Durable coating to keep food contact surfaces clean

In the future, a durable coating could help keep food contact surfaces clean in the food processing industry. The coating could not only be helpful in the raw food processing lines, such as meat processing plants, but also ready-to-eat food lines, such as deli counters.

A team of University of Missouri engineers and food scientists have demonstrated in a study 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. The team also believe their coating has the potential to aid in helping stop the spread of the COVID-19 pandemic in a food processing environment.

The study was conducted by Eduardo Torres Dominguez, who is pursuing a doctorate in chemical engineering in the MU College of Engineering, and includes a team of researchers from the College of Engineering and the MU College of Agriculture, Food and Natural Resources. Dominguez is also a Fulbright scholar.

“I knew that other researchers had developed antimicrobial coatings this way, but they hadn’t focused on the coatings’ mechanical resistance or durability,” Dominguez said. “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,” Hunt said. “In addition to normal cleaning procedures, our coating can add an additional layer of prevention to help stop the spread of foodborne contamination.”

Making the coating. Image credit: University of Missouri.

The researchers said this is the first step needed towards 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 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.

The study, ‘Design and characterization of mechanically stable, nanoporous TiO₂ thin film antimicrobial coatings for food contact surfaces’, is available here: http://dx.doi.org/10.1016/j.matchemphys.2020.123001.

Top image credit: ©stock.adobe.com/au/Dmitry Vereshchagin