Fridge salad drawers may contain on average more than 750 times the level of bacteria considered to be “clean”, according to new research.
Tests carried out for Microban Europe showed that the salad drawers of 30 home fridges had an average of 7,850 bacteria colony forming units per square centimetre. Some fridges from which swabs were taken had as many as 129,000 cfu/cm2.
This compares to standard recommendations for “clean” food preparation and storage surfaces from the US Public Health Service of no more than 10 cfu/cm2 and the European Community of 0-10 cfu/cm2.
Paul McDonnell of Microban Europe, which is based in Cannock, Staffordshire, said that potentially harmful bacteria that could be found in fridges could include S. aureus, E. coli, Salmonella and Listeria as well as other odour-causing microbes.
He explained: “The whole purpose of a fridge is to keep food safe and minimise the chances of bacteria and mould growth so it is worrying that in some there is clearly a substantial problem, as the research indicates.
“The performance of fridges is especially important in warmer weather, when high ambient temperatures mean that the potential for bacteria to multiply is high.
“The low temperatures of fridges will only inhibit the growth of bacteria in tandem with regular cleaning. When bacteria get a foothold and no cleaning is taking place, they will tend to multiply over a period of time.”
McDonnell added that, while it had not formed part of the formal research, Microban Europe believed from anecdotal feedback that attitudes to fridge cleanliness varied.
He said: “Some fridge owners regularly take all the food out of their fridge, wipe down the interior, and clean the salad drawers separately. However, some are effectively never cleaned, and that is probably where the problems occur.”
McDonnell explained that Microban Europe’s antibacterial protection was designed to be built by manufacturers into components such as the plastic parts used in fridges and was proven to kill the majority of bacteria that settled on a surface within 24 hours.
Appliance manufacturers using this technology include Whirlpool, who utilise a Microban air filter component built into several of their fridge ranges and is designed to minimise odours and the potential for bacteria.
He said: “We licence our antibacterial protection for use in all kinds of applications – from paint to towels and from tiles to vacuum cleaners. Our built-in technology helps to minimise the growth of odour-causing microbes and harmful bacteria.”
About the refrigerator research
This research was conducted for Microban Europe by taking samples from the salad drawers of 30 fridges, which were of a frost free design and were the primary refrigerator in each home. The samples were collected using a spongicide containing 10 ml of neutralising buffer and the estimated surface areas sampled was 100 cm2.
About Microban Europe’s antibacterial protection
On untreated products, bacteria can potentially double in number in 20 minutes but, by using a wide range of antibacterial technologies to suit each specific application, Microban disrupts their functioning, usually causing them to die within 24 hours.
A dedicated certification programme ensures that quality testing is regularly carried out on all products carrying the Microban branding and that antibacterial claims are technically supported.
This allows manufacturers utilising Microban to support robust statements about their efficacy – for example, “built-in to the product at the point of manufacture preventing 99.9% of bacteria and odour-causing bacteria, and providing longer lasting freshness.”