from the carcass, what the animal had eaten, whether it had been harassed prior to being culled and how it was handled thereafter - but it certainly improves tenderness of the meat as the enzymes work on breaking down the tougher components of the flesh. For roe deer they would only begin to show any bloom after about 12-14 days.

The two I took this afternoon are hanging in the outbuilding but aren’t going to be artificially chilled, it’s between 1-3°C here, with forecast showing this for the coming week (sleety snow at 1300 when out), and again IME better venison comes from naturally cooled (unforced) hanging, in plenty of space for good air circulation.

I was just going to ask how often the chiller is cleaned. If there are mould spores on the carcass the will be transferred to the sides of the chiller by the fan.
I clean mine but always leave the door slightly open when not in use. For air flow

 

[Mickeydredd]

It's likely not the chiller,"Key also is getting the animal cool quickly. I am not convinced that shooting, gralloching, loading into a roesack whilst warm and carrying it to the car then driving home is good for the venison. If you can let it cool before transport so much the better."
How far are you travelling from shot to LARDER / HOME?

That was my thinking, the carcase has heated up rather than cooling down on the journey before the chiller.

 

[Mr. Gain]

That was my thinking, the carcase has heated up rather than cooling down on the journey before the chiller.

This would be reasonable, but one would expect most carcasses -at least outside the true winter months- to be thus affected if the journey from stalking ground to chiller is a constant.

 

[Mickeydredd]

This would be reasonable, but one would expect most carcasses -at least outside the true winter months- to be thus affected if the journey from stalking ground to chiller is a constant.

I’ve noticed that my canopy on the Hilux seems to hold in heat so I usually try to get my deer in the syndicate ground chiller before transporting.
I’m actually getting an extractor fitted to try to help with the issue.

 

[Heym SR20]

I like carcasses to be dry and part of the aging process is actually to allow carcass to loose moisture. (See HFW The Meat Book). I much prefer to get the skin off, especially if its mucky, covered in **** and poo (as in rutting stag) and let the carcasses hang skinless. It is after all what butchers do with farmed animals. I appreciate that legally we have to sell in skin, but for your own consumption, or if you are licensed to sell direct, skins off whilst carcass is still warm makes life so much easier.

Recently I have needed to carry out a few roe. Given that I have not had a lot of strength (thanks LC) I have taken to skinning in field and leaving the skins for the critters and to return nutrients for rewilding. Skin a warm carcass is so much easier - they just pull off. Hang the carcass to cool whilst you clean up and catch your breath. Into a game bag and into the pack for carry out, but out of bag and into a clean carcass tray for drive home.

Leaving skin, lower legs etc saves quite a bit of weight. Taking the meat of the carcass even more.

 

[Eric the Red]

Really interesting thread - thank you. Does anyone run a dehumidifier in their chiller - or just rely on circulation? Def looking into these aspects in more detail - either a fan, and or a dehumidifier of some sort

 

[Freeforester]

I like carcasses to be dry and part of the aging process is actually to allow carcass to loose moisture. (See HFW The Meat Book). I much prefer to get the skin off, especially if its mucky, covered in **** and poo (as in rutting stag) and let the carcasses hang skinless. It is after all what butchers do with farmed animals. I appreciate that legally we have to sell in skin, but for your own consumption, or if you are licensed to sell direct, skins off whilst carcass is still warm makes life so much easier.

Recently I have needed to carry out a few roe. Given that I have not had a lot of strength (thanks LC) I have taken to skinning in field and leaving the skins for the critters and to return nutrients for rewilding. Skin a warm carcass is so much easier - they just pull off. Hang the carcass to cool whilst you clean up and catch your breath. Into a game bag and into the pack for carry out, but out of bag and into a clean carcass tray for drive home.

Leaving skin, lower legs etc saves quite a bit of weight. Taking the meat of the carcass even more.

Freshly skinned venison thereafter hung, from a rutting stag… I take it you aren’t in the venison
selling business then, or weren’t for very long?

Out of interest, how long do you typically thereafter hang your stuff before cutting it up?

