All-Pro Probiotics

You know bacteria has hit the big time when U.S. television commercials tout the benefits of regularity, digestive heath and immunity, topics that arent typically talked about, even among close friends. The products these ads are touting are yogurts, and the bacteria they are referring to are probiotics. Probiotic means for life, which refers to their positive effect on health. We all have probiotic bacteria in our intestines that assist with food and nutrient digestion, inhibit harmful bacteria and viruses, and stimulate the immune system. Dietary probiotics replace the intestinal organisms lost to antibiotic use, disease, poor diets, stress and other factors.

Straining the science

The typical yogurt cultures are Lactobacillus bulgaricus and Streptococcus thermophilus. They are lactic-acid bacteria used to start the fermentation process in fermented milks like yogurt. The probiotic bacteria often used in yogurts are Lactobacillus acidophilus, bifidobacteria and Lactobacillus casei, but more than 30 strains of probiotics are on the market today. Lactobacillus acidophilus is the most consumer-recognized strain of probiotic on the market; therefore, it is requested the most and is usually the primary ingredient in custom blends, says Tim Gamble, vice president, Nutraceutix, Inc., Redmond, WA.

The probiotics most often utilized in studies include Lactobacillus. acidophilus, Lactobacillus reuteri, Lactobacillus rhamnosus, Lactobacillus salivarius, Bifidobacterium bifidum and Bifidobacterium infantis, according to Gamble. A probiotic strain is listed by the genus, species and an alphanumeric designation.

Bifidobacterium lactis BB-12 is one of the mostdocumented probiotic strains on the market, says Mirjana Curic-Bawden, Ph.D., senior scientist, Chr. Hansen, Milwaukee.. There are more than 160 scientific publications including well-designed clinical studies that used BB-12 as a single strain or in combination with other strains, mostly Lactobacillus acidophilus LA-5.

BB-12 and LA-5 have well-established documentation showing beneficial effects on preventing of travelers diarrhea and reestablishing intestinal balance in children and in the elderly. Even though most clinical documentation shows a positive effect of probiotics in connection with a condition or a disease, or in combination with a medication or treatment, one should keep in mind that probiotics are food; they can help, but they are not designed to cure any disease, she says.

Lactobacillus paracasei F19 is another probiotic strain with numerous, well-documented health benefits. F19 is a patented strain that has the ability to improve digestive health, enhance immune system function and reduce the negative effects on GI well-being during antibiotic treatment, says Tom Wiersum, product manager, Medipharm USA, Des Moines, IA. In addition, more recent research indicates that F19 is able to induce satiety, metabolize body fat and reduce weight gain.

Culture claims

Currently, FDA has not approved any claims for probiotics. Consistent results of several well-designed, double- blind, placebo-controlled clinical studies that show positive effects on certain biological functions in the human body would allow a structure-function claim, says Curic-Bawden. In vitro and animal studies can be supportive, but are not considered sufficient to document structure-function claims. Structure-function claims must be supported by relevant clinical documentation for the particular strain or combination of strains. What is equally important is that the cell count of the particular probiotic strain present in the product at the end of shelf life has to be equal or higher than the levels shown effective in clinical studies, she explains. For example, the minimum effective daily dose of BB-12 is 1 billion CFU (colony-forming units), which is usually delivered in one serving.

Bacteria survival is key to the health benefits, so survival through a typical shelf life determines usage rates. Some strains, like Lactobacillus reuteri, are strict anaerobes with very low tolerance to oxygen, which limits their application in food. These would have to be processed, packaged and stored in a controlled environment, so they are typically used in dietary supplements. Other strains, like Lactobacillus casei and Lactobacillus rhamnosus, are also sensitive to oxygen. Having a good survival rate is important, but also make sure the probiotic does not negatively impact the flavor, texture or appearance of the final product.

New applications

Probiotics are showing up in milk, cheese, fresh pasteurized juices, ice cream, frozen yogurt, cereal and nutrition bars. Since probiotics are living organisms, viability is the key to success. Heat-treated foods, such as baked products and processed foods, are not good candidates. One way to add probiotics to a baked product is through a compound coating applied after baking. This will provide a low water-activity environment, and the fat will have an encapsulating effect and protect the probiotics. Ready to eat, single-serve products are good targets. All products containing probiotics should be refrigerated to maintain best viability. The shelf life of the product, whether it is a juice or a nutrition bar, will be shorter than a product without probiotics. A 35-day shelf life for a fruit juice and three to five months for a nutrition bar with probiotics is typical, says Curic-Bawden. Leveraging their benefits with other functional ingredients is also a good idea. Prebiotic fibers, antioxidants and/or polyphenols are good choices for this.

F19 is certified kosher, the only probiotic strain approved by NASA and is available in a microencapsulated form for long-term viability in harsh environments, says Wiersum. F19 can survive for long periods at ambient temperatures in high water activity conditions, making a variety of applications possible that previously would not have succeeded. F19 can now be added to cereals, bars, drink mixes, infant formula, confections and more.

Kimberlee J. Burrington is the dairy ingredients applications program coordinator for the Wisconsin Center for Dairy Research in Madison, WI. She received her B.S. and M.S. in Food Chemistry from the University of WisconsinMadison. She has 20 years of product-development experience with an emphasis on bakery, beverage and dairy product applications.