Researchers Develop Hygienic Coating for Produce Storage Containers That Repels Bacteria, Fungi, Dirt

Researchers from Texas A&M University College of Engineering created a coating for galvanized steel food containers that repels bacteria and fungi, is mud-resistant, and reduces the risk of corrosion. The two-step coating technology can potentially be applied to grain storage silos, as well as other food storage units and containers, increasing postharvest food safety.

The coating was created through a two-step process involving the immobilization of silica nanoparticles, and the subsequent chemisorption of an organosilane layer with low surface energy. The resulting solution exhibits super-hydrophobicity and antifouling capabilities.

Galvanized steel containers and surfaces are used for harvested produce because of their durability, strength, and lower cost compared to stainless steel. However, bacteria residing in storage containers can cause corrosion. The new coating is able to reduce corrosion by at least 70 percent.

Additionally, the coating demonstrated the ability to decrease bacterial strains over a 7-day period, as well as to reduce surface adherence to Aspergillus, a foodborne fungi that poses a large food safety threat due to the production of carcinogenic aflatoxins. With use of the coating, adhesion of Salmonella and Listeria was also reduced by more than 99.5 percent.

Mud is another contaminant that is addressed by the coating technology. Harvested produce enters processing along with soil, debris, or mud from the field, and with this dirt comes microbial hazards. Following immersion in mud, surfaces coated with the new solution showed a significant reduction in mud attachment when compared to uncoated steel surfaces.

The project was supported by a Food Manufacturing Technologies Program grant and Specialty Crop Research Initiative grant from the U.S. Department of Agriculture’s (USDA’s) National Institute of Food and Agriculture.