"It is unfortunate that products currently can be labeled as probiotics but be neither well defined nor substantiated with controlled human studies," states the report. Based in Iowa, CAST is an international consortium of 38 scientific and professional societies with the mission of filtering and communicating science-based information back to regulators, policymakers, industry and the public. As part of the report, Probiotics: their potential to impact human health, the authors reviewed scientific literature on the friendly bacteria stemming from both the US and internationally. Led by task force chair Mary Ellen Sanders, from Dairy and Food Culture Technologies in Centennial, Colorado, the authors reported the pace of research into probiotics has accelerated in recent years as the market share of these ingredients has also risen. More than four times the number of human clinical trials on probiotics were published during the period from 2001 to 2005 than from 1996 to 2000, said the researchers. However, they also said there are significant gaps between what research has shown to be effective and what tests of products actually are on the market have revealed. "Documented failures of products to meet label claims with regard to numbers and types of viable microbes present in the product and how many must be consumed for a health benefit suggest that there is a problem in the probiotic industry with regard to accurate labeling," wrote the authors. Probiotics are beneficial bacteria that promote gut health and immunity. While consumers in Europe and Asia have been aware of the concept of friendly bacteria for a long time, the nutraceutical concept has only recently begun to take off in the US. According to Euromonitor, the global probiotic spoonable market went from $1.7b in 2001 to $4.1b in 2006. Over the same period in the US, it went from $112m to $294m. The report documents challenges to delivering the right amount of probiotics to consumers. These obstacles include misleading labels and the use of inappropriate amounts or strains of probiotics - the overarching umbrella of both issues, the report indicates, is a loose regulatory environment for the products. "There is neither a legally recognized definition of, nor a standard of identity for, the term "probiotic" in the United States or worldwide," wrote the authors. "Products containing this label, therefore, currently are not obligated to meet any standards unique to probiotics." In 2002, a working group under the UN's Food & Agriculture Organization (FAO) and World Health Organization (WHO) established a set of guidelines for examining the scientific evidence on the functional and safety aspects of probiotics in food. The CAST authors suggest these guidelines should be the ones used as a starting point for governments to devise their own policy with regards to probiotics. The intention of the working group was not only to provide scientific advice on the safety of probiotics, but also as a "general guidance for their evaluation and on specific questions in relation to their pathogenicity, toxigenicity and allergenicity, as well as to their functional and nutritional properties", according to FAO. Probiotics are unique microbial ingredients in that they must be kept alive throughout formulation, packaging and distribution. Meanwhile, manufacturers must strive to meet consumer demand for taste, convenience and price. "These considerations are not trivial, and unfortunately not all products marketed as "probiotic" suitably address them," states the CAST report. A common occurrence highlighted in the report has been for yogurt manufacturers to list the genus and species of live bacteria on their labels. Even if the manufacturers make no health claims, say the authors, the implication from the consumer perspective is that these are value-added functional ingredients. As a solution, the authors suggests manufacturers label the genus, species, and strain for each probiotic in a product, along with the viable cells of each probiotic strain that will remain up to the end of shelf life. The authors anticipate opposition to this notion. "Some manufacturers resist this approach, claiming it confuses consumers," they wrote. The CAST report forecasts the number and types of products using probiotic ingredients will continue to increase across the food, dietary supplement and pharmaceutical categories. However, if regulations and awareness of efficacy issues tighten around the products, so too will the race to market more bioavailable probiotic functional foods and dietary supplements. "As competition intensifies in the marketplace, companies providing responsibly formulated and promoted products will prevail," wrote the authors.