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Kitchen Notes: Freezing Meats
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Trillian
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PostPosted: Thu Dec 08, 2005 7:57 am    Post subject: Reply with quote

Re the benefits of freezing. There are 3 components to food spoilage, (1)decomposition by micobials, (2) decomposition by chemistry (eg saponification), (3)decomposition by physical deterioration.

Freezing only prevents food degredation from spoilage due to microbial activity. Fats & oils will still become tainted with rancidity (#2) at -18C/0F ... eventually; and as a frozen strawberry (#3) will tell you there are some irreversible side effects to freezing.
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PostPosted: Thu Dec 08, 2005 7:57 am    Post subject: Reply with quote

I conduct research on rabbit pancreas we extract ribosomes (large molecules) from them. I found that if I store the pancreas (meat) at -20 deg Celius, I get freezer burn. But if I store the meat at -80 deg Celius, there is not freezer burn!

So for you geeks out there with available liquid Nitrogen this is a great way to keep meats for a LONG time.
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PostPosted: Thu Dec 08, 2005 7:58 am    Post subject: Reply with quote

The -20degC vs -80degC storage is valid, but here are a couple points:

1) The meat will freeze faster (probably almost instantly) when you dunk it in LN2 than in a (presumably an air chamber) -20C unit. Rapid freezing will result in a much more even freeze.

2) Presumably you put the stuff in a bag before freezing it either way. Dunking it in LN2 is going to force most of the air to one side of the bag and thus expose less surface area of the meat to the air, thus less area for the ice to sublimate.

3) The vapor pressure of water at -80degC is a LOT less than at -20degC or -5degC (approximately the temp of most consumer freezers) thus there will be less sublimation going on at the lower temperatures by default. This is the most beneficial thing about the low temp storage.

4) Rapidly freezing tissue will rupture the cells. Slow freezing does much less damage. I'm fairly sure that you don't just dunk it in LN2 to freeze it though -- usually putting things in low temp storage is a staged process -- ice bath or fridge, freezer, and then directly to cold storage or staged into to cold storage (depending on what chemicals other than water are in what you are storing). Anyway, I wouldn't advise dunking an expensive cut of meat into liquid nitrogen to preserve it. At least leave it in the freezer overnight first.
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eadmund
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PostPosted: Thu Dec 08, 2005 7:58 am    Post subject: Reply with quote

Re. Thawing in the Sink

I wouldn't thaw it in the sink, as sinks are full of nasty organisms, but thawing on the counter all day should be fine. A few hours sitting on the sideboard won't ruin the meat--remember that many meats are hung for a few days anyway. Besides, there just isn't enough time for toxins to accumulate, and cooking will kill off any micro-organisms.

As a last defense, one's immune system is pretty trustworthy:-)
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PostPosted: Thu Dec 08, 2005 7:58 am    Post subject: Reply with quote

Don't get all stressed out over thawed meat sitting at room temperature for a few hours. As George Carlin points out, your immune system needs germs to practice on. No antigens, no antibodies.
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PostPosted: Thu Dec 08, 2005 7:58 am    Post subject: Reply with quote

also the guy says to leave the meat in the ziplock bag when it thaws. i'm guessing if you cough on the meat or somehow horribly contaminate it before freezing, it's going to get festy pretty quick when it thaws, but if there's few contaminants to begin with it should be fine in the bag for a few hours. but where i live it's cold.
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PostPosted: Thu Dec 08, 2005 7:59 am    Post subject: Reply with quote

This is in response to the question about freezing fish. One thing to bear in mind when you freeze seafood is it has a much higher water content than most meats. Because of this there are really only two ways to effectively freeze fish and maintain most of its flavor and texture. Keep in mind that frozen fish will never be a match for fresh. To me it's like the difference between fresh tuna and its distant canned cousin. Personally I do not eat any frozen seafood unless I have no other option, but that is my own bit of snobbery.

