TUCSON, Ariz. — More news from the guy who warned about dangerous germs lurking in your kitchen sponges and dishrags and the muck in your office coffee cup: Your washing machine may not be as safe as you think either.
Environmental microbiologist Charles Gerba spends most of his time researching water quality. But he also enjoys hanging around in other people's homes, mostly in their bathrooms and kitchens--professionally, of course--searching for environmental hazards. And he finds them in abundance.
For instance, Gerba, a microbiology professor in the University of Arizona's soil, water and environmental sciences department, warned that bacteria such as E. coli and salmonella can be rampant in kitchen sinks, on counters and on cutting boards, often spread by sponges and dishrags contaminated by meat or poultry.
Or, as he puts it, "There are a hundred times more bacteria on a cutting board than a toilet seat, so lick a toilet seat rather than a cutting board."
Now he's found similar dangers in the home laundry.
"It hadn't been studied in the home very much," Gerba says. Most laundry studies for the presence of pathogens--disease-causing microorganisms--have been done in hospitals, he says.
His most recent study, of 50 homes in Tucson and 50 others in the Tampa Bay, Fla., area, has found that coliform bacteria, an indicator of unsanitary conditions, including the presence of diarrhea-causing E. coli, abound in many washing machines. Some linger even a load after you've washed your underwear, he says.
"They originate in feces, and we found that 60% of the washing machines had coliform bacteria. We just went in and swabbed your washing machine," Gerba said. "And about 10% had E. coli in it."
Next, Gerba and his researchers found that 40% of sterile cloths washed in non-bleach laundry contained fecal bacteria.
"We found that when you did clothes with underwear in it, it contaminated all the laundry. In fact, there was enough left over to contaminate the next wash load," he said.
Bacteria such as salmonella, which causes food poisoning, and viruses including hepatitis A and those that most commonly cause childhood diarrhea, rotavirus and adenovirus, also were targeted.
Although E. coli was killed in the permanent-press drying cycle, some salmonella survived on clothes that registered 131 degrees Fahrenheit. So did hepatitis A, adenovirus and some rotavirus.
Is Gerba painting too foul a picture?
