Don't toss those wood cutting boards just yet


February 03, 1993|By ROB KASPER

Spare that wood cutting board, it might not spoil the salad. That is what the research of a food biologist at the Food Research Institute of the University of Wisconsin at Madison indicates.

Professor Dean O. Cliver had heard the warnings about wood cutting boards. Namely that a disease-causing bacterium, like salmonella from raw chicken, will soak into a wood cutting board and later contaminate the lettuce cut up on the same surface. On the other hand, plastic cutting boards, with their harder surfaces, were supposed to be safer than those made of wood.

But when Cliver and a fellow researcher began testing wood and plastic cutting boards for bacteria, they found just the opposite.

After a year of working with several bacteria known to produce food poisoning, they found that the bacteria thrived on the plastic cutting board but virtually disappeared from the surface of the wood boards.

Cliver said that he and fellow researcher, Nese O. Ak, found that three minutes after they contaminated new and hacked-up wood and plastic boards with bacteria, 99 per cent of the bacteria on the surface of the wood boards had died. None of the bacteria died on the plastic boards.

Moreover, when the bacteria on plastic boards were held overnight at room temperature, their numbers increased. Meanwhile, no bacteria were found on the wood boards given the same overnight treatment.

What this means, Cliver said in a telephone interview the other day from his office in Madison, is that "small lapses in kitchen sanitation are less of a problem with a wood cutting board than with a plastic one."

Cliver said that as a result of the study, he feels comfortable using his wooden cutting board to cut up a raw chicken and then to chop lettuce for a salad, as long as the board is washed with detergent and water between the tasks.

If he were using a plastic cutting board, especially one gouged with knife marks, he said he would feel comfortable only if, between the tasks, the board was washed in an automatic dishwasher. Bacteria can hide in the gouges of a plastic cutting board, he said.

Calls to various United States Department of Agriculture offices in Washington yesterday found few officials familiar with or willing to comment on Cliver's cutting board work.

When told of the outlines of the findings, one USDA home economist said that the researchers may be onto something, but cautioned that it was only one study.

One study is apparently not enough to change policy. Callers to the USDA Meat and Poultry Hot Line are still warned against using wood cutting boards. The wood boards "look pretty but are difficult to clean thoroughly."

Plastic and acrylic boards, the USDA recording said, are safer because they are "easy to clean."

Cliver said he and Ak are in the process of submitting their work to refereed scientific journals for publication.

Cliver and Ak began the experiment with the idea of finding a way to decontaminate wood so it would be almost as safe as plastic. The direction of the study changed when they found that the bacteria flourished on the plastic surfaces but virtually disappeared from the wood surfaces.

Cliver said that some results of the cutting board work still remain unclear to him.

For instance, he did not know why the wood surface was so inhospitable to bacteria. And he and Ak had not been able to isolate the compound in wood that battles the bacteria. While the bacteria are not on the surface of the wood, they could be down deeper in the wood out of harm's way, he said.

On the other side of the issue, Cliver, 58 years old and a veteran researcher, said he has yet to find the scientific basis for the idea that wood cutting boards are not safe.

Cliver's study was funded by unrestricted gifts from food industry sources.

I wished Cliver well in this research, for two reasons.

On a broad level, it is refreshing to see conventional wisdom challenged.

And on personal level, it meant that I was justified in hanging on to my favorite cutting board.

It is ancient. It is heavy. It is a pain to clean.

But that wood cutting board is an old friend. It knows its away around the kitchen, and apparently it knows how to handle bacteria.

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