ELI5 E. Coli - what is it and why isn’t it all bad?

What exactly is E. coli, and why should we care about it? Why is it used a lot in scientific research? What does E. coli pop up often in food contamination cases? What are the symptoms? What are some notable outbreaks? ... 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: pckman, jacksmith8001, coldpizzza4, mistercortez, cutegun, likesmoonpies and ehcksit 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