Work surfaces can be a breeding ground for bacteria

The most likely explanation, she says, is that toilet seats are simply too dry to support a thriving population of bacteria, which tend to prefer damp environments.

At the start of the study, reported in New Scientist, the researchers found a million times as many bacteria in the fluid wrung from dishcloths as on toilet seats.

Even chopping boards hosted three times as many bacteria.

Dramatic improvement

Towards the end of the study, the homeowners were given household bleach and advised on how best to use it. This resulted in a dramatic improvement in kitchen hygiene.

The number of bacteria coming out of the dishcloth went from 100,000 per millilitre of fluid to just 10.

Rubin's advice is to clean dishcloths at least once a week. "Simply add one cup of bleach to a sinkful of water, throw in the dishcloth and let it soak for 10 minutes before letting it drain," she said.

Worktops, sink surfaces, chopping boards and tap handles should be cleaned daily, and the toilet bowl three times a week.