Steve.
I was very put off by imagining a water bottle with visible signs of faecal matter on it
. Took a day or so for me to scorch it from my mind. I would think he just didn't wash the bottle properly when washing hands after poo & some faecal traits, detectable by microscope, were left.
A lesson to him to not only wash hands with soap but bottle needs thorough washing too. Plenty of people only rinse hands after toilet rather than thoroughly washing, it's probably no more than that but newspapers make a deal out of it. Embarrassing
.
Hopefully he will move on, business intact.