What You Can (And Can’t) Safely Do With Frozen Meat
Yesterday, we asked you:
❝You have meat in the freezer. How long is it really safe to keep it?❞
…and got a range of answers, mostly indicating to a) follow the instructions (a very safe general policy) and b) do not refreeze if thawed because that would be unsafe. Fewer respondents indicated that meat could be kept for much longer than guidelines say, or conversely, that it should only be kept for weeks or less.
So, what does the science say?
Meat can be kept indefinitely (for all intents and purposes) in a freezer; it just might get tougher: True or False?
False, assuming we are talking about a normal household electrical freezer that bottoms out at about -18℃ / 0℉.
Fun fact: cryobiologists cryopreserve tissue samples (so basically, meat) at -196℃ / -320℉, and down at those temperatures, the tissues will last a lot longer than you will (and, for all practical purposes: indefinitely). There are other complications with doing so (such as getting the sample through the glass transition point without cracking it during the vitrification process) but those are beyond the scope of this article.
If you remember back to your physics or perhaps chemistry classes at school, you’ll know that molecules move more quickly at higher temperatures, and more slowly at lower ones, only approaching true stillness as they near absolute zero (-273℃ / -459℉ / 0K ← we’re not saying it’s ok, although it is; rather, that is zero kelvin; no degree sign is used with kelvins)
That means that when food is frozen, the internal processes aren’t truly paused; it’s just slowed to a point of near imperceptibility.
So, all the way up at the relatively warm temperatures of a household freezer, a lot of processes are still going on.
What this means in practical terms: those guidelines saying “keep in the freezer for up to 4 months”, “keep in the freezer for up to 9 months”, “keep in the freezer for up to 12 months” etc are being honest with you.
More or less, anyway! They’ll usually underestimate a little to be on the safe side—but so should you.
Bad things start happening within weeks at most: True or False?
False, for all practical purposes. Again, assuming a normal and properly-working household freezer as described above.
(True, technically but misleadingly: the bad things never stopped; they just slowed down to a near imperceptible pace—again, as described above)
By “bad” here we should clarify we mean “dangerous”. One subscriber wrote:
❝Meat starts losing color and flavor after being in the freezer for too long. I keep meat in the freezer for about 2 months at the most❞
…and as a matter of taste, that’s fair enough!
It is unsafe to refreeze meat that has been thawed: True or False?
False! Assuming it has otherwise been kept chilled, just the same as for fresh meat.
Food poisoning comes from bacteria, and there is nothing about the meat previously having been frozen that will make it now have more bacteria.
That means, for example…
- if it was thawed (but chilled) for a period of time, treat it like you would any other meat that has been chilled for that period of time (so probably: use it or freeze it, unless it’s been more than a few days)
- if it was thawed (and at room temperature) for a period of time, treat it like you would any other meat that has been at room temperature for that period of time (so probably: throw it out, unless the period of time is very small indeed)
The USDA gives for 2 hours max at room temperature before considering it unsalvageable, by the way.
However! Whenever you freeze meat (or almost anything with cells, really), ice crystals will form in and between cells. How much ice crystallization occurs depends on several variables, with how much water there is present in the food is usually the biggest factor (remember that animal cells are—just like us—mostly water).
Those ice crystals will damage the cell walls, causing the food to lose structural integrity. When you thaw it out, the ice crystals will disappear but the damage will be left behind (this is what “freezer burn” is).
So if your food seems a little “squishy” after having been frozen and thawed, that’s why. It’s not rotten; it’s just been stabbed countless times on a microscopic level.
The more times you freeze and thaw and refreeze food, the more this will happen. Your food will degrade in structural integrity each time, but the safety of it won’t have changed meaningfully.
Want to know more?
Further reading:
You can thaw and refreeze meat: five food safety myths busted
Take care!
