Two weeks ago, the Environmental Protection Agency ordered Joyce Chen Inc. of Billerica, Mass., to stop selling its popular line of what it calls anti-bacterial cutting boards. The regulatory agency charged that the pesticide impregnated in the surfaces of these boards -- five of which are marketed under the companyís name, another seven under a "Board of Health" brand label -- had not been proven effective against the organisms that cause food poisoning.
Because germs that cause food poisoning can hide out in the knife-scarred nooks and crannies that develop on the surface of a plastic cutting board with use, many manufacturers have been investigating ways to impregnate that plastic with germ-fighting agents.
"We will not allow the publicís health to be jeopardized by potentially false claims," said Steve Herman, EPAís assistant administrator for enforcement and compliance, in a June 27 announcement. "Before a company can legally claim a product protects people from disease-causing germs, it must first prove it is safe and effective for consumer use."
Herman noted that any consumer products that claim to prevent, destroy, or repel pests must be registered with EPA under the Federal Insecticide, Fungicide, and Rodenticide Act, better known as FIFRA. Because the packaging and advertising materials for the Joyce Chen cutting boards "implied and/or stated that the products could kill or mitigate pests," these boards constitute unregistered pesticides, explains EPA enforcement officer Brenda Mosley.
Points out Joyce Chen spokesman John Geldert, the company never claimed that the products were pesticidal -- able to kill microbes, only that they were bacteriostatic -- able to prevent the growth of germs. He says that it appears EPA was concerned that users might misinterpret the productsí packaging claims to mean that the surfaces killed bacteria and therefore didnít have to be washed. However, he notes, even with this special surface, "consumers still have to take care of the board and keep it sanitary."
Those were indeed some of EPAís concerns, Mosley told Science News Online. However, she adds, the problem goes beyond that. Under FIFRA, no product can make claims that suggest any potential health or safety benefits from a bacteria-fighting agent unless that agent has been registered with EPA for that use and the manufacturer has provided data to validate those claims.
Not only is the substance, called Bacteron, that has been impregnated into the Joyce Chen plastics not a registered pesticide, Mosley says, but Joyce Chen Inc. has also provided no data to show that its treated boards perform as claimed.
Mosley says that the cutting boards should present no danger as long as they are thoroughly cleansed in soap and hot water after each use. However, EPA would like to know what Bacteron consists of. Currently, Mosley says, the agency has been informed of only one of the productís active ingredients: zinc oxide.
This compound is generally recognized as safe for human consumption. Moreover, it has been approved for use in controlling the growth of odor-causing bacteria. The agency, however, has no data indicating that zinc oxide also controls the growth of Salmonella, E. coli, and other food-poisoning microbes, despite claims on the cutting boardsí labels that it does.
EPAís order that Joyce Chen Inc. "cease and desist" its sale of these cutting boards is just the latest in a string of related actions. On May 28, EPAís Chicago-area enforcement division reached a settlement with Ecko Housewares Inc. of Franklin Park, Ill. The company agreed to pay a $100,000 fine and cease antibacterial claims for a wide range of products -- including brushes, sponges, and cutting boards -- whose plastic contained a "Germ Away" formulation, Mosley says.
Like the Joyce Chen products, Ecko had made unsubstantiated pesticidal health claims for these housewares, she notes.
So did the 3M Corp. in its advertising for O-cello sponges, which also contain an allegedly antibacterial agent embedded directly into the product. On March 7, EPA ordered the company to cease the sale of these products. Eleven days later, the regulatory agency amended its order, saying the company could continue selling the sponges if it covered over or removed any antibacterial health claims on the product labels and advertising. However, notes Jerry Stubbs, a branch chief with EPAís Toxics and Pesticides Enforcement Division, the 3M case remains "an open investigation."
This issue of improper antibacterial health claims also triggered EPAís moves against the Pawtucket, R.I.-based Hasbro Inc., maker of Playskool toys. On April 22, the agency entered a settlement with the company. In addition to paying a $120,000 fine, Hasbro must cease to make any health claims about its nine toys whose plastic surfaces had been embedded with Microban, a bacteriostatic compound.
