News releases

FOR IMMEDIATE RELEASE
January 21, 1993

CONTACT: Dean Cliver, (608) 263-6937

STUDY: WOOD CUTTING BOARDS, NOT PLASTIC, ARE SAFER FOR FOOD PREP

        MADISON Q For decades now, cooks in homes and restaurants 
have been urged to use plastic rather than wood cutting boards in 
the name of food safety. The fear is that disease-causing bacteria 
Q salmonella from raw chicken, for example Q will soak into a 
cutting board and later contaminate other foods cut on the same 
surface and served uncooked, such as salad ingredients. 
        It's become an article of faith among "experts" that plastic 
cutting boards are safer than wood for food preparation because, 
as the thinking goes, plastic is less hospitable to bacteria.
        It seems reasonable, but it just ain't so, according to two 
scientists at the University of Wisconsin-Madison's Food Research 
Institute. 
        Dean O. Cliver and Nese O. Ak, food microbiologists in the 
College of Agricultural and Life Sciences, have found that in some 
as yet unknown way wooden cutting boards kill bacteria that 
survive well on plastic boards. 
        "This flies in the face of the prevailing wisdom," says 
Cliver. "It isn't what I expected. Our original objectives were to 
learn about bacterial contamination of wood cutting boards and to 
find a way to decontaminate the wood so it would be almost as safe 
as plastic. That's not what happened." 
        Cliver is quick to point out that cooks should continue to be 
careful when they handle foods and wash off cutting surfaces after 
they cut meat or chicken that may be contaminated with bacteria.
        "Wood may be preferable in that small lapses in sanitary 
practices are not as dangerous on wood as on plastic," he says. 
"This doesn't mean you can be sloppy about safety. It means you 
can use a wood cutting board if that is the kind you prefer. It 
certainly isn't less safe than plastic and appears to be more 
safe."
        Cliver and Ak began by purposely contaminating wood and 
plastic boards with bacteria and then trying to recover those 
bacteria alive from the boards. They also tested boards made from 
seven different species of trees and four types if plastic. They 
incubated contaminated boards overnight at refrigerator and room 
temperatures and at high and typical humidity levels. They tested 
several bacteria Q Salmonella, Listeria and enterohemorrhagic 
Escherichia coli Q known to produce food poisoning. The results 
consistently favored the wooden boards, often by a large margin 
over plastic boards, according to Cliver.
        The scientists found that three minutes after contaminating a 
board that 99.9 percent of the bacteria on wooden boards had died, 
while none of the bacteria died on plastic. Bacterial numbers 
actually increased on plastic cutting boards held overnight at 
room temperature, but the scientists could not recover any 
bacteria from wooden boards treated the same way.
        So where did we get the idea that wood isn't safe? Cliver and 
Ak don't know. They did a literature search and have not found any 
studies that evaluated the food safety attributes of wood and 
plastic cutting boards.
        Although Ak, a graduate student at the Food Research 
Institute, will soon return to Turkey, Cliver hopes to continue 
the studies. A major question now, he says, is why wood is so 
inhospitable to bacteria. He and Ak have tried unsuccessfully to 
recover a compound in wood that inhibits bacteria.
        The first year of the study was funded by the Food Research 
Institute with unrestricted food industry gift funds; other 
funding sources are now being sought. Cliver and Ak will soon 
submit an article based on the research to a refereed scientific 
journal.

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