Microwaves: A Haven for Bacterial Diversity

https://tecscience.tec.mx/en/biotechnology/bacteria-in-microwave/

by rbanffy • 2 years ago

71 58 2 years ago

tecscience.tec.mx

galdosdi2• 2 years ago

Because microwaves don't heat matter. They heat* H2O molecules. This one weird fact is responsible for all of the weird differences between how they cook and how other more classic cooking methods work.

We're taught that heating has three styles: convection, conduction, radiation. But AFAIK, microwaving is a fourth and distinct style.

*: Even more specifically, they add rotational momentum to these molecules, which is not the same as heat, but gradually turns into heat (which is translational momentum) as they knock around. This, in addition to the fact that only the water is being heated, and that the microwave waves touch the food in an uneven pattern even if mitigated by a rotating platter, is why stirring or waiting or using "low power" (dithered) is an important part of microwave recipes, as well as why high moisture foods or intentional steaming works so much better in it

firesteelrain3• 2 years ago

Microwaves also affect other polar molecules and ions in food, not just water.

This excitation leads to the generation of heat, which is then transferred through the food via conduction.

Microwaving is indeed considered a form of dielectric heating, which is a subtype of radiation. It’s distinct from conduction, convection, and traditional infrared radiation but still falls under the broader category of electromagnetic radiation-based heating.

bsder• 2 years ago

Microwaves also affect other polar molecules and ions in food, not just water.

So why does sugar seem to heat so preferentially?

I always found that microwaving any dish with a "syrup" made it the temperature of hot lava while the rest of the dish was still cold.

sadhorse• 2 years ago

Microwave heating is not a fourth form of heat transfer as it name implies: microwave radiation. Yes, the heat is not being radiated by a thermal source of microwaves, but it is radiation being absorbed. Hence radiation is the mechanism.

Rotational momentum is also heat as it is kinect energy related to movement, linear or not.

galdosdi2• 2 years ago

I'm speaking from a practical cooking perspective, not a technical physics perspective. The radiation from flames or the sun affects food very differently than microwaves do.

For the same reason, I probably messed up other physics technicalities. It would have been nice if I added a caveat I guess, but so it goes. My mental model may be simpler than the truth, but it's a lot better for achieving practical results in the kitchen than nothing than "microwaves heat stuff up fast", which is what I had before and is a really shit model that fails to explain most of their odd behavior.

HPsquared2• 2 years ago

I suppose there's nothing stopping other forms of radiation like the visible spectrum. How about intense blue light? Could it penetrate better than microwaves?

datameta• 2 years ago

Due to the higher frequency it wouldn't penetrate as well. But it is fun to think about the other EM sources used for cooking.

throwaway342kk• 2 years ago

https://news.ycombinator.com/item?id=29042728

Symmetry• 2 years ago

According to the researchers, the findings underscore the importance of regularly cleaning microwaves to reduce potential health risks, particularly in environments where food is handled.

Does that follow? I'd expect that as organisms adapt to environments that diverge further from the inside of your body they also become less dangerous, all things being equal. But then again I'd never heard the idea that microwaves are sterile inside and given the standing waves inside I would have dismissed it.

creesch• 2 years ago

I am also wondering how resilient these organisms are in the food matter we are heating up once it is heated up to certain temperatures. I guess that also means I am wondering how much of these organisms are airborne or are just living on the surfaces of the microwave without ever coming into contact with my food.

Having said that, one thing I regularly do is just place a bowl of water in the microwave with a bit of lemon juice (optional). Put it on for a very long time, so that is boiling for several minutes. Then wipe off the surfaces.

throwup238• 2 years ago

I am also wondering how resilient these organisms are in the food matter we are heating up once it is heated up to certain temperatures.

I can't find the FDA food safety table right now but IIRC 12 minutes at 140F, 1 minute at 165F, or less than 10 seconds at 185F is enough to kill off everything except endospores.

adrianN• 2 years ago

Unless we have data that shows that people get sick from unclean microwaves I don't think you can conclude that they pose a health risk, no matter what bacteria you find inside.

charlie04• 2 years ago

Because so many people don't have the common sense to cover their food when they heat it up. A microwave is the worst thing to have in a college dorm. Guaranteed filth to be covering the inside.

It also doesn't help the default power is set to 100%, causing volcanic like explosion of anything with high amounts of moisture, like tomato sauce. God save your tongue on taking a bite out of a Hot Pocket that's been in there too long. You swear there's lava in the thing.

