Rubber bath toys often harbour high amounts of bacteria and mould, a new report has confirmed.

A study published this week by the Swiss Federal Institute of Aquatic Science and Technology, ETH Zurich and the University of Illinois revealed the iconic yellow duck or other floating rubber toys can harbour germs often linked to hospital-acquired infections.

In a video filmed last year, YouTuber Viva Frei decided to cut open one of his childrens' rubber bath toys to show the mould that had developed inside it.

"That black stuff is mould, in bath toys that children play with and sometimes drink the water out of," he warns.

The report found that up to 75 million cells of bacteria or fungus are present per square centimetre on a classic rubber duck.

While tap water alone does not cause bacteria growth, a mixture of bodily fluids, soap and the polymers on the rubber toys create a perfect environment for germs to thrive.

This is a life protein illustration as to why you should throw out those little bath rubber ducky toys from time to time… They develop black mould inside.