NEWBORN

Bottle basics

What to know about s terilizing, using tap water and glass vs. plas tic .

A F T E R M Y husband and I brought our daughter home from the hospital, our entire condo kitchen quickly became devoted to cleaning, sterilizing and prepping her bottles. Just as we fi nished a feeding, it felt like it was time to start the whole process over again, and we still had so many questions. Should I buy glass bottles? One of the first things I wondered was whether I should be using glass bottles only. A recent study published in Nature Food measured levels of microplastics released by plastic baby bottles, and it’s a lot. However, experts still say you shouldn’t worry.

“Th ese days, parents don’t need to be concerned about the quality of the plastic that they’re using for baby bottles,” says Janice Heard, a Calgary paediatrician and member of the Canadian Paediatric Society public education and advisory committee. “It’s very well-regulated.” Bottles and liners available in Canada have been BPAfree since 2012. (Check for the numbers 1, 2, 4 or 5 on the bottom, inside the recycling symbol—they’re generally safe.)

John Boland, a professor of chemistry at Trinity College Dublin and one of the authors of the Nature Food study, agrees. “If you’re super concerned about it, you can use glass bottles. But know that there is no evidence of any adverse outcomes from exposure to these plastics.”

A few weeks in, when I realized just how many bottles we would need, plastic seemed much more aff ordable.

Michelle Th ompson, a mom in Toronto, also switched to plastic. “Glass bottles are heavy and I worried about dropping and cracking them,” she says.

Whether you’re using glass or plastic, you can sterilize the bottle parts by adding them to a pot of boiling water for at least fi ve minutes. A microwave or countertop sterilizer may be a safer bet if you have other kids running around the kitchen, says Marie Tarrant, a professor at the University of British Columbia School of Nursing. You can wash bottles by hand or in the dishwasher, but this method won’t off er proper sterilization—there are food particles on sponges and in every dishwasher, she adds. When can I stop sterilizing? Once your baby is around four months old, washing bottles thoroughly with soap and water is perfectly fi ne, says Tarrant. Four months is usually when infants start putting their fi ngers and toys in their mouth on their own too, adds Heard, so they’re already ingesting lots of germs and particles. Why can’t I mix formula with tap water? If you’re using powder or concentrated formula, it needs to be mixed with sterile water for the fi rst four months, says Tarrant. It’s the best way to ensure water is safe for new babies who are still developing their immune systems. Boil water for two minutes to sterilize it and get rid of things like chlorine and any salts that may be added to cit y water, explains Heard. If you’re on a well, boiling will reduce the hardness of the water and eliminate any bacteria coliforms that may not aff ect most adults but could be harmful to newborns, she says.

Th at said, if you’re away from your home or suddenly without electricity , don’t stress about not being able to boil water before mixing it with formula. “For most people living in cities, tap water is very safe,” says Heard. But because water quality differs in communities across Canada, the overall health recommendation covers all scenarios. Why can’t I warm up a bottle in the microwave? Babies don’t need warm bottles, but if you do want to heat it up, the safest way is to place it in a container or pot of warm water, or to use a bottle warmer. Never microwave a bottle—plastic or glass— says Heard. Liquid doesn’t heat up in a uniform way in the microwave, so the breastmilk or formula could be really hot in the middle. (Testing a drop on your wrist doesn’t eliminate the risk of scalding the baby’s mouth.) Plus, the microwave breaks down the healthy antibodies in breastmilk.

In hindsight, I wish we had invested in a bottle warmer. We usually mixed two bottles ahead of time and stored them in the fridge, then warmed them in a container of hot water when it was time for a feeding. Th is took about 15 minutes—an eternity when your baby is cr ying. How long will a prepared bottle last out of the fridge? Generally, a prepared but untouched bottle left at room temperature for two to three hours is safe to give to your baby, says Heard. Any longer and it should be disposed of, regardless of whether it was touched or not.

If your little one doesn’t fi nish the whole bottle, you should also toss it, whether it’s breastmilk or formula. “Babies have enzymes in their saliva that will start to break the milk down and contaminate it,” says Heard.

When leaving the house with her daughter, Th ompson says she would pack two bottles of sterile water and a separate container of pre-measured formula in her diaper bag. “It wasn’t so bad to carry,” she says. “If anything, bottle-feeding gave me more freedom to have help from others, which was key for