Researchers develop surface coating to reduce food contamination risk

In the future, a durable coating could help keep food-contact surfaces clean in the food processing industry, including in meat processing plants, according to a new study from a team of University of Missouri engineers and food scientists.

The study demonstrated that the coating – made from titanium dioxide – is capable of eliminating foodborne germs, such as Salmonella and E. coli, and provides a preventative layer of protection against future cross-contamination on stainless steel food-contact surfaces.

“I knew that other researchers had developed antimicrobial coatings this way, but they hadn’t focused on the coatings’ mechanical resistance or durability,” said researcher Eduardo Torres Dominguez. “In the presence of ultraviolet light, oxygen and water, the titanium dioxide will activate to kill bacteria from the food-contact surfaces on which it is applied. Although the coating is applied as a liquid at the beginning of the process, once it is ready to use it becomes a hard material, like a thin layer of ceramic.”

Heather K. Hunt, an associate professor in the College of Engineering and one of Dominguez’s advisors, guided Dominguez through the process of finding, selecting, synthesising, and characterising the titanium dioxide material – a known disinfecting agent that is also food safe.

“We picked this material knowing it would have good antimicrobial behaviour, and we strengthened its mechanical stability to withstand normal wear and tear in a typical food processing environment,” said Hunt. “In addition to normal cleaning procedures, our coating can add an additional layer of prevention to help stop the spread of foodborne contamination.”

Once Dominguez developed the coating, Azlin Mustapha, a professor in the College of Agriculture, Food and Natural Resources’ Food Science programme and Dominguez’s other advisor, helped him to optimise its antimicrobial – or disinfecting – properties. Matt Maschmann, an assistant professor, then focused on optimising the material’s durability through hardness testing.

“This will not only be helpful in the raw food processing lines of a processing plant but also ready-to-eat food lines, like deli counters, as well,” Mustapha said. “All surfaces in a food processing plant that come into contact with food are prone to be contaminated by foodborne germs spread by the handling of a contaminated food product.”

The researchers said this is the first step needed toward future testing of the coating’s properties in a real-world environment. Although the team has not tested it for use against the novel coronavirus, Hunt and Mustapha believe their coating has the potential to aid in helping stop the spread of the COVID-19 pandemic in a food processing environment because of its durability and disinfecting qualities. So far, it has shown to be effective against a strain of E. coli that can be deadly in people, and more work is being done to test the coating against other disease-causing bacteria.