Newswise — Washington D.C. – New research on powdered products safety checks shows that some methods are more powerful at catching contaminants than others.

A new study finds that spacing out samples over time, called “stratified” sampling, is better at catching risky pathogens like Cronobacter than randomly sampling from the product as it’s being produced. And that while taking more samples of product generally increases the chance to catch the pathogen, there is a point after which it is unlikely to increase safety very much.

Formula producers have comprehensive food safety systems that include control points like milk pasteurization and steps to prevent contamination such as sanitary facility design and regular cleaning and sanitation. Product testing is an additional tool producers use to verify these other systems are working. It is important that testing is powerful enough to catch a major failure before a potentially risky product is released to customers.

The new paper “Simulation Evaluation of Power of Sampling Plans to Detect Cronobacter in Powdered Infant Formula Production” was recently published in the Journal of Food Protection and was supported by IAFNS Food Microbiology Committee. This paper used computer models to simulate sampling and testing finished formula, to see the power of current national and international guidelines for testing programs, and how one could do better. 

All efforts were based on detecting a realistic hazard, here defined by what was observed testing samples from Cronobacter-contaminated batches produced in Europe in the 2010s, the most current data available. The paper found that safety plans with 30 or more grab samples had a very high probability of detecting hazards. And that there was a point of diminishing returns, such that very high sample numbers, like testing every can produced, would not be meaningfully more powerful.

According to project lead Matthew J. Stasiewicz at the University of Illinois Urbana-Champaign, “This shows that existing sampling and testing guidance is powerful, at least for the one hazard profile our team had access to for the study. This also highlights the need for additional research and data sharing efforts into patterns of contamination in current infant formula production, so that sampling and testing can be better matched to current needs.”

Lead author Minho Kim adds that “In additional to analyzing scenarios we found relevant, we built a web app that allows industry stakeholders to simulate various sampling scenarios and gain deeper understanding of the effectiveness of sampling plans specific to their plants. With this knowledge, producers can proactively address risks and optimize current sampling practices.” More information on the web app, including training materials, can be found by clicking here.

Additionally, for parents who are concerned about their infants getting ill from bacterial contamination of formula, the researchers advise they talk to their doctor about safer formula feeding. For example, one way to further reduce bacteria in formula is using hot water during reconstitution and then cooling it to body temperature prior to feeding. This simple preventative measure can greatly reduce the risk from Cronobacter contamination according to an international risk assessment from 2006. However, steps like this require care to avoid the risk of children being burned by the heated bottles.

The new paper can be found here.

The Institute for the Advancement of Food and Nutrition Sciences (IAFNS) is a 501(c)(3) science-focused nonprofit uniquely positioned to mobilize government, industry and academia to drive, fund and lead actionable research. This work was supported by IAFNS Food Microbiology Committee. For more information, visit

Journal Link: Journal of Food Protection

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Journal of Food Protection