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About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.
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Where does bacterias in the fridge come from?

Tue Feb 21, 2006 9:55 pm

Example:
You put some food in the fridge and leave it there for a month. You transfer some bacterias over to the food via your hands. Fungus and bacterias starts to grow. What it I leave the food in the fridge for many years and heat up my fridge? Assume patogenic bacterias will grow then. Where does these come from then?


I understand that the food has some different bacterias in the first place, but it cannot contain all kinds of bacterias, can it?

Wed Feb 22, 2006 6:00 pm

Why do you think they can not contain all bacteria. I think they can. They come from soil, and soil contains nearly all bacteria. Am I wrong? Correct me please.

Wed Feb 22, 2006 6:07 pm

I agree with poison, bacteria in the fridge come from the food that is put in. Pathogenic bacteria are pretty common on food, but usually get killed during food prepartion. Another risk is that if your fridge is not clean, a few bacteria on your food can multiply and heavily infect the rest of the food.

But the lesson is be carefull to wash your food and what you use to handle it (including hands) when you are cooking.

Thu Mar 02, 2006 6:28 am

You can seal the container you put your food in and then heat it enough to kill the bacteria if you want. Then nothing will grow until you open it :)

Thu Mar 02, 2006 6:54 pm

There might be a small problem that you won't be able to eat most of the food afterwards...

Thu Mar 02, 2006 9:32 pm

It has to do with the abilities of bacteria. When the temperature is lowered, many bacteria can push most of their organelles out of themselves, then shrink and harden. When they are warmed up, they can return to their original states, and reproduce the organelles they lost. This means that no matter how long you leave the food in the fridge, the bacteria will remain (unless you want to wait until the genetic material starts to decay).

However, heating bacteria denatures the proteins inside of them, which destroys them very effectively.

Fri Mar 03, 2006 4:25 am

Khaiy wrote:It has to do with the abilities of bacteria. When the temperature is lowered, many bacteria can push most of their organelles out of themselves, then shrink and harden. When they are warmed up, they can return to their original states, and reproduce the organelles they lost. This means that no matter how long you leave the food in the fridge, the bacteria will remain (unless you want to wait until the genetic material starts to decay).

However, heating bacteria denatures the proteins inside of them, which destroys them very effectively.


Huuhhh Bacteria have no organelles per se. What you are talking about is sporulation, and not all bacteria can do that. And overheating (although moderate) and many other stresses can trigger it, in sporulating bacteria of course :-)
If you want to wait for decay of DNA, well good Luck, you probably die before that since some spores more than 2000 years old have been succesfully cultured.
And for the bacteria in your fridge they do not only stay on the food, but also on the walls of your fridge. So they can cross contaminate.
People at the french food security agency say that we should wash our fridges with bleached water every week. Storing food in closed containers by separating food also prevent cross contamination. Sterilization of food as suggested above could also be a solution, but is not always possible (steamed lettuce anyone? :-) )

Fri Mar 03, 2006 11:23 am

Nah, if you wanna free-bacteria (or at least minimally level of Bacteria) just irradiate your food or get it into autoclave for half an hour before you start eating it...:lol:

Fri Mar 03, 2006 2:06 pm

Wash my hands and equipments. Ok.

sporulation trick! yes those bacts that have more sporulation during mostly used heating processes would have been naturally selected...

And those who can reappear when out of fridge, will also be. So don't worry u have plenty of bacteria to eat!!!

WHy don't we eat heated bacteria soup or fungus cake[ like mushrooms] ,
Does anybody knowabout the bacteria used as food?

Fri Mar 03, 2006 6:33 pm

Maybe you can try what my mom does: wrap your food in plastic foil, you can find it at the market. It keeps food isolated from one another.
Also, i saw a fridge at a friend of mine's house that said "Antibacterial fridge" on it. Donno how it works... Maybe it autoclavates the food like victor said

Fri Mar 03, 2006 7:54 pm

MrMistery wrote:Maybe you can try what my mom does: wrap your food in plastic foil, you can find it at the market. It keeps food isolated from one another.
Also, i saw a fridge at a friend of mine's house that said "Antibacterial fridge" on it. Donno how it works... Maybe it autoclavates the food like victor said


Yeah isolating different foodstuff from one another and from the fridge is the way to go. Be it with boxes, plastic wrap bags or whatever.
Autoclaving is not the only way to sterilize, and as I pointed out, in terms of cooking its far from being the ultimate solution (yummi autoclaved fruits..., not good for vitamins either). Using an ionization device is probably a bit difficult at home. So isolation is the easiest.

Antibacterial fridges includes some metals in the plastic that reduce the ability of bacteria to survive. I think Silver ions are generally used. But I have no idea of the exact antibacterial effects of metal ions of bacteria. Shame on me.

Sat Mar 04, 2006 7:51 am

I saw at the supermarket that they are selling bandages now with silver in them to help prevent bacterial growth. I think this use to be popular a time ago and they are bringing it back now. And I know that certain burn creams that hospitals use have silver in them to protect new skin from infection.

There was also this story about a senator that drank some silver concoction to stay healthy and it turned him blue!!! haha, it was permanent too! One of our profs said that too much silver and the body cannot get rid of it, and what is laying close to your skin will become photoactivated by sun and turn you blue.

And people used to use heavy metals like mercury and arsenic to prevent bacterial diseases, but they are so toxic that they did just as much damage to body as to bacteria!!

I think I will stick to standard antiseptics and disinfecants for my body haha :)
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