Do microwave ovens kill bacteria?

[Crazyhorse]

@jeffl

The question asks about pizza that has been sitting out for a while–not four hours, not 10 hours, but an ambiguous “while.”

The question was:

If I take a piece of pizza that’s been sitting on the table awhile and microwave it for one minute, would that kill bacteria and decrease the chance of food poisoning, or am I just eating nice hot bacteria?

The answer was yes, the heat from microwaving it sufficiently would kill at least some bacteria and therefore at least somewhat decrease the chance of food poisoning.

I don’t disagree that food poisoning by toxins could have been added as pertinent supplemental information. It is an important thing to consider in the general question of food poisoning and cooking, but the question was answered accurately in the frame of how it was asked. But the vast majority of food poisoning is caused by live bacterial infection or viruses. According to this guide there are only three species of bacteria that create toxins sufficient for causing illness without live bacteria.

Only three bacterial species are considered important causes of the intoxication type of food poisoning. These are Bacillus cereus, Clostridium botulinum and Staphylococcus aureus, all of which are capable of causing illness by producing toxins in food. There are several other species of Bacillus and Clostridium that have been reported to produce pre-formed toxins in food, such as B. licheniformis and Cl. butyricum, but these are uncommon and not considered further here.

Out of those three, about half of the toxins they might produce are not heat-stable and the toxin would be neutralized by cooking heat. But you are correct that out of those few toxins remaining that are heat-stable (among the thousands of other ways one might get food poisoning) their mere presence on the pizza pie in question would make the questioner sick even after being heated.