Oil coating on steel vessels may halt bacterial growth

Many foods produced on an industrial scale include raw ingredients mixed together in enormous stainless steel machines that can be difficult to clean. With repeated use, equipment surfaces get minute scratches and grooves, providing bacteria and biofilms the perfect place to hide.

While the surface scratches may appear small to the naked eye, they are like a canyon to bacteria, which are only a few micrometers in size. Surface-trapped food residue and bacteria then increase the risk of contamination from microorganisms.

However, coating a thin layer of cooking oil could be a simple and effective solution. This could minimises the risk of cross contamination, that could lead to food-borne disease and results in a 1000 times reduction in bacterial levels inside the industrial machines tested, the findings showed.

“Coating a stainless steel surface with an everyday cooking oil has proven remarkably effective in repelling bacteria,” said Ben Hatton, Professor at the University of Toronto in Ontario, Canada. “The oil fills in the cracks, creates a hydrophobic layer and acts as a barrier to contamination on the surface,” he added.

The research, published in the journal ACS Applied Materials and Interfaces, showed that cooking oils such as olive, corn or canola could provide a safer option for cleaning food-processing equipment than the harsh chemicals and disinfectants that are typically used.