Our experts share their top tips for protecting your little one from bad bugs.

Most new moms and dads are paranoid about germs. And rightly so: Babies—especially newborns—have yet to build up their immunity to the viruses and bacteria that can cause illness. Still, it's impossible to shield your child from all the bugs out there—and you'd drive yourself nuts trying. "Parents should use common sense: Keep the house clean, keep their baby away from anyone who is obviously sick, and stay up-to-date on immunizations," says Philip M. Tierno Jr., Ph.D., director of clinical microbiology at New York University Medical Center and author of The Secret Life of Germs. Read on for more sanitary (and sanity-saving) rules every parent should know.

1. Don't let people put their paws on your baby.

"The biggest danger to babies is other people's hands," says Ken Haller, M.D., assistant professor of pediatrics at Saint Louis University School of Medicine, in Missouri. In fact, more than 80 percent of germs are transmitted by touch. Ask anyone who wants to hold your baby to first wash her hands with soap and warm water for 20 seconds. Because telling strangers to wash their hands isn't practical or polite, it may be easier to say, "I'm sorry, but my baby gets sick very easily, so I don't like too many people touching him."

2. Got a newborn? Nix trips to the shopping mall.

Experts agree that it's a good idea to limit where you take your baby during his first weeks. While a stroll in the park is fine, a trip to the mall is not. That's because newborns can easily pick up a bug when exposed to large numbers of people in a confined space. To be safe, keep her away from crowded places—especially those with lots of kids—for the first four to six weeks.

3. Never save unfinished bottles for later.

Whether you feed your baby breast milk or formula, throw out any leftovers as bacteria and digestive enzymes from a baby's saliva can backwash into the bottle and cause contamination. The same goes for baby food: Bacteria from a used spoon can taint what's in the jar. So if you're not going to use the whole thing, put just the portion you'll need in a bowl.

4. Place formula in the fridge.

To keep freshly prepared formula from spoiling, never leave it unrefrigerated for more than an hour. Just-pumped breast milk, however, can be kept at room temperature for up to ten hours, according to La Leche League International. Why the difference? Breast milk is loaded with antibodies and other substances that help keep bacteria at bay.

5. Wash your baby's clothes separately.

"Since family members' clothes—especially underwear—may contain contaminants that could wind up on your baby's sensitive skin, it's best to do her laundry separately," says Dr. Tierno. It's also smart to occasionally run an empty cycle of bleach and hot water to kill bacteria that may be lurking in the machine.

6. Be smart about sterilizing.

If pacifiers and bottles are brand-new, boil them before their first use. After that, wash them in the dishwasher or in warm, soapy water. Should you sterilize water for formula? "If your water comes from a municipal supply, unboiled tap water is fine—it's rigorously tested and monitored," says Roy Benaroch, M.D., assistant clinical professor of pediatrics at Emory University, in Atlanta. If your water comes from a well, have it tested for fecal contamination, nitrates, and heavy metals. Depending on the results, it may be best to boil it or even to use bottled water.

7. Take precautions when it comes to your pets.

Animals' mouths are full of germs that could cause illness. To keep your baby infection-free, don't let Fido lick her face or hands for the first two or three months; the same goes for cats. Once your baby is a bit older, her immune system will be stronger and there's less risk of her getting sick. But no matter your baby's age, always keep her away from the cat's litter box and wash her hands after she's been playing with a pet.

Originally published in Parents magazine.

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