09 May 2017 The promise of new antibacterial metal surfaces in food-bev factories

A European team of researchers led by the University of Parma, inspired by the properties of the Lotus leaf, is developing what it claims is the first ever fluid‐repellent, antibacterial metal surfaces in the food and beverage industry.

Using laser technology develped by the EU-funded TresClean Project (High ThRoughput lasEr texturing of Self-CLEANing and antibacterial surfaces) it will produce machinery components which are sensitive to bacterial contamination, with plans to sell them commercially in two years.

The metal surfaces will initially be trialed on milk vats before expanding into other food areas.

Professor Luca Romoli, project coordinator, TresClean, said the project has received €3.3m ($3.5m) funding from the H2020 Industrial Leadership program and the Photonics Public Private Partnership Support.

“We are initially focusing on machine parts for the food industry to make a significant impact on productivity,” he said.

Lotus leaf inspired

Romoli added the team got the idea from Lotus plants where the leaves are fluid‐repellent and decided to replicate this in creating metal structures where, by reducing ‘wettability’, can form a barrier against bacteria.

He said TresClean creates ultrashort‐pulsed lasers to create a ‘surface topography’ on metal sheets to duplicate a Lotus leaf’s surface and prevent liquid adhesion.

The topography can capture miniature pockets of air that minimise the contact area between the surface and liquids.

“Lotus leaves keep themselves clean thanks to particular surface texture enabling water to stay as spherical droplets by preventing ‘spreading’,” said Romoli.

“Under these conditions, bacteria does not get a chance to stick because the contact with the metal surface and the liquid is reduced significantly. In this way, with laser technology it is possible to create an antibacterial topography on metal surfaces without adding chemicals.”

The process means manufacturers will spend less time cleaning and sterilising machinery.

“Vats in milk factories need to be cleaned every 6-8 hours to avoid the exponential growth of bacteria. This hinders usage and therefore affects output,” Romoli said.

“By saving hours per day in cleaning, it will yield an efficiency improvement stemming from fewer sterilisation cycles and less cleaning time within production as a whole.

“This will also reduce energy consumption as a result of fewer cleaning phases making food production quicker, safer and more profitable.”

Professor Romoli sees the long-term possibilities and implications for other sectors: “It is possible that any use of metal that needs to avoid the formation of bacteria will benefit from the TresClean product, such as medical cutting tools, sterile surfaces, dishwashers, or even saucepans”.

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