Olive oil coating on stainless steel vessels may halt bacterial growth

Toronto: Coating a thin layer of oils such as olive, corn or canola, at the surface of stainless steel cooking vessels can fill cracks and fissures as well as deter bacterial growth, new research suggests.

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 such as Salmonella, Listeria and E. coli.

However, coating a thin layer of cooking oil could be a simple and effective solution.

The solution minimises the risk of cross contamination, that could lead to foodborne 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.

"Contamination in food preparation equipment can impact individuals health and can cause costly product recalls," Hatton said, adding that the contamination can still occur after chemical-based cleaning.

The new method can also prevent bacteria from settling and essentially cleans the surface without leaving chemical residues on the stainless steel surface.