Now that many careful cooks have replaced their wooden cutting boards with plastic ones to try to avoid spreading bacteria, two researchers say wood is better after all.
The prevailing wisdom was that bacteria, such as salmonella found in raw chicken, could soak into a wooden board and later contaminate other foods cut on the board and cause illness.
Authorities were especially worried that bacteria would be transferred to foods eaten raw, such as salad ingredients. Heat kills many bacteria in cooking.
It was presumed the bacteria would find a nonporous surface like plastic a less hospitable place to live, reducing the danger of contamination.
Two scientists at the Food Research Institute of the University of Wisconsin in Madison set out to learn how the bacteria lived in wooden cutting boards and then how to decontaminate the wood and make it as safe as plastic.
What they found, however, was that the wood was safer to begin with.
Microbiologists Dean O. Cliver and Nese O. Ak contaminated wooden and plastic boards with several bacteria that cause food poisoning--salmonella, listeria and E. coli . They tested boards made of four species of trees and four types of plastic. They also held contaminated boards overnight in a refrigerator, at room temperature, and in high humidity.
The tests consistently favored the wooden boards, Cliver said.
"It surprised us too," he said.
Three minutes after contamination, 99.9% of the bacteria on wood had died, while none of the bacteria on plastic had died. And bacteria increased on plastic boards kept overnight at room temperature, while no bacteria could be found the next morning on wood left at room temperature, the researchers said.
They have not been able to determine why the wood apparently is safer.
"We want to know what happens to those bacteria. We have not recovered any bodies from down there yet," Cliver said.
"The second thing that I think is real important is, 'What is going on with the plastic?' " he said. "What can be done to plastic that will make it safer?"
The findings should not result in any less diligence in the kitchen, however. Cooks still should wash cutting boards, hands, knives and any other item that touches raw meat or fish with hot, soapy water immediately after use.
Cliver and Ak said they could find no previous studies comparing cutting surfaces for contamination and believe the advice to use plastic was based on common sense.
If other research confirms their findings, cooks should be happy: Wood is gentler on knives, beloved equipment to many people who spend a lot of time in the kitchen.