Infant formula safety checks can be improved with stratified sampling, according to a new study from the Department of Food Science and Human Nutrition at the University of Illinois in Urbana-Champaign.
“Our lab had a prior project simulating bulk product sampling to improve food safety sampling plans for detecting aflatoxin in corn in bins and bacterial pathogens on leafy greens produce in fields,” Minho Kim, a PhD student and the study’s lead author, tells Food Quality & Safety. “We then wanted to adapt that simulation to bulk products, like powdered products.”
The authors found there was data available for Cronobacter in powdered infant formula produced in Europe in the 2010s, and chose to work on that problem. The subsequent outbreak and recall in the U.S. then provided additional relevance to the work.
Stratified random sampling is a pattern where you first pick an interval of time, e.g., every 10 minutes of production, and then take a sample randomly during each of those production intervals. “Sampling and testing play an important role in the HACCP plan by monitoring if the system is operating properly,” Kim says. “Thus, sampling plans should have enough power to detect pathogens of concern. There is an existing sampling guideline for testing Cronobacter provided by CODEX Alimentarius for powdered infant formula (30 samples of 10g); however, the sampling plan might not always work the same under different contamination profiles or production scales.”
Therefore, the researchers developed a web application for the sampling simulation tool that stakeholders can use to explore the power of sampling plans in different production lot and contamination profiles.
“Our major findings include that existing sampling guideline for detecting Cronobacter spp. in powdered infant formula products will be powerful enough to detect the contamination observed in a previously studied recalled batch from Europe, but not the non-recalled batch profile,” Kim adds. “By simulating different sampling plans with the recalled and non-recalled profiles, we were able to see the trend that taking more samples and adopting the sampling pattern with stratification help increase power to detect the contamination.”
A future discussion, he says, will be to investigate opportunities to reduce this residual risk in the powdered infant formula products. “A few babies getting sick from each outbreak cluster may represent the chance of this residual risk being problematic,” Kim adds. “One possible strategy is to use more active labeling on incorporating hot water reconstitution, like other countries [do]. A risk assessment done by WHO/FAO in 2006 showed that using 70°C water for reconstitution can significantly reduce the risk by inactivating Cronobacter sakazakii without damaging essential nutrients for babies. However, we heard about concerns from doctors in France where babies were coming to the hospital with burned throats. We hope more discussions about using hot water reconstitution between experts can lead to reduced Cronobacter illnesses.”