New study: Kefir package claims don’t always accurately reflect composition of commercial products

Researchers reporting in JDS CommunicationsTM found overstated microorganism density and nonlabelled bacterial species, potentially misleading consumers

Philadelphia, May 12, 2021 – In recent years there has been an increased interest in the consumption of kefir, a fermented dairy beverage, because there is some evidence that it has health benefits and its affordability. A new study by researchers from the University of Illinois and The Ohio State University, published in JDS Communications, found that 66 percent of the commercial kefir products studied overstated microorganism density and 80 percent contained bacterial species that were not included on the label, potentially misleading consumers.

Senior author Kelly S. Swanson, PhD, University of Illinois, Urbana, IL, USA, believes better quality control of kefir products is required to demonstrate and understand their potential health benefits. “It is important for consumers to know the accurate contents of the fermented foods they consume,” Swanson said.

Swanson and his team of researchers bought five kefir products from online vendors and stores in the Urbana, IL area and analyzed two lots of each. Although all five guaranteed specific bacterial species used in fermentation, the team found that no product completely matched its label. All products contained Streptococcus salivarius, and four out of five products contained Lactobacillus paracasei, although they were not included on the labels.

Caption: This study analyzed five commercial kefir products and revealed inaccuracies of label claims that are of great importance to everyday consumers (Credit: B.N. Metras, M.J. Holle, V.J. Parker, M.J. Miller, and K.S. Swanson).

According to Dr. Swanson, classification as a “cultured milk product” by the FDA requires disclosure of added microorganisms. “Regulatory agencies and consumers must continue to scrutinize these products and demand a higher level of accuracy and quality,” he explained.

The authors hope this and future studies will call attention to the effect of inaccurate kefir product labeling.

Notes for editors
The article is “Commercial kefir products assessed for label accuracy of microbial composition and density,” by B.N. Metras, M.J. Holle, V.J. Parker, M.J. Miller, and K.S. Swanson ( It appears in JDS Communications, volume 2, issue 3 (May 2021), published by FASS Inc. and Elsevier.

The article will be openly available upon publication at

Full text of the article is also available to credentialed journalists upon request. Contact Eileen Leahy at +1 732 238 3628 or to obtain copies. Journalists wishing to interview the authors should contact the corresponding author, K.S. Swanson, University of Illinois, at

About JDS Communications
An official journal of the American Dairy Science Association®, JDS Communications is an Open Access, peer-reviewed journal that publishes short, concise original research in the form of short communications, technical notes, mini-reviews, and other scholarly works that relate to the production and processing of milk or milk products, derived from farm animals, intended for human consumption. Research published in this journal is broadly divided into animal production, physiology, health, and genetics and dairy foods for human consumption.

About the American Dairy Science Association (ADSA)
The American Dairy Science Association (ADSA) is an international organization of educators, scientists, and industry representatives who are committed to advancing the dairy industry and keenly aware of the vital role the dairy sciences play in fulfilling the economic, nutritive, and health requirements of the world's population. It provides leadership in scientific and technical support to sustain and grow the global dairy industry through generation, dissemination, and exchange of information and services. Together, ADSA members have discovered new methods and technologies that have revolutionized the dairy industry.

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Since 1998, FASS has provided shared management services to not-for-profit scientific organizations. With combined membership rosters of more than 10,000 professionals in animal agriculture and other sciences, FASS offers clients services in accounting, membership management, convention and meeting planning, information technology, and scientific publication support. The FASS publications department provides journal management, peer-review support, copyediting, and composition for this journal; the staff includes five BELS-certified ( technical editors and experienced composition staff.

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