 

[pendle]

Really interesting thread - thank you. Does anyone run a dehumidifier in their chiller - or just rely on circulation? Def looking into these aspects in more detail - either a fan, and or a dehumidifier of some sort

I have thought of the little dehumidifier pots
I will try one next time I have a carcass for myself. I try to get sold what I have within two days. As SWHO is complaining about the electric bill because of the return I get for a single roe . Most are sold and dropped off on the way home

 

[Dunwaters]

Thanks folks, just thinking about it:

It had been a day of torrential rain. Coat probably still wet.

Wet on the outside of the carcass doesn’t have too much impact. Neither does hanging in or out of the skin, but getting the skin off is easier with a warm carcass

Chest shot deer - quite a lot of blood/bruising around the chest area - probably ideal of bacteria as well.

Bingo!
This is the most likely culprit for initiating early decay and a deer hung in the skin is difficult to assess for shot damage and contamination.
Skin a body shot animal before you hang it and be ruthless rejecting or investigating anything that looks bruised. Check out the layer between the shoulders and the ribs, you’ll often find a pocket of gut content and bloodshot tissue sucked along the wound channel, clean it out.
Regardless of how careful you are, a badly shot or contaminated carcass wont hold as long as a clean one.

I think going forward I’ll make sure the coat is completely dry as I’ve never used a towel to make sure the coat is dry first. I’ll go back to 5 days and get a gauge of some description to check temp/humidity.

The more I think about it it’s probably a moisture issue. Thanks!

It could be, but I’d be far more suspicious of the shot damage, you can usually see excessive moisture condensing on the surface. If the exposed meat is clean and dry and you are still getting decomposition in 4 or 5 days, damp is probably not the problem.

 

[Heym SR20]

Freshly skinned venison thereafter hung, from a rutting stag… I take it you aren’t in the venison
selling business then, or weren’t for very long?

Out of interest, how long do you typically thereafter hang your stuff before cutting it up?

No I am not currently in the venison selling business. I have in past culled on estates that were selling venison directly to consumers as well as to dealers.

All my venison goes into my own freezer or that of the landowners whose deer I manage.

I typically let it hang for a couple of days. In warmer weather I cut roe into quarters and let age in the fridge for a couple of days.

You will also note that I did comment that if you are in venison selling business you need to leave skins on.

 

[Heym SR20]

Wet on the outside of the carcass doesn’t have too much impact. Neither does hanging in or out of the skin, but getting the skin off is easier with a warm carcass

Bingo!
This is the most likely culprit for initiating early decay and a deer hung in the skin is difficult to assess for damage and contamination.
Skin a body shot animal before you hang it and be ruthless rejecting or investigating anything that looks bruised. Check out the layer between the shoulders and the ribs, you’ll often find a pocket of gut content and bloodshot tissue sucked along the wound channel, clean it out.
Regardless of how careful you are, a badly shot or contaminated carcass wont hold as long as a clean one.

I have watched on the butchers working on driven hunts in Germany. On such hunts all the deer and pigs are recovered to the larder still with guts in. Mostly temperature is well below freezing. The butchers are fully qualified including all the veterinary checks.

The skins are left on, but they do cut all the blood shot bits around the entry and exit wounds, including whole shoulders etc if required.

 

[geoffw]

Lots of great points here, to which I would add the use of chest spreaders- allows better air circulation inside the chest cavity and through the pelvis, keeping moisture wicked away.

 

[finnbear270]

I have watched on the butchers working on driven hunts in Germany. On such hunts all the deer and pigs are recovered to the larder still with guts in. Mostly temperature is well below freezing. The butchers are fully qualified including all the veterinary checks.

The skins are left on, but they do cut all the blood shot bits around the entry and exit wounds, including whole shoulders etc if required.

One butcher in a row of eight.
Notice the hose in left hand.

 

[Heym SR20]

View attachment 396117 One butcher in a row of eight.
Notice the hose in left hand.

Yup. They hose everything out using plenty of fresh cold water. I have noticed with boar that they wash them down thoroughly before they even start opening them up.

 

[finnbear270]

Yup. They hose everything out using plenty of fresh cold water.

I forgot to mention, as you state temps below freezing .... the butchers were enveloped in a cloud of steam from hot guts.
This was at the time before the worries of Boar borne disease, and us being asked to open up shot Boar for blood and tissue samples at shot site.