People just don't really know how to use microwaves.

the__alchemist2• 2 years ago

I blame the UI. IMO should be two knobs and a button. (Maybe you just push one of the knobs instead of the button)

andrewshadura• 2 years ago

WDYM, but it is two knobs and a button?

charlie04• 2 years ago

Yes, something like changing the power levels normally require pressing of multiple buttons. Many menus and options are also hidden that way. Unfortunately, the true potential of a microwave is locked away. Pretty much everyone I know just hits the 30 second button and is content with super hot or unevenly heated food.

KineticLensman• 2 years ago

Presumably Duration, Power and Start/Stop. My NEF microwave has a Duration dial, 6 different power buttons (presets for 900, 600, 300, etc) and separate Start and Stop buttons. Oh, and another small button for forcing the Duration dial into a clock setting mode (to set the time-of-day display which is the default when the thing isn't heating).

Works okay, quite intuitive, entirely used to it now.

Just don't get me started on the controls for my induction hob

exe34• 2 years ago

yes! mine's like that, two knobs: one for how hot and the other is for how long. it's the dumbest one I could find and I'm never buying one with WiFi, thank you very much!

adrianmonk• 2 years ago

IMO, for prepackaged foods like frozen dinners, the UI should be that you put the food in the oven and close the door, and the microwave figures out the rest. (Of course there would also be manual controls available.)

The simplest way would be with a barcode on the plastic food tray. The barcode would contain the actual cooking instructions so that there's no internet dependency.

rebuilder• 2 years ago

Two knobs will do. The timer knob can be used to stop the microwave and it starts once the timer is set and the door is closed.

formerly_proven• 2 years ago

People just don't really know how to use microwaves.

Usually don't care, not don't know.

HPsquared2• 2 years ago

The two factors mutually reinforce each other.

overstay8930• 2 years ago

Most microwaves are terrible too, good microwaves are much more expensive so nobody buys them, but they can cook much more intelligently with higher quality parts.

goda90• 2 years ago

I've been dreaming of buying an inverter microwave(the inverter allows it to put out lower intensity microwaves to achieve lower power levels instead of just turning them on and off entirely like most microwave ovens), but for some reason the market for them is tiny. The kind I need, over-the-range inverter microwaves with ventilation, isn't even sold in the US. Strangely enough it is sold in Canada, which has the same electrical outlets. I might do a road trip to buy a microwave...

Brian_K_White4• 2 years ago

The only purpose a microwave serves in the first place is to heat as quickly as possible, and coffee and popcorn and hot pockets etc are not made any better by going slower. It is perfectly reasonable for the default to be 100%.

It doesn't matter that you can produce a nicer result by going slower. You can also produce a nicer result by using a regular oven and fresh ingredients.

The defined purpose of a microwave is to serve a different priority. A microwave with any other default is a dull saw blade.

abeppu2• 2 years ago

Time for a combined microwave oven / UV sterilizer to enter the market?

dukeofdoom• 2 years ago

Sound like million dollar idea buddy

CatWChainsaw2• 2 years ago

Engineering or sales?

nxobject• 2 years ago

How about a UV oven?

abeppu2• 2 years ago

Oven-shaped UV sterilizers exist, but I think bc UV really gets stopped at the surface, it would be really ineffective as an oven in the sense of cooking anything?

roughly• 2 years ago

Everywhere is a haven for bacterial diversity. Bacteria outnumber human cells in your body 10:1.

postalrat• 2 years ago

What harm is this causing? Are people getting sick?

OutOfHere3• 2 years ago

IMHO the harm is more likely from lids that are reused to cover food. If these lids are not routinely dishwashed like other utensils are, then by extension, they are likely to harbor bacteria and maybe even risk passing some into food. These lids are a lot closer to the food than the walls of the microwave. Indeed this could make people sick even if the microwave itself doesn't. Dishwashing the lid is paramount.

Brian_K_White4• 2 years ago

That is a theory or hypothesis, but the question is, does this theoretical harm actually exist? Are there actually significant numbers of people harmed by this mechanism? It might be but they don't show that.

shaneofalltrad• 2 years ago

I once had a baby spider living in the bottom corner of my microwave that I used about 5 or so times before it finally died. That's when I realized my understandings of microwaves was a bit cold in the edges.

igtztorrero• 2 years ago

Wow an article from my alma mater top to HN wow congrats folks!

Microwaves: A Haven for Bacterial Diversity

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