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View Full Version : Can microwave sterilize food?


Calculator83
05-29-2008, 01:16 PM
I'm trying to cook more from the microwave, And i just want to know.

f95toli
05-29-2008, 01:20 PM
Not as such.
But heat kills most germs meaning a microwave owen is just a safe as a conventional owen. As long as you make sure meat, poultry etc is properly cooked before you eat it you will be ok.

Cogman
05-29-2008, 09:29 PM
What he said, as long as you get it to the right recommended temperature, you should be fine, just make sure you treat some things especially careful (Poultry, Pork, and Fish can be really bad for food poisoning, not so much beef)

Gibsons
05-30-2008, 12:06 PM
There's a difference between sterilizing and cooking.

A microwave oven can make food just as safe as boiling or steaming, but you'll need a little more than that to be 100% certain of sterilization in most cases. But there's no need to do that for most any food.

If you want to sterilize stuff in a home environment, a pressure cooker is probably your best bet.

CycloWizard
05-30-2008, 12:34 PM
Originally posted by: Cogman
What he said, as long as you get it to the right recommended temperature, you should be fine, just make sure you treat some things especially careful (Poultry, Pork, and Fish can be really bad for food poisoning, not so much beef)
Pork is actually very safe now, at least in the US. Trichinosis has been gone for almost 35 years (again, in the US). I now enjoy my pork chops medium rare. :P

Cogman
05-30-2008, 06:16 PM
Originally posted by: CycloWizard
Originally posted by: Cogman
What he said, as long as you get it to the right recommended temperature, you should be fine, just make sure you treat some things especially careful (Poultry, Pork, and Fish can be really bad for food poisoning, not so much beef)
Pork is actually very safe now, at least in the US. Trichinosis has been gone for almost 35 years (again, in the US). I now enjoy my pork chops medium rare. :P

:) I guess I still cling to old wives tales, Im not even 35 years old and yet I have always heard that uncooked pork will most likely give you Trichinosis.

CycloWizard
05-30-2008, 06:18 PM
Originally posted by: Cogman
:) I guess I still cling to old wives tales, Im not even 35 years old and yet I have always heard that uncooked pork will most likely give you Trichinosis.
I always thought that too. That is, until I got engaged to the daughter of the world's foremost porcine veterinarian. :P Restaurants still don't want to serve him rare pork chops, but they usually concede.

KurskKnyaz
05-31-2008, 12:34 AM
The only thing that can sterilize anything is an autoclave. You can get your food hot enough to kill parasites. As for sterilization, you are out of luck. All the food you eat has bacteria or will be inoculated with it as soon as you take it out of the microwave, but that is okay. The guy who said a pressure cooker is your best bet is correct.

sjwaste
05-31-2008, 12:24 PM
Originally posted by: CycloWizard
Originally posted by: Cogman
:) I guess I still cling to old wives tales, Im not even 35 years old and yet I have always heard that uncooked pork will most likely give you Trichinosis.
I always thought that too. That is, until I got engaged to the daughter of the world's foremost porcine veterinarian. :P Restaurants still don't want to serve him rare pork chops, but they usually concede.

Heh, I have the same problem eating out. Most places won't cook my pork medium rare, at least not without insisting on it. They always ask or "recommend" a higher temperature. Since I don't want to debate the issue in a restaurant, usually just smiling and saying im willing to take the gamble gets the request granted.

BladeVenom
06-03-2008, 04:25 AM
Originally posted by: Cogman
Originally posted by: CycloWizard
Originally posted by: Cogman
What he said, as long as you get it to the right recommended temperature, you should be fine, just make sure you treat some things especially careful (Poultry, Pork, and Fish can be really bad for food poisoning, not so much beef)
Pork is actually very safe now, at least in the US. Trichinosis has been gone for almost 35 years (again, in the US). I now enjoy my pork chops medium rare. :P

:) I guess I still cling to old wives tales, Im not even 35 years old and yet I have always heard that uncooked pork will most likely give you Trichinosis.


I wouldn't call it an old wives tale. It use to be true. It's still true in less developed countries. Now about the only people to get Trichinosis in this country get it from wild game.

lousydood
06-04-2008, 11:23 AM
On a similar note, one time I saw someone "sterilizing" a cup by putting it (empty) in the microwave. I told her that wouldn't do anything because microwaves heat only water molecules specifically. But then I thought about it some more: wouldn't micro-organisms contain water and therefore be killed by the microwave anyhow? In any case, I don't consider it a good way to clean things, but perhaps it has more effect than I thought?

