For any product claiming to contain probiotic bacteria, "there have to be strain-specific studies on its health benefits," said Leporanta, who is in charge of marketing for Valio.

He gave a talk at September's Drinktec Expo on the growing market for probiotic juices.

Leporanta said a probiotic product should show scientific proof for its claims, must be clearly labeled and must meet health claim criteria in the relevant state.

At the moment, "even if a product doesn't meet these criteria it may still be called probiotic on the market," said Leporanta. "This is a difficult task for the industry. If I was the European Union, I would do something to stop this."

Valio, one of the first to develop a probiotic bacterial strain and use it in dairy product formulations, launched its first probiotic juice in 1997.