AOAC Announces New Microbiological Method for Detecting Cronobacter in Infant Formula

Rockville, MD, April 24, 2018: AOAC announces today a new microbiological method for Cronobacter in infant formula. This latest AOAC Official MethodSM is a highly sensitive and robust quantification method for analysis of Cronobacter, a bacterium that causes food poisoning, and possible infection, that occurs most often in infants.

Most cases of Cronobacter (formerly known as Enterobacter sakazakii) come from dry foods, such as powdered infant formula, powdered milk, herbal teas, and starches, contaminated with the bacterium, and while Cronobacter infections are very rare, they can be deadly in newborns. Infections in infants usually occur in the first days or weeks of life. CDC is usually informed of about 4-6 cases a year.

“To help manufacturers eliminate Cronobacter from their factory products, new test kits are promising accurate, next-day results for the detection of Cronobacter spp.,” said Wendy McMahon of Mérieux NutriSciences, and co-chair of the AOAC expert review panel for microbiological methods for food and environmental surfaces. “One such kit, 3M’s MDA 2-Cronobacter, an isothermal DNA amplification and bioluminescence detection method, was rigorously reviewed by AOAC subject matter experts and has been deemed scientifically sound and suitable for intended use for infant formula.”

McMahon continued, “This expert decision is based on a comparative study of MDA 2-Cronobacter to a well-established culture method from the International Organization for Standardization (ISO 22964:2017) for the detection of Cronobacter species in powdered infant formula containing probiotics.” Technicians from 11 laboratories from the United States, Mexico, and Croatia had received test portions spiked with three levels of contamination. Statistical analysis indicated that the difference between methods at low inoculum levels was not significant.

Overall, the AOAC’s expert review panel agreed that 3M’s method is well written, comprehensive, and easy to follow. Study results are well documented. The method is rapid, specific, and sensitive. It provides results much more quickly than the traditional ISO method, where samples are cultured on agar plates.

The method was adopted as Official MethodSM 2018.01 and will be published in AOAC’s compendium of methods, Official Methods of Analysis of AOAC INTERNATIONAL.

“AOAC methods undergo rigorous scientific scrutiny and demonstrate the highest level of confidence in analytical results,” said DeAnn L. Benesh, president of AOAC INTERNATIONAL. “Our mission is to provide high-quality products and solutions for the analytical science community that are fit-for-purpose and recognized worldwide.”

AOAC INTERNATIONAL is a globally recognized, 501(c)(3), independent, third party, not-for-profit association and voluntary consensus standards developing organization founded in 1884. When analytical needs arise within a community or industry, AOAC INTERNATIONAL is the forum for finding appropriate science-based solutions through the development of microbiological and chemical standards. AOAC standards are used globally to promote trade and to facilitate public health and safety.

For more information, call (301) 924-7077 (worldwide) or (800) 379-2622 (toll free North America), visit, or contact Deborah McKenzie at AOAC is headquartered in Rockville, Maryland, USA.