Titanium food surfaces could cut food poisoning
Food factory work surfaces coated in titanium could cut the number of food poisoning cases every year, according to research from scientists at Manchester Metropolitan University.
Following studies that looked at the way different surfaces harbour bacteria that could contaminate food, the researchers discovered that titanium could be better than stainless steel, as some pathogenic bacteria find it more difficult to attach themselves to the metal. The findings were presented at the Society for General Microbiology’s Autumn meeting held at Trinity College, Dublin last week.
“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 (E.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 were retained after cleaning surfaces with scratches. They found that the shape of the bacteria affected their retention: rod-shaped Listeria remained in tiny scratches less than half a micrometre across, and round Staphylococcus cells stuck in scratches measuring one micrometre across.
The results showed 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 Adele Packer. “Our findings also indicate that titanium coating may have a role in reducing the attachment of E. coli to food contact surfaces; E. coli cells attached to stainless steel much better than titanium.”
At the same meeting, delegates also heard from a scientist from Korea about research that showed how the use of brass plates on the bottom of fish tanks in restaurants could help to reduce the chances of customers suffering a particular type of food poisoning associated with eating raw fish and shellfish.
The study showed that copper ions diffuse out from a brass plate into a fish tank filled with seawater, and within 40 hours the copper killed 99.99% of the Vibrio food poisoning bacteria contaminating the living fish and shellfish.
The copper is absorbed by the bacteria, causing them to die and fall off the gills and skin of the fish. Vibrio are even flushed from the internal organs of the fresh fish, sinking to the bottom of the tank. The remaining copper ions are said to be absorbed from the seawater in the tank by sand and polyester filters, leaving safe, clean fish ready to be eaten by restaurant diners.
