In the food industry surfaces must be easy to clean. Wear of food contact surfaces through abrasion, cleaning and impact damage increases the surface roughness. Researchers have looked at the way different work surfaces harbour bacteria that could contaminate food. They discovered that titanium could be a better work surface than stainless steel, as some pathogenic bacteria find it more difficult to attach themselves to the metal.
"It is important that surfaces in a hygienic environment are kept clean," said Adele Packer from Manchester Metropolitan University. "Scratches may entrap micro-organisms such as Escherichia coli and protect them from being removed during cleaning. We measured scratches found on different surfaces and reproduced them in our lab. We coated the surfaces with titanium so that they all had the same chemistry and the only difference was the surface roughness."
The researchers looked at how bacteria are retained after cleaning to surfaces with scratches. They found that the shape of the bacteria affected their retention; rod-shaped Listeria remained in tiny scratches less than 0.5 micrometers across, and round Staphylococcus cells stuck in scratches measuring one micrometer across.
"The results show that surface scratches retain bacteria well if they are of comparable size. The more tightly the bacteria fit in the scratches, the more difficult they are to remove during cleaning," said Packer. "Our findings also indicate that titanium coating may have a role in reducing the attachment of Escherichia coli to food contact surfaces; Escherichia coli cells attached to stainless steel much better than titanium."
"These results will help designers make hygienic surfaces that are easy to clean. This should help to reduce the chances of cross-contamination and cross infection," said Packer.
MEDICA.de; Source: Society for General Microbiology