Bugs get the chop on wood

Chopping boards could hold the key to a better understanding of food poisoning, says a microbiologist at Leeds Metropolitan University.

Government figures released last week show that food poisoning is increasing and poor storage of food is often thought to be the cause. But cross contamination is one of the commonest causes of poisoning and can occur when the same chopping board is used for a variety of foods without adequate cleaning.

Craig Davidson, who is conducting the work, said: "You could be preparing a meal and start by chopping raw meat. Then you could cut up a salad on the same board immediately afterwards and the bacteria from the meat would pass on to the salad. As the salad is not cooked, the bugs will not be destroyed and eight to 12 hours later you have a group of sick people."

Even raw vegetables can contaminate other foods since they are often covered in earth which is full of bacteria. Mr Davidson says it is only by having a clearer understanding of how bacteria behave that people can be advised how to avoid cross contamination and which are the best surfaces to use.

Collecting bacteria for examination is not easy because the bugs stick stubbornly to surfaces. Mr Davidson intends to focus his research on stainless steel, a common work surface used in commercial kitchens. He is collaborating with scientists from the University of Wisconsin who are studying plastic and wooden chopping boards.

Already the research has revealed that wooden boards absorb bacteria so their surfaces are relatively bug free after a short time. But plastic boards tend to remain contaminated and are difficult to clean because of their rough surfaces. Glass chopping boards could be the best solution, says Mr Davidson, as they are non-porous.