1. Restroom sinks
The filthiest area in a restroom (and therefore in the whole mall) isn't the toilet handle or the doorknob -- it's the sink, our experts say. Bacteria, including E. coli, fester on the faucet and handles because people touch those surfaces right after using the toilet, explains panelist Charles Gerba, Ph.D., a professor of environmental microbiology at the University of Arizona.
"The sink area is a moist environment, so bacteria can survive longer there," he adds.
2. Food court tables
Even if you see the table being wiped down, that doesn't mean it's clean, says panelist Elaine Larson, Ph.D., a professor of epidemiology at the Mailman School of Public Health at Columbia University: "The rags themselves can actually spread harmful bacteria such as E. coli if they are not changed and washed regularly."
3. Escalator handrails
"In our testing, we have found food, E. coli, urine, mucus, feces, and blood on escalator handrails," says Gerba. "And where there is mucus, you may also find cold and flu viruses." Tierno concurs: "We've found respiratory flora on handrails," he says, "which makes sense because people cough into their hands, then touch the rails."
4. ATM keypads
After testing 38 ATMs in downtown Taipei, Chinese researchers found that each key contained an average of 1,200 germs, including illness-inducing microbes like E. coli and cold and flu viruses, Tierno says. The worst key of all? The "enter" button, because everyone has to touch it, Gerba points out.
5. Toy stores
Toy stores can actually be germier than play areas, carousels, and other kid-friendly zones, Tierno says, simply because of the way little ones behave there. "Kids lick toys, roll them on their heads, and rub them on their faces, and all that leaves a plethora of germs on the toys," he says. The goods their parents don't buy end up back on the shelves, where your kid finds them.
6. Fitting rooms
You won't pick up much from the hooks or the chair. The germ culprit? What you try on.
"After people try on clothing, skin cells and perspiration can accumulate on the inside," says Tierno. "Both can serve as food for bacterial growth." You can even pick up antibiotic-resistant bacteria, such as MRSA (methicillin-resistant Staphylococcus aureus), just by trying on clothes, says Tierno.
7. Gadget shops
While you're playing around on that new smartphone, you could be picking up germs from the thousand people who tested it out before you. "Most stores do clean their equipment," says Tierno, "but they certainly don't clean after each use."
8. Makeup samples
Heading to the makeup counter? You might end up picking up a staph infection right along with the latest lipstick shade. A 2005 study found that between 67% and 100% of makeup-counter testers were contaminated with bacteria, including staph, strep, and E. coli. "This study shows us that someone was sick or went to the bathroom, didn't wash their hands, and then stuck their finger in the sample," Tierno says.