HVAC
06-04-2008, 03:53 PM
Nuclear radiation will sterilize things, though. Many things, including milk, are sterilized this way in europe. Once this is done, the containers may be put on the shelf (no refrigeration) and keep for several years without additional preservatives.

It is of course necessary to assure that there are low enough levels of metals that can activate (become radioactive) in the food treated this way.

BladeVenom
06-04-2008, 04:01 PM
Many spices are also irradiated for sterilization.

KurskKnyaz
06-04-2008, 05:13 PM
Originally posted by: lousydood
On a similar note, one time I saw someone "sterilizing" a cup by putting it (empty) in the microwave. I told her that wouldn't do anything because microwaves heat only water molecules specifically. But then I thought about it some more: wouldn't micro-organisms contain water and therefore be killed by the microwave anyhow? In any case, I don't consider it a good way to clean things, but perhaps it has more effect than I thought?


AFAIK the electromagnetic frequency of microwaves are close to the frequency of molecular motion. When you microwave something the microwaves undergo constructive interference with the wave properties of the moving molecules and so they absorb microwave energy, there molecular motion increases, they pass that on to surrounding molecules, and the end result is heat.

You can use it to "clean" something. But to sterilize, meaning remove all microbial agents, you cannot use a microwave. There are bacterial endospores that can survive ionizing radiation and temperatures as high as 140 C. Thats why surgeons use autoclaves.

Why are you all so worried about bacteria? Your body contains ~100 bacterial cells for every human cell. You also have an immune system and your kids will be fine if you don't use Lysol disinfecting spray. Our ancestors would fry something on a stick, eat it off a rock, and they were fine. The overwhelming vast majority of bacteria is harmless to humans.

QuantumPion
06-06-2008, 12:52 PM
Originally posted by: HVAC
It is of course necessary to assure that there are low enough levels of metals that can activate (become radioactive) in the food treated this way.

I don't know where you got this from but it's completely wrong. Food irradiation uses Cobolt-60, a gamma emitter. Photons of this energy do not induce radioactivity.

lousydood
06-06-2008, 02:56 PM
HVAC, what does radioactivity have to do with microwaves? Microwaves are the upper (shorter) end of the radio wave portion of the electromagnetic spectrum, close to infrared.

Back to topic: Kursk, I put "sterilize" in scare quotes on purpose. And recall, I wasn't trying to do this myself. It is true that there are many microbes in the human body and surrounding us. That doesn't make cleanliness a pointless habit. Might I remind you of the untold suffering that was common prior to the existence of modern plumbing and sewage systems? In the 19th century, even, how often people died from dysentery, cholera, and other easily preventable diseases? Or that surgery killed more than it saved? I think people forget -- or, take for granted -- how important hygiene, clean water, and sewage really is.

KurskKnyaz
06-07-2008, 05:26 AM
Back to topic: Kursk, I put "sterilize" in scare quotes on purpose. And recall, I wasn't trying to do this myself. It is true that there are many microbes in the human body and surrounding us. That doesn't make cleanliness a pointless habit. Might I remind you of the untold suffering that was common prior to the existence of modern plumbing and sewage systems? In the 19th century, even, how often people died from dysentery, cholera, and other easily preventable diseases? Or that surgery killed more than it saved? I think people forget -- or, take for granted -- how important hygiene, clean water, and sewage really is.



You are absolutely right about what you said. The point I was trying to make is that there is no point in sterilizing a cup, our society has this notion that bacteria will kill you. It is true that some will but most won't unless you are under unusual circumstances (surgery, malnutrition, etc). Cleanliness is not a pointless habit in specific situations. I would not use the same cutting board for meat and vegetables. However, sterilizing your toilet bowl and using Lysol on everything around the house is ridiculous. I have a class on a kitchen shelf that may have accumulated small amounts of bacteria. All your food has bacteria on it. The reason you keep it in a fridge is so that it does not grow to pathogenic amounts. I will have no problem drinking out of it because I know they are not pathogenic. I would not do that at a hospital though.

