How to clean your breast pump

Last week, the US Centers for Disease Control and Prevention (CDC) released updated guidelines on how to clean your breast pump, following a very sad case in Pennsylvania where a three-week-old preemie suffered meningitis and brain tissue damage from a bacterial infection contracted from expressed breast milk. A bacteria called Cronobacter sakazakii was later detected inside the mom’s breast pump parts and in the kitchen sink drain at home. 

Before you freak out, know that this particular kind of bacteria is super rare (the CDC says they usually see only four to six cases a year) and this is the first time they’re heard of a baby picking up this particular kind of infection from a contaminated breast pump or bottle of expressed milk.

It’s also good to know that human breast milk normally has a lot of bacteria in it—it’s supposed to! Healthy, full-term newborns pick up good bacteria from their moms’ breast milk and from skin-to-skin care all the time (it called “colonizing”), and it doesn’t usually cause infections. (However, donor breast milk from a milk bank is always pasteurized.)

And even though breast milk is a bodily fluid, formula is more prone to bacterial growth than expressed breast milk is. (Did you know that breast milk lasts three to six days when pumped and stored properly in the fridge, whereas powdered formula bottles are only good in the fridge for 24 hours after you first mix it?)

Cleaning your breast pump properly really depends on what brand and type of breast pump you have—make sure you read your manual and get to know which parts do what. Flanges, breast shields, membranes—it's confusing! Here are the highlights from the handy, illustrated CDC fact-sheet that all pumping moms and their partners should try to follow:

• Wash your hands before pumping.
• Use disinfectant wipes to clean the knobs and buttons of your pump before and after you use it, especially if it’s a shared or rented pump with multiple users.
• If you can, rinse the pump parts that come into contact with milk immediately and don’t leave milk residye in the flanges, shields or membranes.
• Don’t leave your pump parts to sit in the sink.
• Never soak or submerge breast pump parts in your kitchen sink. The CDC recommends using a dedicated plastic wash basin just for pump parts, nipples and bottles.
• It’s also safer to use a dedicated bottle brush or pump brush for cleaning. Don’t use the same sponge or scrubber you use for the rest of your dishes.
• Let pump parts air-dry arranged on a clean, freshly-laundered dishtowel or paper towel on the counter. Do not rub or pat dry with a dishtowel.
• Something beginners might not know: milk doesn’t travel through the tubing of your pump. The tubing is for the air flow that creates suction between the valves, membranes and your nipples. You shouldn’t see milk, moisture or mould in the clear tubing. (If you notice condensation in the tubing of an electric pump, try running the motor for a few minutes when it’s not hooked up to your breasts, to dry it out. If you see mould in the tubing, it’s a good idea to simply buy replacement tubing.)
• You’ll also want to sanitize everything—including your bottle brush—in addition to regular cleaning of pump parts. The CDC recommends sanitizing once a day. Put all pump parts and accessories in the dishwasher in one of those baskets designed for small, loose bottle parts (and use the sanitize and heat-dry settings). Other sanitizing options include submerging parts in boiling water for two minutes; using a steam sanitizer or sterilizer; or using those handy, microwaveable steamer sanitizing bags.
• You may want to sanitize more frequently for babies under three months, for preemies, and for infants with immune-compromising medical conditions. (Consult with your doctor.)

If you’re feeling confused (which is understandable—you’re also sleep-deprived!) about all the pumping, cleaning and milk storage rules, check out this chart. We’ve got all the specifics on how to store, sanitize, thaw and reheat bottles of breast milk or formula.

Read more: Bottle service: how to store, heat and clean bottles of breastmilk or formula How to use a breast pump How to combine breastfeeding and bottle-feeding