Usually because a) food left to warm can grow bacteria (this is not the same as food heated where bacteria might be killed and then refrozen) and b) it can affect texture.
If you thaw something in the fridge, in most cases you can refreeze without issue. If you’ve left it open on the counter, you’re asking for trouble – and in a lot of cases you want to avoid this with poultry like chicken or turkey.
It’s just a rule of thumb that’s easy for grandmas to teach. A better rule is that food can only sit for so long at “room” temperatures which, even more specifically, are from 40°F to 140°F. If you quickly thawed your frozen dumplings and then boiled them or even heated them to near boiling in your soup you can freeze a portion of the soup for later and be perfectly within even the most paranoid of safety guidelines.
It’s not a safety issue, it’s a quality issue. Every time you freeze and defrost something, ice crystals are forming and informing and making the food mushy.
Bacteria like to grow around temperatures humans like, when the manufacturers freeze them they have to follow strict regulations that bring down the temperature past that Bacteria growing zone to freezing without letting Bacteria grow. They use they use special flash freezers that can achieve this speed, you, cannot. At the same time it’s just acceptable risk, producers make thousands of meals and can’t let 1% make people sick, you can probably deal with a 1% risk
From a food safety perspective, it makes it harder to track how much time the food has spent at a warm enough temperature to grow bacteria, and how long that bacteria has had to produce toxins. Freezing pauses the clock, but it doesn’t kill the bacteria. Cooking can kill the bacteria but won’t get rid of the toxins.
If you cook something straight from frozen, there’s much less issue than for something that gets thawed out before cooking.
Freezing doesn’t kill bacteria, merely puts it to sleep.
Once the bacteria gets above a certain temperature, it starts to wake up and reproduce – the warmer, the faster – and eventually getting to a point where they can overwhelm our bodies defenses, making us sick.
If you then re-freeze the food you’re now putting a greater population of bacteria to rest.
If said food is then improperly cooked/reheated the results could be dire.
As stated in other responses as well, there are quality issues.
From a food safety standpoint the problem is food can only be left in the danger zone temperature for a certain period of time before it will make you sick. Freezing does not roll back that clock it just pauses the clock.
Let’s imagine you can get to a count of ten on the danger zone clock before it will make you sick. You buy a piece of food. It has 1 on the clock from handling in the store. You put it in the freezer and stop the clock. Weeks later you take it out and thaw it on your counter. You add 5 to your clock for thawing time so your food is at 6 (1 from the store + 5 from thawing). 6 is still safe so you won’t get sick. You put part of it back in the freezer and stop the clock. A few weeks later you take the rest out and thaw it in your counter again adding another 5 to the clock. You are now at 11 (1 from store + 5 from first thaw + 5 from second thaw). 11 is over the safety line of 10 so you might get sick. If you put some of it back in the freezer and do this again, you will be at 16 and get very sick.
It is possible to refreeze things safely if you handled it safely between rounds. But each time you do increases the chances of getting sick. Many people do a horrible job of following food safety so a good rule of thumb is not to refreeze something.
In your case you are likely safe. Cooking food will roll back the food safety clock some. There are two things that can make you sick, the bacteria itself, and the bacteria’s waste products. Cooking will kill most of the bacteria. For some bacteria it will also destroy some of its waste product. But it won’t kill all the bacteria and it won’t destroy all of the waste product. So cooking might roll your safety clock of 6 after the first thaw back to a 3. You can put the leftovers in the freezer and safely use it again in the future because your thaw will still be below the safety line.
The rule of thumb on refreezing really applies to things in the state they were last frozen. Cooking changes the state so you can safely freeze leftovers made out of something that had originally been frozen.
The real issue is food quality, but let me address the safety issue first. People are misunderstanding it imo.
Food is all on the same “contagion clock” while unfrozen. Freezing slows down the clock to nearly zero – but does not reset it.
Let’s say you get two chicken breasts at the store. You keep both in the fridge for a day. Then you freeze one and leave the other in the fridge.
