Fridge burn?

[cjsmith]

Put a pound of ground beef in a self-defrost freezer and pretty soon it'll be brown around the edges.

Put it in the fridge and sooner or later you'll see a similar brown. I don't think my fridge crosses the freezing point, not since we lost an expensive bottle of insulin to that very thing and messed with the thermostat a tad. Is the blood simply draining out of the tissue? What's going on there?

Comments

[aelfie.livejournal.com]

I think its just oxygenation. Most meat packages aren't completely sealed, so air leaks in.

[cjsmith.livejournal.com]

Yeah, the packages have air in them when they're wrapped, too. It's definitely happening most where air touches it. What exactly is changed, then? What are the benefits of eating meat that has not had this happen, or the dangers of eating meat that has?

[klwalton.livejournal.com]

Meat turns brown when exposed to oxygen. The process in itself doesn't spoil the meat; it's perfectly safe to eat. A lot of processors package meat in sealed packages pumped with nitrogen because it keeps the meat red. I tend to think of red ground meat as fresher. Mainly because it is - there hasn't been time for oxygenation to kick in.

Correction: The gas pumped into the packaging is a combination of carbon dioxide (30%) and nitrogen(70%). I had to look it up :).

[cjsmith.livejournal.com]

Thanks! If that tint isn't spoilage, how can I best determine when it *is* spoiling? Scent?

[klwalton.livejournal.com]

Pretty much. I go by the rule that once I thaw ground beef, I use it within three days or it gets tossed. If I buy it and put it in the refrigerator, three days past sell-by date is my cut off. Ground meat is more likely to give you problems than whole pieces of meat - all that surface area :).

[commander-zero.livejournal.com]

What is called freezer burn is simplya very advanced dessication. The meat dried out in the dry cold environment. It isnt bad for you , but its not very tasty. Freezer burn is easily prevented by wrapping meat in plastic wrap before freezing, making sure to leave no airspace.

Best method is to use a vaccuum sealer. I routinely use meat a couple years old with no problems.

[just-cyd.livejournal.com]

thank you for asking the question that had stumped me, but not enough to see answers.

i am always perplexed whne my ground beef in the pkg is brown on top, but still pink underneath. now i know. stoopid oxygen. ;-)

[gdmusumeci.livejournal.com]

It's just oxidation -- bummer, huh? More disappointments courtesy of organic chemistry. :)

[aelfie.livejournal.com]

Unless the meat's gone bad (which you can tell by smell) its still safe to eat. Its just a looks thing. Most fresh meat you eat has been dead for a couple weeks by the time you get it (its that aging thing).

I'm not sure exactly what's changed, but since we've got an iron based blood system...makes sense that our red blood turns brown when exposed to oxygen. Or well, at least it does to me.

[rfrench.livejournal.com]

Rusty meat! Yum!

[aelfie.livejournal.com]

People who like their beef well done (i.e. don't like seeing pink) are now hating that nitrogen exposure. It causes "Persistent Redness", so even when the meat is fully cooked past the well done temperature, it still looks rare.

My DH and MIL HATE this. They eat their meat well done 'cause its still raw until the pink is gone. So they now have to truly destroy the meat before they will eat it. I throw more money down the sink because of that man.

[cjsmith.livejournal.com]

Well, freezer burn also involves bursting the cell walls, which I'm guessing isn't going on in my fridge. I had no idea oxygenation could turn muscle tissue brown -- after all, oxygenated blood is red -- but hey, learn something new every day. :-)

Yeah, now that I have a chest freezer, it might be worth looking into vacuum sealers. So far I haven't had anything long enough for freezer bern!

[cjsmith.livejournal.com]

Hah! Yeah, I figure in another year or two I wouldn't have had to ask that question. :-)

[cjsmith.livejournal.com]

So if we pour antioxidants all over it...? ;-) ;-)

[cjsmith.livejournal.com]

Three days, hrm? Okay. I can go by that rule.

I find thawing is a royal pain in the patootie. Do you thaw in the fridge, in the microwave, in some kind of water bath, ...?

[cjsmith.livejournal.com]

Oh interesting. I haven't had that problem. (Well, corned beef is a whole different question. I mean with regular "plain" cuts of meat.) I'm totally a well-done type, probably traumatized from living in France, but I have no problem getting things to go brown.