 

[75]

Does anyone run a dehumidifier in their chiller - or just rely on circulation?

I have done, yes. I've done a lot of research into this area but focussed on monobloc chillers. Sorry - long post so skip this if you're not interested in chiller humidity or how monoblocs work!

It came about because I lost a red carcass to mould. It was around the 10-12 day mark and temp had been low and consistent and the carcass clean and dry when it went in so I set about trying to find out what was wrong. First step was to install a temp logger - which also tracked relative humidity and opened up a whole world of humidity pain!! My temperatures were very consistent but the humidity gradually rose with each cooling cycle until it sat around 95%-98%. Anything above 80% will promote mould growth apparently. I had lots of fridge engineers out (including Sikadog) and spent a fortune on chasing the "issue". Everyone who came out said the same: "Everything is working fine but it shouldn't do that, chillers strip moisture". Had it re-gassed and various other things. Temp was always very stable and consistent but humidity did the same - rose when you turned on the chiller, even when the coldroom was empty.

So my interim solution was to put a small dehumidified in there. You need a desiccant type that will run down to about 1C. External drain piped out to a bucket. It worked and it would hold the humidity nicely around the 65-70% mark. But they do add a bit of heat into the coldroom so it will be working against the chiller and using more energy.

@VSS will confirm that the experts reckon about 75% RH is perfect for an in skin carcass, but I'd rather RH was lower than higher, especially if there are a few in there or fur was wet etc. Note though - RH is relative so air at 50% RH at 1 degree holds less moisture than air at 50% RH and 3%. Temp plays an important part in all this so don't get hung up on chasing low RH and low temp.

So back to the root cause. I gradually started to understand how monoblocs work and came to the following conclusion - this is my idiots guide in terms I understand, so if you're a technical refrigeration expert look away now!

The monobloc comprises of two key parts. Outside the coldroom is a compressor, inside the coldroom is a condenser - the fins. Compressor runs on a cooling cycle and chills a gas which is circulated around the condenser, turning the fins cold (usually below freezing even if coldroom is running at c.2-3C). There is a separate fan above / below the condenser which circulates air from the coldroom over the fins, chilling this internal air. It's basically a heat exchanger. During this cooling cycle when the fins are below freezing, moisture from the coldroom air condenses and then freezes onto the fins, giving a coating of frost. During this phase, moisture is removed from the air and RH drops. All good...

What is supposed happen is that once the thermostat senses coldroom air has reached the desired temp, the cooling cycle ends; the compressor cuts out. The internal fins warm slightly, the frost melts and drips off into a tray below the fins and runs out an evaporator drain. This is usually to an external pipe and needs plumbing into bucket / drain. But, and this is a very big but!! Lots of monoblocs run with the internal fan on constant - good idea, it keeps a constant temp in the coldroom and keeps air moving. However, as the frost is melting, is simply gets evaporated off the fins and back into the air within the coldroom. It never gets a chance to drip off and run out the evaporator drain. RH climbs back up. Each cycle RH drops, pulls in a fraction more moisture (from a tiny gap on the door seal or out of the carcass etc) then blows it back into the coldroom so the RH climbs a fraction more overall. This still happens with a empty coldroom and the door and all joints taped. I've tried it!

However, lots of monoblocs come with the option to have the internal fan only running during a cooling cycle. This was the default setting on a new Rivacold unit I installed recently and was how I used to run my old chiller. This option allows the moisture to drain out of the condensate drain without being evaporated back into the coldroom atmosphere. Here is a logger of RH. Same chiller, same internal and external conditions. The only thing I changed was the setting on the control panel from fan only on when compressor is running to fan on permanent:



So my solution now is that I run my monobloc with the internal fan only on during cooling cycles and a separate, compact desk fan fixed in the top corner out the way which circulates air within the coldroom but has no impact on humidity.

 

[75]

I should add, very little understanding of humidity in coldrooms. It’s just not something folk really look at in the catering industry etc. All the comments along the lines of “it shouldn’t really do that” are theoretical and there is little real world experience / understanding.

 

[Moray Outfitting]

There is also the quality of the water that was used to clean out. Many private water supplies will have bacteria that can do this to a carcase. I have seen us having to put steralizing tablets into a bucket of water before cleaning down. All these places had private springs. J