After a day, you thaw the frozen breast, then freeze it again. It is still behind the never-frozen breast, in terms of the contagion clock.
Where this gets tricky is if people think the clock was reset after freezing. People should only keep chicken raw on the fridge for about two days. So let’s say somebody kept the breast in the fridge for two days, then froze it, and then thawed it. The clock did not reset: it has the same two-days-old contagion risk.
The real reason is quality. Water expands when it turns to ice. This tears at the food, like when the Hulk comes out and tears his clothes. The first time you freeze and thaw, you can get away with it, the damage is limited. But the more you do it, the more times the ice has torn things, and the mushier your food gets. Meat in particular gets gross. Using the Hulk metaphor, his pants may survive the first Hulking, but maybe not the second.
You can, it just makes the quality of the food go down and the freeze and that and freeze and that breaks down the structure of the food. So your broccoli or whatever is gonna be mushy.
It’s also a food safety concern because people may forget that freezing just pauses rotting, not reset it. So if you let food thaw, and bacteria starts to grow on it, and then freeze it again. When you thaw it in the future some of that bacteria will still be there
Actually, it is more about your food texture and quality rather than safety.
When food is frozen normally, like in your freezer, the ice formation results in bigger crystals. This can destroy the cell wall or the molecule structure. As a result, the quality gets degraded and the food cannot retain its structure.
Most packaged frozen food is flash frozen, or frozen very quickly. This ensures smaller ice crystal formation and it is more even, thus less damage to the cell wall or the structure.
Food safety is decided by your method of thawing. If you leave your frozen stuff outside and at room temperature, bacteria either in your stuff or in the environment can start multiplying on your food. This makes your stuff dangerous regardless of whether you put the food back into the freezer or not since the freezing process only deactivates the bacteria and does not kill them outright, nor remove the toxins created by the bacteria.
Thawing your food in the fridge will reduce bacteria activity so it is safer that way.
Comments
Usually because a) food left to warm can grow bacteria (this is not the same as food heated where bacteria might be killed and then refrozen) and b) it can affect texture.
If you thaw something in the fridge, in most cases you can refreeze without issue. If you’ve left it open on the counter, you’re asking for trouble – and in a lot of cases you want to avoid this with poultry like chicken or turkey.
It’s just a rule of thumb that’s easy for grandmas to teach. A better rule is that food can only sit for so long at “room” temperatures which, even more specifically, are from 40°F to 140°F. If you quickly thawed your frozen dumplings and then boiled them or even heated them to near boiling in your soup you can freeze a portion of the soup for later and be perfectly within even the most paranoid of safety guidelines.
If you remove the food safety issues…
When you freeze something, ice crystals can break the cells walls; when you thaw more liquid will leach out.
The reason we try to freeze as quickly as possible to have the smaller ice crystals and thaw as slowly as possible.
It’s not a safety issue, it’s a quality issue. Every time you freeze and defrost something, ice crystals are forming and informing and making the food mushy.
Bacteria like to grow around temperatures humans like, when the manufacturers freeze them they have to follow strict regulations that bring down the temperature past that Bacteria growing zone to freezing without letting Bacteria grow. They use they use special flash freezers that can achieve this speed, you, cannot. At the same time it’s just acceptable risk, producers make thousands of meals and can’t let 1% make people sick, you can probably deal with a 1% risk
From a food safety perspective, it makes it harder to track how much time the food has spent at a warm enough temperature to grow bacteria, and how long that bacteria has had to produce toxins. Freezing pauses the clock, but it doesn’t kill the bacteria. Cooking can kill the bacteria but won’t get rid of the toxins.
If you cook something straight from frozen, there’s much less issue than for something that gets thawed out before cooking.
Freezing doesn’t kill bacteria, merely puts it to sleep.
Once the bacteria gets above a certain temperature, it starts to wake up and reproduce – the warmer, the faster – and eventually getting to a point where they can overwhelm our bodies defenses, making us sick.
If you then re-freeze the food you’re now putting a greater population of bacteria to rest.
