ELI5 Defrosting - what is the 'danger zone' and why does it matter?

What is the danger zone when talking about food safety? Can we leave meat in hot water or at room temperature to defrost it? If bacteria die from heat or say, boiled water, where do their corpses go? What is depyrogenation?

... we explain like I'm five

Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: haerveu, chel_of_the_sea, admiralteal, doItsarahlee, wikiwantsyourpics, all_work_all_play and breezingby56

To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter:

https://www.twitter.com/eli5ThePodcast/

or send us an e-mail:

ELI5ThePodcast@gmail.com