Like zinc oxide, Microban has been legally used in other products to prevent the growth of certain bacteria, Mosley notes. However, she points out, in each of those products, the antibacterial agents were used to protect the product -- not the health of the productís user.
Itís a critical distinction, she notes, because pesticides can win an exemption from FIFRA if they are present only to protect a product -- such as to keep down the growth of mildew in the plastic used in lawn chairs or to prevent the buildup of odor-causing bacteria in clothes.
The EPA regulators' recent activity is a response to escalating consumer fears about the home as a reservoir of infectious germs. The General Accounting Office estimates that as many as 81 million cases of foodborne illness occur in the United States each year, racking up health care costs in excess of $5 billion.
Though few studies have attempted to tally how many of these cases trace to food prepared at home (versus restaurants), microbiologist Elizabeth Scott of Newton, Mass., has made several stabs at estimating the share attributable to home-cooked food in her native Britain and several European countries, where much more detailed national records on cases of food poisoning are available. Those analyses conclude that the vast majority of these gut-wrenching infections stemmed from contamination in the home.
The EPA actions are sure to rekindle a long-simmering debate among home economists on the relative safety of wood versus plastic for cutting boards and other surfaces that come into contact with food. While many cooks prefer the look and feel of hardwood, the Food and Drug Administration has long recommended using only plastic (SN: 2/6/93, p. 84), arguing that while germs can be washed off plastic, woodís micropores offer ideal hiding places for bacteria to evade eviction during a soap-and-water cleansing.
Yet when Charles E. Benson, a microbiologist at the University of Pennsylvania School of Veterinary Medicine in Kennett Square began probing the basis of such recommendations, he was surprised to find that "little of it was based on research." Instead, he found, these prescriptions usually constituted "suggestions based on no concrete evidence that something really works."
Itís a problem that used to frustrate Ban Mishu Allos when he worked in the foodborne pathogens section at the Centers for Disease Control and Prevention in Atlanta.
"People would call CDC asking us if it was better to use a wooden or plastic cutting board," she recalls. "And the answer that weíd always give was that there are no data." When pressed, she would say, "if youíre more comfortable using a plastic board, because it seems logical that it ought to be more sterile, fine. But thereís no hard data proving thatís the case."
Scott notes that what people term "common sense is really more tradition. A lot of it doesnít seem to be supported by anything."
For instance, she notes, "so-called experts from this university or that one are always saying wash your dish cloth and sponge in soap and hot water. Or wash your countertop and cutting board with soap and water. But that isnít really enough," her data show, "because this doesnít kill the bacteria. In fact, it often causes you to spread the contamination."
In one study that she performed while still in England, she applied a detergent and water to a counter top and then scrubbed. "Afterwards," she found, "there were more bacteria than when you started." The reason: Most damp sponges, sitting near the sink, contain millions of bacteria. By adding the detergent, she found, you break up the bacterial colonies and spread them around."
When Dean O. Cliver of the University of California-Davis began testing that common-sense wisdom as it pertains to cutting boards, 4 years ago, he too found that it didnít seem to hold up. Microbiologically, at least, wood outperformed plastic, because he could extract plenty of live bacteria from the surfaces of plastic boards but virtually none from wood boards that had initially been tainted with the same number of bugs (SN: 2/6/93, p. 84).
In follow-up tests, heís witnessed the same trend. Even after slathering bacteria onto wood cutting boards, he finds it next to impossible to retrieve them because they are quickly drawn beneath the surface into the initial 1 millimeter of wood (see Sponges and sinks and rags, oh my!).
Though many bacteria die during this process, some can remain alive for hours. However, even they canít contaminate food unless the boards are cut open, heís found. "And from that standpoint," he told Science News Online, "our results are reassuring."
Yet even he wouldnít trust his wood cutting boards to fully decontaminate themselves. He washes them thoroughly -- and, when in doubt, microwaves them for a deep steam cleaning. His team published its experimental findings on how procedures for using a microwave to clean hardwood boards last year in the Journal of Food Protection, and equivalent data for dishrags or sponges, this year, in a journal serving the commercial food-service industry.
