[Janice Rabie]

Janice Rabie  asked the Naked Scientists:
   
Hi

I would like to find out about heating (re-heating) food and bad micro organisms developing.

I know you have talked about this on the radio, but I missed it.
Can you point me to something on your website about this?

Thanks
Janice

What do you think?

[cheryl j]

It isnt the re-heating per se. First, a particular type of bacteria has to be present, like a toxin producing Staph. Reheating just means the food has been kept longer and probably spent more time at a temperature the bacteria can grow at. The toxin produced by staph isnt destroyed by heat, so if its there, you are going to get sick.

Botulism is different. Its made by soil organism called Clostridium botulinum. This organism is harder to kill than most because it forms spores.  During canning, food needs to be boiled or pressure cooked longer than it normally takes to kill other bacteria.  Otherwise the botulism bacteria will grow inside the can because it likes an environment with little or no oxygen. But the good news is that it's toxin is destroyed by heat, so if you cook canned food, you you wont get sick, even if its contaminated. But some can foods arent cooked after opening (like three bean salad.) Tomatoes are usually a safe bet because they are too acidic for C. Botulinum, and pickles are too acid and salty as well.