[cjsmith.livejournal.com]

My nose is pretty sensitive, so going by smell seems reasonable to me. I wonder, of course, at the borderline of things -- when it's started to have a few more bacteria and their byproduct toxins than you really want, but you can't smell them yet -- or maybe smell comes solidly before the stuff will make you sick. Come to think of it, evolution-wise, that last idea makes lots of sense.

[ed: I kan spel. yea.]

[klwalton.livejournal.com]

*If* I think about it ahead of time, I thaw in the refrigerator. Otherwise I just leave it out on the counter in the morning. Haven't died yet :).

On the other hand, if I'm using it in something like spaghetti sauce where I want to brown it and break it up, I'll throw it in the pan still frozen, and thaw and cook at the same time :).

I find a water bath can be a problem with ground meat, because the water *will* get in the meat and effectively soak all the juices out of it.

[cjsmith.livejournal.com]

It does smell different than when it's pink. But there's a whole 'nother smell that means BAD, and that's not it. I gotta ask stuff like this or some fine night you'll wake up hearing horrible sounds from the bathroom. :)

[cjsmith.livejournal.com]

That's how we always did it when I was a kid, too: on the counter in the morning. That worked until we got a dog tall enough to reach!

So if ground beef = 3 days, how about a chunk of roast or something? Same rule, or longer?

Thanks!

[klwalton.livejournal.com]

I rarely keep anything in the refrigerator longer than a day or two, just because I have a chest freezer. But I've been known to keep a roast or a steak in their for up to five or six days. If I buy a turkey within a week of cooking it, I keep it in the coldest part of the refrigerator rather than freeze then thaw. Chicken I'm more careful with, and fish gets cooked the day I buy it or, at most, the day after.

[commander-zero.livejournal.com]

Ah, but what color does the arterial spray on the ceiling turn after a few hours? Brown.

[cjsmith.livejournal.com]

Well, that's true. I guess I don't know how long stuff like clotting agents last after a chunk of muscle goes through a grinder. I clearly don't read the right kind of novels.

[cjsmith.livejournal.com]

I wind up keeping raw ingredients in the fridge whenever I get interrupted after the grocery run. I like to divide up the big economy packs of meat into reasonable sizes before freezing, chop the onion and the celery into ziplocs for future soup making, that sort of thing. If I can't do it when I arrive home, I may not have free time again for days. It's frustrating to lose stuff that way!

YAY NO FISH FOR ME EVER muahahaha! ;-)

[jcgbigler.livejournal.com]

The defrost cycle does bounce the temperature up and down to get rid of the frost build-up, so there could possibly also be some freezing & thawing going on around the edges.

The red in meat is from myoglobin, which stores oxygen in slow-twitch muscle cells. Like hemoglobin, myoglobin has an iron ion that binds the oxygen, and like hemoglobin, myoglobin is red when it's oxygenated.

One of the other common additives is carbon monoxide. CO bonds much more strongly to hemoglobin and myoglobin. When CO gets into our blood, it bonds so tightly that it effectively prevents oxygen from being able to get into the blood, and we asphyxiate. For the same reason, CO bonds more strongly to myoglobin and keeps the meat red even in the presence of oxygen. The CO levels are low enough to not be a health risk, but they can fool you into thinking the meat is a lot fresher than it is.

Of the various descriptions of what's happening as meat turns brown, the one that seems to make the most sense to me is that the red color is from Fe⁺² ions. Fe⁺³ is brown. It would seem that either cooking the meat or exposing it to oxygen will oxidize the Fe from +2 to +3.

[cjsmith.livejournal.com]

You are awesome.

Yeah, freezing/thawing = freezer burn, but I was pretty sure there wasn't freezing/thawing in the fridge. Fe⁺³, huh? Thanks!

[inflectionpoint.livejournal.com]

Be careful with ground meats. Unless you grind it yourself or see the butcher do it, you may be eating meat that's got a lot of bits and pieces of rather unattractive things in it. If it's coming from factory farmed meat that went through an industrial plant, there's a strong chance that there are bits of poop and other cow by products in it. Grinding will mix it all up together, and while most of us have enough of an immune system to not really care about these things, if you are elderly, or immune compromised, or just sorta sickly, it can be very bad for you.

Cook it thouroughly, and follow the usual food safety rules. I still eat meat, and I still eat ground meat, but I'm much more careful than I used to be, after learning more about Industrial Meat.

Friend of mine buys a half cow a year from a rancher, and grinds it herself. I wish I had enough meat eaters in my life and a big enough freezer to make that worth doing. I also wish I could buy a lamb and grind it myself. I'd be a Very Happy Girl, even if tired and covered in blood.