Probiotics' benefits, however, begin in the gut. Fermentation of indigestible carbohydrates provides short-chain fatty acids (SCFAs), the presence of which has been linked to reduced risk of inflammatory bowel disease, cardiovascular disease and certain cancers. SCFAs also reduce gut pH, which helps drive off pathogens and improve mineral absorption.
Most commercially utilized probiotic culture strains are of the genera Lactobacillus and Bifidobacterium, although there are addi-tional strains from other genera, including Escherichia, Enterococcus, Bacillus and Saccharomyces.
Typical dosage levels range from 5 to 20 billion CFUs per day. These levels do not necessarily reflect the amounts added to a food system, though, as processing techniques and conditions within the food can have a dramatic effect on the cultures’ ability to survive through shelf life.
One approach to ensuring proper levels at consumption is over-dosing. After studying the survival rate of the selected cultures in their product, processors can add an “appropriate excess” and ensure the required levels at the end of shelf life. However, “with probiotics, quality is more important than quantity,” says Mike Bush, vice president of business development, Ganeden Biotech, Inc., Mayfield Heights, OH. “If the cells are not able to survive to colonize the host, even huge doses are not going to make any difference. In order for probiotics to be beneficial to consumers, the bacteria have to survive the manufacturing process, shelf life in stores and the acid in the stomach so they can colonize in the intestines.”
Bush suggests a patented strain of Bacillus coagulans that actually protects itself. Due to the strain’s spore-forming nature, “it has the ability to survive through both high and low temperatures, high pressure and shear, and a variety of pH ranges and water activities,” he says. “It is stable in a large variety of manufacturing processes that would ordinarily kill most other probiotic organisms, has a long shelf life and can endure the acids in the stomach to proliferate in the small intestine.”
Improved stability and longevity open up many new application areas for prebiotics. “Traditionally, probiotics have been delivered in cultured dairy products,” notes Bush. “This is due mostly to the fact that traditional probiotics survive well in the safe, refrigerated con-fines of these dairy products. Due to its ability to withstand extremes, such as heat and cold, high pressure and shelf stability, we have clients formulating it into baked products such as: muffins and bars; heated products such as soup, coffee, tea and oatmeal; and frozen products such as frozen yogurt.”
Picky eaters
High dosage levels of the heartiest probiotic strains do not guarantee their survival or proliferation in the gut. “Probiotic chow” is a necessity, and it comes in the form of prebiotics. A special group of soluble fibers, prebiotic fibers, resist digestion and absorption in the gastrointestinal tract, are fermented by microflora in the gut, and stimulate growth and/or activity of at least one beneficial intestinal bacterium.