Dairy Foods & BeveragesIngredients for Dairy ProcessorsDairy Foods ColumnistsButterCheeseIce Cream/NoveltiesPrebioticsProbiotics

An introduction to probiotics

Probiotics are friendly microbes that safely enhance nutritional value in dairy products.

By Pratishtha Verma

drinking probiotics — *Photo courtesy of Jupiterimages on gettyimages.com*

Pratishtha Verma is a research and development scientist at Idaho Milk Products (IMP). In her current position, she is working on various milk ingredient applications aimed at increasing the protein load as well as developing new application areas for IMP’s milk ingredients. Before joining IMP, Verma graduated from South Dakota State University, where she completed her master’s in Dairy Manufacturing with a concentration in dairy microbiology and food technology.

We generally think of bacteria as harmful germs that cause illness. However, our body contains two different types of bacteria, both good and bad. Probiotics are made up of good bacteria and other microbes including yeasts that offer several health benefits when consumed or applied to the body. The International Scientific Association for Probiotics and Prebiotics (ISAPP) defines probiotics as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” In layman’s terms, probiotics are good for our digestive system and are believed to be gut friendly.

Current U.S. regulations for the use of probiotics are complex and largely depend on the intended use. Probiotics generally fall under food ingredients, dietary supplements, or drugs. There is no specific cell count level of the microbe that may guarantee health effects in a food product. However, 10⁶ to 10⁸ colony forming units (CFU)/g is perceived as adequate for reaping probiotic benefits. The most used probiotics contain species of genus Lactobacillus or lactic acid bacteria, and Bifidobacterium.

Probiotics are utilized in several dairy products, including fermented dairy beverages, yogurt, cheese, butter, cream, ice cream, and infant formula. In addition, probiotics can be incorporated into fermented or non-fermented dairy products. Adding probiotics to dairy products enables them to obtain unique quality characteristics such as improved aroma, taste, flavor, texture, and nutritional value, along with numerous health-promoting properties compared to nondairy products.

Ensuring the viability of probiotics is very important for the high efficacy of probiotic products. Probiotics encounter several stress conditions during food processing, storage, and gastrointestinal transit. Most probiotic strains are sensitive to oxygen and their viability is affected by the presence of oxygen in dairy products. Bifidobacterium species are anaerobic, and the oxygen toxicity results in a significant decline in the number of this probiotic in yogurt, fermented milk, or cheese during storage. Several processing steps involved in the processing of dairy products (e.g., the agitation and mixing steps) inevitably incorporate a high amount of oxygen in the product.

There are several ways to tackle the challenges related to probiotic viability through technological changes. For instance, selection of oxygen-resistant probiotic strains, the use of oxygen impermeable containers and by removing molecular oxygen through oxygen-scavenging. Probiotic supplementation at later stages of processing is employed to maintain viability in cheese. The addition of ascorbic acid has been reported to increase the survival of Lactobacillus acidophilus in yogurt. Another study showed that adding glucose oxidase to yogurt before fermentation resulted in a significant reduction of oxygen (69.02% to 86.03%) compared with the control. The addition of nutrients and prebiotics (non-digestible components) in dairy products also has been reported to enhance the viability of probiotics.

In conclusion, probiotics are friendly microbes for our digestive system. They may be easily and regularly consumed when added to dairy products because of the typical aroma, taste, and flavor of these products. The viability of probiotics is moderately compromised when added to dairy foods, but continuous research efforts are being made to meet this challenge.

Sources:

Probiotics: What You Need To Know | NCCIH (nih.gov)

Probiotics: What is it, Benefits, Side Effects, Food & Types (my.clevelandclinic.org)

Aljasir, S. F. & D’Amico, D.J. (2021). Probiotic potential of commercial dairy-associated protective cultures: In vitro and in vivo protection against Listeria monocytogenes infection – Food Research International, 149, 110699 (https://doi.org/10.1016/j.foodres.2021.110699).

Cruz, A.G., Faria, J.A.F., Walter, E.H.M., Andrade, R.M., Cavalcanti, R.N., Oliviera, C.A. & Granato, D. (2010). Processing optimization of probiotic yogurt containing glucose oxidase using response surface methodology. Journal of Dairy Science. 93(11), 5059-5068.

Gao, J., Li, X., Zhang, G., Sadiq, F. A., Simal‐Gandara, J., Xiao, J., & Sang, Y. (2021). Probiotics in the dairy industry—Advances and opportunities. Comprehensive Reviews in Food Science and Food Safety, 20(4), 3937-3982.

He, J., Li, W., Deng, J., Lin, Q., Bai, J., Zhang, L., & Fang, Y. (2022). An insight into the health beneficial of probiotics dairy products: a critical review. Critical Reviews in Food Science and Nutrition, 1-20 (https://doi.org/10.1080/10408398.2022.2090493).

Pimentel, T.C., De Oliviera, L.I.G. De Souza, R.C. & Magnani, M. (2021). Probiotic ice cream: A literature overview of the technological and sensory aspects and health properties. International Journal of Dairy Technology 75(1), 59-76.