"Wash your hands" is a commandment our parents instill in us from childhood, but call it teenage rebellion or hygienic apathy - not all of us do it. For further evidence, spend five minutes in a public washroom.
As of this week, Public Health England (PHE) is supporting the World Health Organization’s Clean your Hands campaign by showing up all those invisible germs that stay on the hands after using the loo or cutting up meat, and then - shockingly - the bacteria left behind even after we've washed them.
Why is it important? Our hands play a key role in spreading bacteria and viruses.
The more germs there are, say PHE, the greater the chance they will cause an infection.
Dr Paul Cosford, director of Health Protection and Medical Director at PHE, said: "It is quite shocking to see just how many bacteria we get onto our hands from doing everyday tasks. If we don’t wash our hands properly then just one bacterium can grow into hundreds and thousands in a relatively short space of time.
"These are then spread around our environment and onto other people and so on. This is why it is so important that we wash our hands thoroughly particularly before preparing food, after handling raw meat and after going to the toilet."
Although the pictures show that bacteria still remains after washing, the pictures also show the effectiveness of washing your hands after using the toilet.
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PHE says: "They cause illness by what in scientific terms this is called the ‘faecal-oral’ route of transmission. This is where we touch surfaces and then put our hands, and the bugs - including ones that are found in human faeces - into our mouths.
"Bacteria from faeces are spread around when people don’t wash their hands after using the toilet, changing nappies, handling cat litter and similar activities."
Peter Hoffman, an expert in infection control at PHE and the owner of the hands in the pictures, said: "Ingestion of these bacteria and viruses can cause a range of gastrointestinal and respiratory illnesses including E.coli O157, norovirus, colds and flu. It is also a way in which highly antibiotic-resistant bacteria can be spread around. These are increasingly being recognised as a major threat to public health."
For a guide on how to hand wash effectively, click here.