UNIVERSITY PARK, Pa. — Gregory Ziegler, professor of food science in the College of Agricultural Sciences, recently received a grant of about $470,000 from the U.S. Department of Agriculture’s National Institute of Food and Agriculture to conduct a three-year study of alternative coatings for metal food cans.
“Billions of cans of safe food with extended shelf life reach consumers each year, contributing to food security,” Ziegler said. “Though the record of safety for canned foods is exemplary, consumers are demanding the elimination of BPA from can coatings. Consequently, BPA non-intent polymer coatings have been developed, and we are studying how best to deploy them.”
Scientists don’t use terms such as “non-BPA” or “BPA-free,” Ziegler explained, because they are not accurate. The term “non-intent” is used instead, which means that BPA is not part of the initial can. But because BPA is now present most everywhere and will take years to disappear from water, soil, crops and animal tissues, food processors can’t claim can linings contain no BPA.
But changing to new can coatings is proving to be difficult, Ziegler pointed out, adding that there is very little publicly available information on options to inform can-coating choices.
“The design and deployment of alternative coatings that can withstand the mechanical and thermal stresses imposed by can manufacturing and thermal processing is a major challenge,” he said. “BPA-containing epoxy does an exceptional job preventing corrosion of both steel and aluminum regardless of the food, beverage or processing method. Alternative coatings must not negatively affect public health and safety.”
The overall goal of Ziegler’s research is to reduce the potential for corrosion in canned foods employing BPA non-intent coatings, thereby extending product shelf life and improving food safety and security.
Because the novel coatings vary in their physical properties, the study calls for applying them on electro-tinplated steel and tin-free steel container materials. Ziegler then will use advanced materials-characterization techniques to evaluate the coatings’ resistance to aggressive food constituents, before and after thermal processing.
Ziegler lists three objectives for his research: Determine the corrosivity of food components/novel ingredients not previously identified as aggressive; determine the mode and rate of migration of aggressive compounds through the BPA non-intent coatings as a function of polymer properties; and establish the effect of the migration of aggressive compounds on the adhesion of the novel coatings to metal substrate and subsequent corrosion of the metal.
“The outcome of the study will be a fundamental understanding of the properties of polymeric coatings that protect the metal substrate and therefore the consumer,” he said.
Also involved in the research are Helene Hopfer, Rasmussen Career Development Professor in Food Science, and Elzbieta Sikora, associate teaching professor in engineering.
–Jeff Mulhollem, Penn State University