Why won’t microwaving spoiled food make it safe to eat?

1.06K views

My understanding is that the cells of bacteria and fungi are filled with water enclosed in a balloon. Wouldn’t microwaving then pop the balloons?

In: Biology

12 Answers

Anonymous 0 Comments

Everyone here is forgetting something. The wavelength of microwaves do not heat up bacteria.

Take a look at [this video](https://youtu.be/B8nnPYBc4hc). Ants can roam about in the *inside* of microwaves without being harmed, because they are smaller than the microwave wavelength. Much less bacteria.

So you can’t technically kill bacteria by putting them in the microwave. The heat from the actual food being heated *might* kill the bacteria, but it’s not “directly” from the microwave.

And then there’s the toxin part which everyone is referring to.

Anonymous 0 Comments

A common form of food poisoning is caused by the bacteria Staphylococcus aureus. It releases staph toxin that after a few hours causes involuntary vomiting. Killing the bacteria with heat will not break down the staph toxin.

Anonymous 0 Comments

Food scientist here. You are partially correct. But microwaving doesn’t make a food safe for two reasons. There are two different types of foodborne illness, infections and poisoning.

Listeria and salmonella are two examoles of infections. They are able to get through your stomach and into your intestines, and from there to other areas of the body where the cells themselves grow and divide.

Botulism is a type of food poisoning caused by the toxin produced by clostridium botulinum. This is literally the same toxin used in Botox.

The first reason microwaving won’t make a bad food safe that, while most of the infectious cells will burst and die, there are some that will make it through. Even in industrial processes, there isn’t ever a guarantee that all the cells get burst. The odds are very slim, but there is always a chance a mutated or super resistant cell will survive to cause problems

The second reason is that the toxins bacteria produce are extremely heat stable. Industrial canning processes, which hold food at 250°F for 30+ minutes, isn’t able to destroy the toxins. There is no way a home microwave could ever achieve that kind of temperature throughout a food product.

Anonymous 0 Comments

There are two common toxic pathways for food born bacteria. One is called an exotoxin. These are excreted by live bacteria into their surroundings, and can make you sick. The other type are called endotoxin’s. These are structural elements usually part of the bacterial cell wall. They can make you sick as well. These endotoxin’s can remain toxic even when the bacteria has died or broken apart. You may be able to remove the threat of exotoxin by killing the bacteria via heat, but endotoxin’s (left there from the dead or destroyed bacteria) can still cause sickness.

Anonymous 0 Comments

The bacteria don’t hurt you. Their poop does. They pooped all in your food, and you just microwaved it, got it nice and hot, and let all the flavors get to know each other.

Anonymous 0 Comments

Basically, the bacteria and fungus may die. But they leave behind toxins and other nasty things designed to get rid of competition. The microwave can’t kill all of those so you get sick from that.

Anonymous 0 Comments

When food spoils it is because bacteria/fungi have established themselves and colonies have grown to the size that their effects on the food become noticeable. If you then eat this food it can make you sick.

Sure, you can cook the food and this will kill the bacteria/fungi, but you can still become sick if you eat this food because they weren’t necessarily what was going to make you sick.

All the time they were present on the food, they were “eating” the food, secreting chemicals and waste into the food. These chemicals (Toxins) are what will make you ill, they’re what gives spoilt food that horrible smell and taste, and they don’t disappear with a little heating as these simple chemicals (relatively speaking) are far more stable than a complex microorganism.

Super ELI5: Microbes have been vomiting and pooping all over your steak, just because you’ve cooked it doesn’t mean your steak isn’t still full of poop.

Anonymous 0 Comments

microwaving heats food up killing the germs but germ’s poop stays there and can still make you sick.

Anonymous 0 Comments

You’re quite right about bacteria and fungi effectively being water wrapped up in a balloon (a cell membrane)! The application of heat (by microwaving or other heat like ovens) basically shakes apart the cell membrane, resulting in the cell ripping apart- think like how an earthquake shatters a buildings walls down.

This isn’t the be all and end all. The bacteria and fungi were able to exist and divide massively in your food because, well, it’s a food source! As time went by on the foods expiry date, the fungi/bacteria were able to rapidly divide and exponentially multiply. While they were doing this they were making various proteins to break down the food that they pumped outside of themselves and soaked all around the food.

These proteins are more temperature stable than living cells, and last on even after intense heating like cooking. These proteins are often toxins and are hazardous to you, me and many other animals that leave food alone for a bit too long. Evolution for us has prepared us for this by being able to detect rancid food and be scared off by it- hence why you often know something is off just by smelling it!

Hope this helps answer your question

Anonymous 0 Comments

When food spoils it usually means that mold and bacteria have started to grow on it. While you can kill these if you apply enough heat for enough time, this won’t destroy the toxins they have produced, and those can still make you ill. In addition, microwaves work over a short time and heat up food unevenly, so there can easily be patches where bacteria survived.