Cogman
06-07-2008, 08:58 AM
Originally posted by: HVAC
Nuclear radiation will sterilize things, though. Many things, including milk, are sterilized this way in europe. Once this is done, the containers may be put on the shelf (no refrigeration) and keep for several years without additional preservatives.

It is of course necessary to assure that there are low enough levels of metals that can activate (become radioactive) in the food treated this way.

Nuclear radiation is NOT used very commonly to treat food that way. Mostly they place the liquid under pressure and exposed it to ultra high heat for a few seconds. I lived in europe and never saw anything that claimed to be irradiated. Things with extra long shelf lives (like milk) would almost always say that they where treated under the ultra high heating process.

montag451
06-08-2008, 11:22 AM
One other thing to keep in mind is that it is the toxins that are produced by some bacteria that are poisonous.

So, even if you do sterilize to an extreme degree, there is still the chance that if the food was exposed to bacteria, bacterial toxins (forgotten the proper term - will probably remember when I sober up a little) still remain.

lightstar
06-08-2008, 05:07 PM
lots of tabasco sauce will kill anything

Paperdoc
06-09-2008, 10:18 AM
I'm guessing OP does not actually want to sterilize food, only cook it enough to be safe to eat and store for moderate time periods, same as other cooking techniques. IF that is his /her real question, microwaves can cook the same as other ways.

However, if you really do want sterilization, the answer is NO - microwaves are no better or worse than techniques like boiling, frying or roasting. While these will kill most bacteria (and even destoy some toxins previously deposited by bacteria), they will not kill ALL bacteria. One post recommended a pressure cooker for that, and it works because it cooks at temperatures significantly above 100 C (212 F) - you can't exceed that temperature at normal atmospheric pressure. BUT even then you need to use particular techniques, because the issue becomes how to seal the sterilized food in a container without re-contaminating it by handling after the cooking / cooling phases.

Although microwaves work by increasing the rotational energy (we sense as heat) of many molecules in the food, they cannot be relied upon to destoy critical molecules in bacteria, causing their death. The most reliable guide is still temperature - how hot the food gets. If the temperature does not guarantee that the food is safe enough, don't rely on microwaves to give you an extra margin of safety.

bobsmith1492
06-09-2008, 10:53 AM
Originally posted by: PaperdocOne post recommended a pressure cooker for that, and it works because it cooks at temperatures significantly above 100 C (212 F) - you can't exceed that temperature at normal atmospheric pressure. BUT even then you need to use particular techniques, because the issue becomes how to seal the sterilized food in a container without re-contaminating it by handling after the cooking / cooling phases.

Pressure canner? I think you can do things like pork without health issues.

QuantumPion
06-09-2008, 01:36 PM
Originally posted by: Cogman
Originally posted by: HVAC
Nuclear radiation will sterilize things, though. Many things, including milk, are sterilized this way in europe. Once this is done, the containers may be put on the shelf (no refrigeration) and keep for several years without additional preservatives.

It is of course necessary to assure that there are low enough levels of metals that can activate (become radioactive) in the food treated this way.

Nuclear radiation is NOT used very commonly to treat food that way. Mostly they place the liquid under pressure and exposed it to ultra high heat for a few seconds. I lived in europe and never saw anything that claimed to be irradiated. Things with extra long shelf lives (like milk) would almost always say that they where treated under the ultra high heating process.

It is used more commonly in Europe then it is in the Americas, primarily for spices, seasonings, etc. In the US it is used for tropical fruits. I haven't seen any irradiated food for sale although I'd love to buy irradiated pineapple from Hawaii.

Milk and other dairy products aren't irradiated for some reason, I can't recall exactly but I think it changes the flavor and makes it sour or something.

Radiation can be used to completely sterilize food or make otherwise perishable food shelf-stable, but this isn't commonly done (it's used for special applications, like astronaut food or food for AIDS patients).

PlasmaBomb
06-09-2008, 01:49 PM
Originally posted by: lousydood
HVAC, what does radioactivity have to do with microwaves? Microwaves are the upper (shorter) end of the radio wave portion of the electromagnetic spectrum, close to infrared.


Erm... microwaves come from the lower energy end of the spectrum and have wavelengths longer than visible light (beyond IR).

