If meats are kept at a low temperature to the point that bacteria can’t form to dangerous levels, how is it that there is still a shelf life for frozen meat?
In: Biology
I think it has more to do with how ice breaks down the cellular structures, and “breaks” the meat cells, in other words “freezer burn”.
It’s a physical/chemical process versus a bacterial “spoiling”. That make the meat that’s “burned” by ice formation, unpleasant but it’s not spoiled. You can after defrosting, cut away the burnt ends/edges.
Cold (above freezing) doesn’t completely prevent bacteria from forming, it just slows down their reproduction. Since bacterial growth is exponential, eventually enough bacteria will have multiplied in refrigerated meat to pose a health risk.
Frozen meat is a bit different. It’s quite difficult for any bacteria to actually reproduce in something that’s fully frozen solid. In theory, a vacuum sealed frozen meat product has an indefinite deep frozen shelf life. However freezer temperatures can sometimes fluctuate and give bacteria an opportunity to multiply. The main reason that frozen food spoils is mainly due to freezer burn (dehydration and oxidation) in improperly stored items. And this spoilage isn’t a health risk, it just makes the food taste awful and have an unpleasant texture. Plastic packaging also has its own expiry date, past which point it can’t be guaranteed to prevent moisture loss or oxidation, or possibly offgassing of chemicals/deterioration of the plastic.
I have eaten meat that I properly stored frozen for years and it was perfectly fine.
I’m so glad you asked this! Because you asked this, you are now smarter and less prone to food poisoning than most adults out there. First of all, your freezer/refrigerator is not a time machine. Neither is it a cryo chamber designed to preserve anything you put in it until 2140.
Now onto the answer. Just because something is frozen, that doesn’t mean bacteria can’t grow. Some bacteria can be extremely resilient and while most of the bacteria may have stopped growing in your freezer, some bacteria is still growing albeit at a very slow rate and since bacteria grows by doubling itself over time, that means the bacteria growth can sort of snowball into spoilage. Not only that but did you know that every time you store something in your freezer, you’re also storing a mew batch of bacteria into your freezer. If bacteria were like soldiers, you just sent them back up. That’s why its very important to clean your freezer and refrigerator every 6 months. Congrats! You’re now smarter than my father, who refuses to believe that food can still spoil in the freezer!
Meat stored wrapped and frozen (without thawing) will be wholesome indefinitely However, it’s flavor will worsen over time. Year-old meat is safe to eat, but you might not find it delicious.
also please consider there are two types of freezers.
chest freezer is very different to your normal freezer fridge in one regard, frost management.
fridge freezer defrosts because no one likes seeing ice buildup, now how does it defrost if it’s kept constantly way under freezing temperature?
it stops cooling and heats the panel most likely to have ice build up to melt away the ice!
that’s why stuff spoils in the freezer. also reason why not to get a chest freezer with auto defrost function, as it totally defies the purpose of a chest freezer.
My parents had a large chest freezer freezer that was very old and never emptied just topped up with new frozen purchases . It was well over 20 years old rusty but still working . They finally retired and moved out into a small retirement home. I got the job of cleaning it out . There was multiple pork joints in the bottom being saved for a special occasion that never came . I defrosted one and cooked it it was fine . So did the rest over the next few weeks . They were all in excess of 15 years old apparently !!
According to the USDA, meat stored ay 0 degrees or below is safe indefinitely, but loses quality over time.
https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/freezing-and-food-safety
If you want to stop all chemical reactions and bacteria growth, you need a lot lower temperature than your freezer.
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