Have you looked inside your water bottle? I was shocked and disgusted by what I found in mine | Arwa Mahdawi

A reusable stainless-steel and silicone water bottle can become difficult to clean because of gaskets, straws, and components that may not fit in a dishwasher. When cleaning is infrequent, residue and moisture can allow mould to build up inside the bottle and straw. Flavoured electrolytes can further feed bacterial growth. A person who delayed cleaning discovered mould inside the bottle and experienced concern about possible diseases after noticing mould in their system. The person’s partner had previously urged more frequent bottle washing and reacted unsympathetically to the alarm. The experience led to learning that many other people find their bottles similarly filthy and should inspect and clean them regularly.

"What with the gasket and the straw and the various bits you couldn't stick in a dishwasher, it was a faff to wash. So I wasn't very diligent about cleaning it. After all, it was just water inside, right? And water's clean, right? I had put flavoured electrolytes in it a couple of times, but I didn't think much about the fact that they are a tasty meal for bacteria."

"Until last week, that is, when I decided to do some deep-cleaning. I stared into the abyss of my water bottle and a terrifying amount of mould stared back at me. Mould was in the straw, in the bottle and in my insides. I am not particularly squeamish, but I squeamed. And then I started furiously Googling what sort of diseases I'd inadvertently given myself while hydrating with mould water."

"My wife, who has told me many times to wash my water bottles more often, was not particularly sympathetic when I started squealing in horror by the sink. She was even less sympathetic when I said I was going to do the world a great service and inform everyone that they should inspect the insides of their water bottles stat. Through my Googling, I had discovered that plenty other people had been shocked by how filthy water bottles can get."

"Please don't write about this, my wife said. People will think you are gross and quite stupid. Serious"

Read at www.theguardian.com