The consensus is expected to raise the bar for probiotics and benefit companies willing to invest in bacteria with documented science and high stability.
Foods and supplements containing probiotic bacteria have seen rapid growth in recent years and are worth some £135 million in the UK alone in 2004.
But a number of surveys in different countries have revealed that many of the products do not contain the number of bacteria stated on the label and are therefore unlikely to have the positive effect on gut health.
For example, in 2001 Robin Temmerman at the University of Ghent in Belgium found that only 20 per cent of 55 products surveyed contained all of the bacteria listed on their labels, and nine failed to contain even one of the probiotic strains listed.
According to both scientists and some probiotic suppliers, this situation has not improved much.
The problem is down to the difficulty in protecting probiotic bacteria until they reach the intestine, their site of beneficial action. The live organisms must survive processing, storage conditions and tolerate the acidic conditions of the human stomach before finally reaching the gut.
Many manufacturers currently use overages to ensure their products still contain the sufficient bacteria at the end of their shelf-life to meet label claims. But better options are available, says one company with new technology said to guarantee that bacteria are still live by the expiry date.
"We tested a number of supplements on the market and found very little probiotic activity," Diane Burgess, technical manager at Danish raw materials supplier Broste, told NutraIngredients.com.
The company, with annual revenues of around €120 million, has gained exclusive distribution rights in Europe to what it claims is the most sophisticated of the probiotic protection methods - the Duolac coating technology, licensed from Korean firm Cell Biotech.
The patent-pending technology involves freeze-drying the bacteria with a soy peptide coating, protecting it against moisture. A further polysaccharide coating increases the shelf-life of the dry form and extends the areas of application.
"Probiotics are so unstable, you couldn't possibly add them to normal foods but this technology allows companies to add them to juices, muesli bars as well as a range of dairy products and supplements," said Burgess.
The firm is already supplying supplement manufacturers in Germany and South Africa with Duolac probiotics. It is also in talks with four major food manufacturers, each active in different sectors, for use of the technology.
The price is "very comparable with the same strength of products available on the market," according to Burgess. "In addition, manufacturers can use less as they don't have to overdose to be sure of meeting their label claims."
Other probiotic suppliers like DSM have focused on identifying strains with high stability as well as adding coatings to protect their bacteria from moisture during processing and storage. Rhodia Food, now owned by Danisco, has licensed a new bacterial stabilisation system from the University of Wisconsin-Madison in the US, based on technology originally developed to stabilise enzymes.
The European panel of microbiologists, immunologists and gastroenterologists not only declared the need for stability of bacteria but also said the bacteria should have clinically proven health benefits demonstrated using randomized, double-blind and placebo-controlled designed trials, and be clearly defined using 'modern biological detection methods'.
The probiotics should be clearly labelled, including the genus, strain and amount and be shelf-stable to guarantee the ingestion of the quantity of probiotic until the date of expiry.
"Claims for beneficial health effects of probiotics always need a solid basis," said panel member Professor Hamilton-Miller from the department of Medical Microbiology at the Royal Free and University College Medical School, London.
He told a Press Association report that it was not enough to say that products contained a probiotic organism. Companies need to define the exact type of organism because one strain of the same type may be beneficial and another may not.
"The consensus is a very welcome first step towards regulating probiotics and ensuring consumers really are getting positive strains with proven benefits and underlying mechanisms of effect," added Glenn Gibson, professor of Food Microbiology at the University of Reading.