The first freezing method is to do what your friend did, by placing the fish in direct contact with liquid and freezing the fish in a block of ice. This gentle method of freezing gives the best-tasting product and it is the only freezing method I recommend anyone use at home. You may have some limited success with plastic bags, foil or plastic wrap, but this method is pretty much guaranteed. The key is to make sure as much of the flesh as possible is surrounded by liquid.

The second method is called IQF, or Individually Quick Frozen, and is a commercial process that is often employed while fishing boats are at sea. I'm not sure of the particulars of the process, but the results speak for themselves. About 90% of the shrimp sold in the US is IQF, and it is also used for orange roughy, swordfish, halibut, sea bass, and a number of other species.

Hope that helps,

-- Charles (fishmonger turned software engineer)
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itallushrt
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PostPosted: Thu Dec 08, 2005 7:59 am    Post subject: Reply with quote

Re. Thawing in the Sink

I wouldn't thaw it in the sink, as sinks are full of nasty organisms, but thawing on the counter all day should be fine. A few hours sitting on the sideboard won't ruin the meat--remember that many meats are hung for a few days anyway. Besides, there just isn't enough time for toxins to accumulate, and cooking will kill off any micro-organisms.

As a last defense, one's immune system is pretty trustworthy:-)



NOTE to all...I don't remove the meat from the freezer bag. It remains in the bag until cooking time, and yes for the smartass .. COOK the meat once thawed.

On another side note to the fish question. I am a very avvid fiserman and use the same method mentioned earlier. I freeze my cleaned fish fillets in large bags of water. I have kept and ate catfish over a year old using this method and there is no degredation in taste, etc.

AND .. you are very correct sir...VOILA! Thanks for pointing that out. =)
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Joe
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PostPosted: Thu Dec 08, 2005 7:59 am    Post subject: Reply with quote

Re: thawing with the griddle: I guess out of habit I put it on the stove top -- i didn't turn on the burners, of course.

I ended up putting the fish in the fridge for an hour or so after it finished thawing, since it was faster than I thought it would be.
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PostPosted: Thu Dec 08, 2005 8:02 am    Post subject: Reply with quote

First: holy mackerel! What a great way of encoding a recipe!

Regarding bacteria: sometimes the biggest problem isn't the bacteria themselves but the toxins they produce. The entry for STAPHYLOCOCCUS AUREUS at the Virginia Department of Agriculture and Consumer Services says "Cooking won't destroy staph poison". Odd...I thought you just needed a high enough temperature. More grim details available at eMedicine.

While you're at the first URL, take at look at the other entries: symptoms can appear as long as 30 days after consumption. On a related note, consumption of moldy foods can be quite dangerous, causing permanent damage.

There should be an extension to the adage "what doesn't kill me makes me stronger":
What kills me, kills me. Or my guests: ("it was...the salmon
mousse!"). Oh, and sometimes what doesn't kill me just
cripples me for life.

I'll admit the modified form doesn't roll off the tongue quite as nicely, and doesn't lend itself to bravado. :-)

<preach>
You can spend your whole life with bad habits and never encounter a problem. However, I keep remembering a line from Tom Clancy's "Without Remorse", about Kelly/Clark "observing all the safety rules that had been written in the blood of less careful men". It's up to everyone to decide where to draw their personal line of caution; mine has tended to be a bit too far towards the incautious end of the spectrum and I've been burned a few times.
</preach>

On a lighter note, the main reason to get a chest-style "deep freezer" is because you can store food safely for longer periods. That's because it won't undergo the freeze-thaw cycles which frost-free, in-fridge freezers use (as often as every six hours) to avoid frost build-up. Technology geeks can see more detail at How Stuff Works and Appliance411.

