Would you eat food that fell on the floor? That’s the question Hannah and Dara are getting their teeth into this week as they put the so-called ‘5 second rule’ through its paces.

For some people it’s 3 seconds, and for others its 10 – especially if it involves a dropped ice cream and a screaming child. But microbiologist Don Schaffner says there’s no safe amount of time to leave food on the floor if you’re planning to eat it. And while you might think buttered toast would pick up the biggest number of bugs, it may surprise you to hear that wet foods like watermelon are actually the worst when it comes to attracting harmful bacteria.

If all this is putting you off your dinner, the bad news is that the rest of your kitchen is also a microbiological minefield. Research shows nearly 70% of us keep our fridges are the wrong temperature, which sparks a lively discussion about whether it’s ever safe to reheat rice.

For home hygiene guru Sally Bloomfield it’s all a question of being a bit more clever about the kind of germs we expose ourselves to and weighing up risks.

Contributors:

Dr Don Schaffner: Rutgers University
Dr Ellen Evans: Cardiff Metropolitan University
Professor Sally Bloomfield: International Scientific Forum on Home Hygiene

Producer: Marijke Peters
Executive Producer: Alexandra Feachem
A BBC Studios Audio Production