If said food is then improperly cooked/reheated the results could be dire.
As stated in other responses as well, there are quality issues.
From a food safety standpoint the problem is food can only be left in the danger zone temperature for a certain period of time before it will make you sick. Freezing does not roll back that clock it just pauses the clock.
Let’s imagine you can get to a count of ten on the danger zone clock before it will make you sick. You buy a piece of food. It has 1 on the clock from handling in the store. You put it in the freezer and stop the clock. Weeks later you take it out and thaw it on your counter. You add 5 to your clock for thawing time so your food is at 6 (1 from the store + 5 from thawing). 6 is still safe so you won’t get sick. You put part of it back in the freezer and stop the clock. A few weeks later you take the rest out and thaw it in your counter again adding another 5 to the clock. You are now at 11 (1 from store + 5 from first thaw + 5 from second thaw). 11 is over the safety line of 10 so you might get sick. If you put some of it back in the freezer and do this again, you will be at 16 and get very sick.
It is possible to refreeze things safely if you handled it safely between rounds. But each time you do increases the chances of getting sick. Many people do a horrible job of following food safety so a good rule of thumb is not to refreeze something.
In your case you are likely safe. Cooking food will roll back the food safety clock some. There are two things that can make you sick, the bacteria itself, and the bacteria’s waste products. Cooking will kill most of the bacteria. For some bacteria it will also destroy some of its waste product. But it won’t kill all the bacteria and it won’t destroy all of the waste product. So cooking might roll your safety clock of 6 after the first thaw back to a 3. You can put the leftovers in the freezer and safely use it again in the future because your thaw will still be below the safety line.
The rule of thumb on refreezing really applies to things in the state they were last frozen. Cooking changes the state so you can safely freeze leftovers made out of something that had originally been frozen.
The real issue is food quality, but let me address the safety issue first. People are misunderstanding it imo.
Food is all on the same “contagion clock” while unfrozen. Freezing slows down the clock to nearly zero – but does not reset it.
Let’s say you get two chicken breasts at the store. You keep both in the fridge for a day. Then you freeze one and leave the other in the fridge.
After a day, you thaw the frozen breast, then freeze it again. It is still behind the never-frozen breast, in terms of the contagion clock.
Where this gets tricky is if people think the clock was reset after freezing. People should only keep chicken raw on the fridge for about two days. So let’s say somebody kept the breast in the fridge for two days, then froze it, and then thawed it. The clock did not reset: it has the same two-days-old contagion risk.
The real reason is quality. Water expands when it turns to ice. This tears at the food, like when the Hulk comes out and tears his clothes. The first time you freeze and thaw, you can get away with it, the damage is limited. But the more you do it, the more times the ice has torn things, and the mushier your food gets. Meat in particular gets gross. Using the Hulk metaphor, his pants may survive the first Hulking, but maybe not the second.
You can, it just makes the quality of the food go down and the freeze and that and freeze and that breaks down the structure of the food. So your broccoli or whatever is gonna be mushy.
It’s also a food safety concern because people may forget that freezing just pauses rotting, not reset it. So if you let food thaw, and bacteria starts to grow on it, and then freeze it again. When you thaw it in the future some of that bacteria will still be there
Actually, it is more about your food texture and quality rather than safety.
When food is frozen normally, like in your freezer, the ice formation results in bigger crystals. This can destroy the cell wall or the molecule structure. As a result, the quality gets degraded and the food cannot retain its structure.
Most packaged frozen food is flash frozen, or frozen very quickly. This ensures smaller ice crystal formation and it is more even, thus less damage to the cell wall or the structure.
Food safety is decided by your method of thawing. If you leave your frozen stuff outside and at room temperature, bacteria either in your stuff or in the environment can start multiplying on your food. This makes your stuff dangerous regardless of whether you put the food back into the freezer or not since the freezing process only deactivates the bacteria and does not kill them outright, nor remove the toxins created by the bacteria.
Thawing your food in the fridge will reduce bacteria activity so it is safer that way.