-klode
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PostPosted: Thu Dec 08, 2005 8:02 am    Post subject: Reply with quote

Re leaving the chicken in the sink...
I do believe that the meat had been a) marinated and b) had spices added to it. Correct me if I am wrong but these additions do retard the growth of all of the nasty bugs everyone is freaking out about. Ever hear of cooked jerky? So properly seasoned before hand and marinated to boot before freezing sounds great to me. This is going to be a must try for me.
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Michael
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PostPosted: Thu Dec 08, 2005 8:02 am    Post subject: Reply with quote

Man you guys sound like a bunch of old women. A marinated and seasoned piece of chicken properly stored in a freezer bag sitting thawed for a couple of hours. Now correct me if I am wrong but jerky has never seen any type of cooking device, so the spices keep the growth of bacteria to a minimum. Or kill them altogether and before somebody asks, no I have never seen chicken jerky, but the principle should still apply nicely. As for thawing my aluminum sink is killer. Thanks Michael for the awesome website being a single guy its really easy to start getting bored with your own cooking and need to freshen things up. And I do love to cook!
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Mr. Ham Pie
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PostPosted: Thu Dec 08, 2005 8:03 am    Post subject: Reply with quote

Listen Gentlemen
Bacteria only exists on the outside of the meat.
So it can be washed off after you have finished defrosting.
For a good example of this, smell a piece of defrosted fish, then wash it, then smell again.
You will be amazed.
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Michael Chu



Joined: 10 May 2005
Posts: 1606
Location: Austin, TX (USA)

PostPosted: Thu Dec 08, 2005 8:03 am    Post subject: Reply with quote

re: bunch of old women
There are many similarities between the classic stereotype of an old woman and the minds of people predisposed to be engineers such as (1) we both believe what we believe, (2) we're both stubborn, and (3) we both have no problem saying what we believe. The difference is, even though an engineer might not immediately admit they are wrong, they will file away the discenting opinion in the backs of their mind as data and even possibly check it the next time they, let's say, encounter a turkey.

re: jerky
All the jerky I've known are dehydrated in an oven like contraption (an oven, a hot smoker, etc.). The dehydration serves as much to preserve the meat as the "spices". Most spices do little to extend the lifespan of a piece of meat, but salt and chile powders are effective (especially salt). In the case of the chicken on the counter for a couple hours to thaw, that's probably fine - but if it's a whole chicken or even large breasts, it's not just going to be two or three hours. The problem is that the exterior of the chicken thaws and rises above 40F while the inside is frozen. While waiting the couple hours for the inside to thaw, the bacteria is rapidly multiplying. Now you've got a bag potentially full of salmonella juices seasoned with secret herbs and spices that's sure to get a little bit on something else in the kitchen that's not being fully cooked. Not too big of a problem for most young people and others who have a strong constitution - maybe a mild bout of diarrhea and you're done. But for others, it can become a serious problem and even life threatening. (Very concerning if you cooking for others; guests should not go home and develop a tummy ache or worse.)

re: Washing meats
I don't know what mr. ham pie meant when he said washing meats - I imagine he's only rinsing. That helps clear away much of the by products of microbes, but rarely does rinsing remove a substantial amount of surface organisms. Soap and water and scrubbing can knock down the bacteria count by a few orders of magnitude, but that's not an option for meats. (I do recommend soapy water and scrubbing fruits & vegetables when you can because slicing into a fruit (with knives or teeth) with surface contamination will bring the bad stuff into the flesh.) Because it's difficult to clean the outside of meat, I recommend at least searing the outside to kill anything clinging on if you plan on severing anything raw (sashimi, carpaccio). If you don't like the sear, trim it off after you sear it. Does everyone have to follow all these precautions? Probably not, but if you're really risk adverse, then follow the safety tips we've outlined. Do I follow all of them? Usually, but there are times when I do a little risk taking (but not when I have guests).
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Adam
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PostPosted: Thu Dec 08, 2005 8:04 am    Post subject: Reply with quote

Now, the question I have for you all is this:

I have some t-bone steak with freezer burn (overnight - who would have thought?). Now, with freezer burn being as much about dehydration as, say for instance, jerky - would I be able to turn my steak into a jerky product that would be a) safe, and b) worth eating.....any ideas?
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