New York Times News Service - November 2, 2000

    Scientists at the University of Wisconsin have discovered that wooden cutting boards kill food-poisoning bacteria, while the bacteria survive nicely on plastic cutting boards.
    Dean 0. Cliver and Nese 0. Ak, microbiologists at the university's Food Research Institute, stumbled on the finding while seeking ways to make wooden boards as safe as plastic. The plastic boards have been widely promoted for years as safer than wood.
    To their surprise, they found that when boards were purposely contaminated with organisms like salmonella, listeria and escherichia coli -- common causes of food poisoning - 99.9 percent of the bacteria died off in three minutes on the wooden boards, while none died on the plastic ones.
    When contaminated boards were left unwashed overnight at room temperature bacterial counts increased on the plastic, but none of the organisms could be found on the wooden boards the next morning.
    It had long been believed that bacteria from raw foods like chicken would soak into a wooden board and be difficult to remove, even when washed; then when other foods, like salad ingredients that are eaten raw, are cut on the same board, the dangerous bacteria, could be transferred to the consumer.
    Plastic was assumed to be safer because it is nonporous and contaminating organisms could be readily washed off.
    The researchers tested boards made from seven different species of trees and four types of plastic and found similar results: wood was safer than plastic, regardless of the materials used. Thus far, however, the researchers have been unable to learn what in wood makes it so inhospitable to bacteria.
    Based on the new studies, Cliver said, "Wood may be preferable in that small lapses in sanitary practices are not as dangerous on wood as on plastic." But he cautioned against being "sloppy about safety" and warned cooks to wash off cutting surfaces after cutting meat, chicken or fish, whether the board is wood or plastic.