Paperdoc
06-09-2008, 10:24 PM
Originally posted by: PlasmaBomb
Originally posted by: lousydood
HVAC, what does radioactivity have to do with microwaves? Microwaves are the upper (shorter) end of the radio wave portion of the electromagnetic spectrum, close to infrared.


Erm... microwaves come from the lower energy end of the spectrum and have wavelengths longer than visible light (beyond IR).

lousydood is right, microwaves are the upper end of the radio wave portion of the em spectrum and yes, what comes next is Far-Infrared, then Infrared, then Near Infrared, then visible. I did research many years ago in the RF, microwave and Far-Infrared region. Our microwave equipment topped out at 150 GHz, or a wavelength of 2 mm, also called "5 wavenumbers" by IR spectroscopists. The Far-IR equipment covered about 5 to 150 wavenumbers. The common IR spectra cover 500 to 5000 wavenumbers.

Comdrpopnfresh
06-12-2008, 12:12 AM
I heard putting a sponge or dishcloth in the microwave for 10-15 seconds will kill off a lot of the microbes. Could just be the localized water being boiled and killing, or the radiation. I'd guess the water.

bobsmith1492
06-12-2008, 09:44 AM
Originally posted by: Comdrpopnfresh
I heard putting a sponge or dishcloth in the microwave for 10-15 seconds will kill off a lot of the microbes. Could just be the localized water being boiled and killing, or the radiation. I'd guess the water.

That has nothing to do with microbes; the point is that the water will evaporate and steam-clean the microwave - all the dried, stuck-on food can then be easily wiped off.

PolymerTim
06-12-2008, 03:20 PM
Actually, there was a study that showed that 2 minutes on full power was enough to kill 99% of germs. So it has been recommended as a method to disinfect sponges (probably a less rigorous term than sterilization). I remembered reading about this a while ago and was able to find it again.

http://www.msnbc.msn.com/id/16796327/

I think I remembered it because it was so funny since a lot of people didn't realize the sponge has to be wet. For those who think a microwave won't heat anything but water, think again. Actually, the microwave radiation can excite many things. I've even warmed dry ceramic plates in it before. It is just more efficient with some things than others. Like have you ever noticed that it is really bad at heating ice? Once the ice melts, though, it heats up very fast.

Here's a couple of my favorite excerpts:

When I tried it, my sponge caught on fire. It had been in the microwave for less than two minutes on full power. There were flames and when I poured water on the sponge it was totally charred.

The university issued the following advisory: ?To guard against the risk of fire, people who wish to sterilize their sponges at home must ensure the sponge is completely wet. Two minutes of microwaving is sufficient for most sterilization. Sponges should also have no metallic content. Last, people should be careful when removing the sponge from the microwave as it will be hot.

Yeah, make sure to tell people that after 2 minutes on full power in the microwave, the wet sponge will be hot. I love warning labels! :P

-Tim

Rudy Toody
06-12-2008, 11:13 PM
Originally posted by: PolymerTim
Actually, there was a study that showed that 2 minutes on full power was enough to kill 99% of germs. So it has been recommended as a method to disinfect sponges (probably a less rigorous term than sterilization). I remembered reading about this a while ago and was able to find it again.

http://www.msnbc.msn.com/id/16796327/

I think I remembered it because it was so funny since a lot of people didn't realize the sponge has to be wet. For those who think a microwave won't heat anything but water, think again. Actually, the microwave radiation can excite many things. I've even warmed dry ceramic plates in it before. It is just more efficient with some things than others. Like have you ever noticed that it is really bad at heating ice? Once the ice melts, though, it heats up very fast.

Here's a couple of my favorite excerpts:

When I tried it, my sponge caught on fire. It had been in the microwave for less than two minutes on full power. There were flames and when I poured water on the sponge it was totally charred.

The university issued the following advisory: ?To guard against the risk of fire, people who wish to sterilize their sponges at home must ensure the sponge is completely wet. Two minutes of microwaving is sufficient for most sterilization. Sponges should also have no metallic content. Last, people should be careful when removing the sponge from the microwave as it will be hot.

Yeah, make sure to tell people that after 2 minutes on full power in the microwave, the wet sponge will be hot. I love warning labels! :P

-Tim

Don't try this with a wet dog! Or a dry dog, either!