My cooking-knowledgeable friends tell me raw meat, once defrosted, must not be refrozen. Assuming it was kept cool and covered and only for a day or two, why would this be dangerous?
It’s not. The risk is exactly proportional to the time spent at temperatures where germs are comfortable growing.
The problem is that once refrozen it’s hard to keep track of how much time it was in that inbetween state when germs can grow.
If you are in the habit of refreezing meat, such as a cafeteria that has big bins of sausage that will reappear the next day, then the health department will cite you.
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I always thought that the re-freezing, especially in a home freezer, would cause the meat to loose it’s texture because the ice crystals would break it down. Maybe if it was completely thawed it would be ok.
Also the texture of the meat will not be as good if it is re-frozen. For something like hamburger it might not matter, but for a steak, it sure would. I’ve generally gone by the rule that if it is still partially frozen, you are o.k., but if it’s completely thawed, don’t refreeze it. If you’ve defrosted it at room temperature vs. in the fridge, definitely don’t refreeze. The bad stuff will have already started to grow a little during that time, and it will be a while before the second freezing stops them. Then the second time there are already more thingies ready to start breeding all over again. Better safe than sorry – if you’ve ever had, or known someone who had food poisoning of any kind, you would much rather waste the meat than go through that.
I don’t understand why it’s okay to bring meat home from the store and then freeze it. It’s not frozen at the store… what gives?
Also, what if you took the meat of the freezer and put it in the fridge to dethaw, could you re-freeze it then assuming it hasn’t been sitting on the counter for any amount of time?
Meat thawed at room temperature should not be refrozen, because bacteria have an opportunity to grow. Actually, meat should not be thawed at room temperature (or in standing water) for the same reason.
Meat thawed in the fridge can be safely returned to the freezer, although I can’t speak for any changes in quality caused be re-freezing.
My understanding is the bacteria arguement is generally accepted as being the reason it is recommended that meat isn’t refrozen. ie It defrosts, bacteria start to grow on it, you you re-freeze it and then thaw it and there are already more bacteria ready to grow. I guess if you brought your meat home from the store and froze it in a sterile, sealed bag thawed it and then refroze it you could get round this or, if you cooked the meat immediately after defrosting it the second time round and made sure it was well done.
Saying that, the meat that you get after a second freezing would be notably different in taste and texture than the original (as most fresh meat is to meat frozen only once). I’m a biologist and we go to extrordinary lengths to pre-treat tissue (essentially meat) before freezing it to make what are called cryosections (frozen tissue sections for microscope analysis). The problem is that all living cells are mostly water, you freeze them and the water forms ice and expands. This ruptures the cell membrane and releases cell components into the surroundings. A striking example of this can be seen with a strawberry. Place it in the freezer and it freezes and looks like a fresh strawberry. Let it defrost and it’ll turn to mush. The reason meat doen’t go instantly to mush is that the cell has a somewhat elastic membrane around it whereas strawberries have a rigid cell wall. Nonetheless, some meat cells will break open (particularly on the outside). Obviously the more times you freeze-thaw the more cells will rupture. Once the cells rupture a lot of enzymes are released that are involved in breaking down parts of the cell.
The above guideilines on thawing at room temp can be relaxed a bit if you cook your food properly; meaning not “rare”. It’s common practice for me to thaw stuff in warm water, then straight into the oven - never had a problem so far. I do this mostly because I lack the ability to predict what I’ll want to eat 12 hours from now, so when I decide I want something (frozen) if I don’t eat it that day I most likely will fancey something else by the time it would have thawed “safely”, hence I need to get it cooked fast.
Just two days ago my dad thawed what he thought was two packages of ground beef, only to find one was a pork roast (which we wouldn’t re-freeze). Ate the ground beef that night, put the roast in the fridge for ~ 18 hours and cooked/ate it yesterday. All’s well today.
How bad can food poising be if your cooking it properly? granted steaks might be a bit dangerous but if your doing something requiring mince or strips of meat, shouldnt the cooking kill and germs?
Cooking can kill the germs, but it doesn’t neutralize the toxins they’ve already produced.
Is this what causes freezer burn?