Dental scientists have claimed to have discovered a way to prevent bacteria that causes tooth decay from forming in the mouth.

BASF, the world's largest chemical maker, said its formula could be seen in toothpaste, mouthwash and even sweets as early as next year.

Using a micro-organism related to those used in yoghurt cultures, the German-based company said it has engineered a process that clusters harmful bacteria in the mouth before they can bind with sugar and form plaque.

The organism and plaque-causing bacteria are then swallowed as part of the mouth's natural cleaning process.

It is safe to swallow the bacteria, known by the scientific name Streptococcus mutans, because it is regularly found in the mouth and humans already digest it constantly, the company said.

"There is a complex dynamic of bacteria that grow on the teeth," said the University of Connecticut's Jason Tanzer, who studied BASF's results and presented his findings at an industry conference on Thursday. "They can stick to those surfaces and form a film or they can be swallowed."

As part of his study, Dr Tanzer fed two groups of rats a diet high in sugar, but put BASF's product, known as pro-t-action, in only one group's food.

Tooth decay in the group of rats using pro-t-action was far less pronounced than in the group not using the product, a development that Dr Tanzer said was promising. "I would be rather optimistic about this product," he said.

The active organism in pro-t-action is effectively dead, meaning it does not need to be kept cool -- like yoghurt -- and can be used in a wide array of products like sugar-free sweets, gum, toothpaste, and possibly drinks such as smoothies. To be effective, the product needs to be in the mouth for about 10 to 15 seconds.

"This is not a replacement" for brushing, said Markus Pompejus, a BASF scientist who helped develop the product. "But it clearly helps to improve your daily oral hygiene."