Why should you not defrost things, then refreeze them?



Why should you not defrost things, then refreeze them?

In: Other

A couple reasons. One is bacterial build up. Another is texture. When you freeze something in a normal freezer, ice crystals build up and damage the cells. When you thaw it, those cells rupture. This leads to a bad texture and makes it more available for bacteria. Freezing again just causes more damage.

Water expands when it freezes. So when an object freezes the water expands and this breaks cellular walls. If you freeze thaw and refreeze food than more of the cellular walls of the food will have broken and the texture of the food will be damaged.

In addition it is a food safety concern when talking about meats as bacteria will have a chance to grow during the time the food is thawing and going back down to below freezing.

Freezing food doesn’t reset the timer on how long something can be thawed without spoiling, it just pauses it. While in specific cases where you carefully track how much time was spent thawed it might be okay, getting in that habit dramatically increases the chances that something has accumulated enough time thawed to spoil.

from my understanding, its not unsafe to refreeze IF thawed in the fridge. the cells of the food do break down after repeated freeze/thaw which compromises the quality of the food but does not make it any less safe to consume. However, if the food (especially raw protein) is thawed at room temp you should not refreeze. at room temp you give bacteria a much larger window to and therefore the food should be cooked at that time

The most important thing is food safety, so food is not froze and growing bacteria, frozen when the bacteria are in stasis, then defrosted when they’re growing again. If you freeze it again and thaw it again the bacteria will be allowed to grow for twice as long, and bacteria grow exponentially, so 2-4-8-16, etc. Texture suffers but that’s less important for certain things like ground meat that are likely to be spiced anyways.

bacteria activity produce toxins above
freezing. you can freeze / thaw at will, but toxins remain so it adds up and at a certain level it will make you sick

crystals and texture and “what not” do not make you sick

Have you ever put a full water bottle in the freezer? Usually it breaks somewhere. Imagine that bottle of water is just 1 cell in a piece of meat. Imagine all the cells in the meat doing that when Frozen. Once thawed you would have a lot of broken cells that have leaked out all their fluid leaving the cells deflated and the texture of the meat overall ruined.

How food is frozen matters! When water freezes it doesn’t just get bigger, it forms crystals like little ice knives that stab through the cell walls causing damage. Commercial flash freezing results in smaller crystals than freezing food at home. If you thaw your commercially frozen food and then freeze it again at home the cell damage will be much worse the second time.