The studies by Cliverís team at the University of California-Davis indicate that plastic boards retain large quantities of disease-causing germs at the surface -- and that those bugs tenaciously resist removal by hand washing. While you canít microwave plastic surfaces clean (they donít heat up enough to roast the bugs), a hot dishwasher cycle dislodges or kills microbial squatters, he and others have shown.
Donít forget stainless steel surfaces -- kitchen pans, knives, sink, food- processor blades, and mixing bowls. "A couple of studies that I did with some high school students showed that what looks clean is not necessarily clean," notes Benson. These metal kitchen wares emerged from a standard hand washing bearing residues of food and bacteria. These science-fair studies, which werenít quantitative and didnít culture specific strains of bacteria, met the studentsí needs. "But weíd like to take it further now and give it some good documentation," Benson says.
Even hand-washed stainless steel can harbor germs, as seen here. Pseudomonas bacteria (dyed pink) has attached via thin filaments to take up residence amid a field of microscopic food particles (dyed yellow).
Credit: E.A. Zottola, Univ. of Minn.
Though most of the utensils they surveyed did emerge "relatively clean" from a dish washing machine, Benson worries about the water that often sits on the bottom of the dishwasher between washings. "Iíd hate to think of it as a growth medium for these bugs," he says. Itís another issue heíd like to investigate.
To be safe, Edmund A. Zottola of the University of Minnesota recommends washing metal with soap, to break up those bacterial colonies, then rubbing the utensils vigorously. He follows this up with a sanitizing rinse of dilute bleach.
That may be suitable for commercial kitchens, but Susan Sumner, a food scientist at Virginia Polytechnic Institute and State University, has developed a less toxic alternative for home use that may also prove more versatile. She sprays contaminated surfaces with a mist of vinegar and then a mist of hydrogen peroxide. The disinfectant combo kills bacteria on not only metal, plastic, and wood, but also on foods, such as meat and lettuce leaves (see How to disinfect your salad).
Park, P.K., and D.O. Cliver. 1996. Disinfection of household cutting boards with a microwave oven. Journal of Food Protection 59(October):1049.
Park, P.K., and D.O. Cliver. 1997. Disinfection of kitchen sponges and dishcloths by microwave oven. Dairy, Food, and Environmental Sanitation 17(March):146.
Fox, N. 1997. Spoiled: The dangerous truth about a food chain gone haywire. New York: Basic Books.
Knabel, S.J., et al. 1995. Foodborne illness: Role of home food handling practices. Food Technology 49(April):119.
Peters, D., S.S. Sumner, et al. 1996. Control of pathogenic bacteria on fresh produce, a paper (abstract #168) presented in Seattle on July 2, at the 83rd annual meeting of International Association of Milk, Food and Environmental Sanitarians.
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_____. 1996. Lessons from a case of toxic ice cream. Science News Online (July 27).
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Ban Mishu Allos
A3310 Medical Center North
Division of Infectious Diseases
Vanderbilt University School of Medicine
Nashville, TN 37232
Charles E. Benson
Department of Microbiology
University of Pennsylvania School of Veterinary Medicine
New Bolton Center
Kennett Square, PA 19348-1692
Dean O. Cliver
Department of Population Health and Reproduction
School of Veterinary Medicine
University of California, Davis
Davis, CA 95616-8743
Joyce Chen Inc.
6 Fortune Drive
Billerica, MA 01821
Brenda Mosley and Jerry Stubbs
Toxics and Pesticides Enforcement Division
US Environmental Protection Agency
401 M Street, SW
Washington, DC 20460
Toxics and Pesticides Enforcement Division
US Environmental Protection Agency
401 M Street, SW
Washington, DC 20460
Department of Food Science and Technology
College of Agriculture and Life Sciences
Virginia Polytechnic Institute and State University
Blacksburg, VA 24061-0418
Edmund A. Zottola
Department of Food Science and Nutrition
University of Minnesota
1334 Eckles Avenue
St. Paul, MN 55108
This week's Food for Thought has been prepared by Janet Raloff, senior editor of Science News.