Parents are being warned to throw away a dental product used by children after tests showed it was contaminated by micro-organisms.

The Department of Environmental Health is advising against the use of the Glacier Mint and Bubble Blast flavours of Listerine Agent Cool Blue — a plaque-detecting rinse.

The product was launched last year and tints plaque blue, highlighting it to encourage better dental habits among children.

Despite no reports of consumer health problems, consumers are being advised to discard the Johnson & Johnson product. It should also be removed from all store shelves.