The trend in America of adding probiotics, or beneficial bacteria, to processed foods could continue, provided manufacturers add enough of them to produce a physiological effect in consumers, said Dr. Mary Ellen Sanders, a consultant with Dairy and Food Culture Technologies, Centennial, Colo.
"This is an exciting time for this area," Ms. Sanders said. "But if products on the market are not formulated responsibly, there will be a peak in sales and then people will quit being interested."
She added, "This could be just another dietary fad that people walk away from."
One product containing probiotics has scored big with consumers. The Dannon Co. introduced its Activia yogurt this year in the United States, where sales surpassed $95 million by Oct. 8, according to Information Resources, Inc. The sales covered supermarkets, drug stores and mass merchandise outlets, excluding Wal-Mart.
Ms. Sanders, who has a Ph.D. in food science from North Carolina State University in Raleigh, helps food and supplement companies develop new probiotic products. She said depending on the specific strain, consumers may need to eat as many as 1 billion bacteria cells per day for them to have a physiological effect. If a company skimps, such as by adding 100 million when 1 billion are needed, it would not be a meaningful amount.
The Food and Drug Administration allows for structure function claims in the case of probiotics sold as foods or dietary supplements, she said. For example, a company may say the probiotics in a product help a body’s natural defense system if the claim is truthful and not misleading. She said she knows of no case involving probiotics where the F.D.A. has asked companies to provide evidence-based research that supports structure function claims.
No legal definition exists for probiotics, Ms. Sanders said. The World Health Organization follows the definition of probiotics as "live microorganisms which when administered in adequate amounts confer a health benefit on the host."
Probiotics from the Lactobacillus genus and the Bifidobacterium genus are used most frequently in the food industry. Different species exist within each of the genera.
Selecting which strain to use will depend on what type of claim the company wants to make. Claiming a product promotes a healthful digestive tract will require data that supports this statement, Ms. Sanders said. For example, Dannon’s Activia yogurt contains Bifidus Regularis to aid in internal transit time, or the movement of food through the digestive tract.
The price of a probiotic strain likely will be higher for a strain with more research documentation of efficacy, Ms. Sanders said and added more probiotic information can be found at www.usprobiotics.org. Chr. Hansen, Milwaukee, said its BB-12 Bifidobacterium, LA-5 Lactobacillus acidophilus and L. casei 431 are three of the most scientifically documented strains in the world.
According to Dairy Management, Inc., Rosemont, Ill., probiotics may be applied in products as a culture added to a food, as an inoculation into a milk-based food or as concentrated and dried cells packaged in dietary supplements.
Dairy products may be ideal carriers of probiotics for several reasons, according to D.M.I. Dairy products buffer the high acidic environment in the human stomach to create a more favorable environment for probiotic survival. For another reason, many dairy products are refrigerated and have a short shelf life. Ms. Sanders said probiotic strains need to be present throughout a product’s shelf life.
Baking probiotics kills them, but Institut Rosell, based in Montreal and a subsidiary of Lallemand, Inc., still wants to find successful applications of probiotics in grain-based foods. Institut Rosell’s research involves adding probiotic strains in the post-baking applications of pastry custard, cream cheese, cheese spread, chocolate, praline, peanut butter and cookie cream filling.