Breast pump parts should be sanitized at least once daily if your baby is under 2 months old, was born prematurely, or has a weakened immune system. For older, healthy babies, daily sanitizing isn’t strictly necessary as long as you’re thoroughly cleaning every part after each use. That distinction between cleaning and sanitizing is important, because they’re two different steps with different purposes.
Cleaning vs. Sanitizing
Cleaning means washing pump parts with liquid dish soap and warm water after every single pumping session. This removes milk residue and most bacteria. Every part that touches breast milk, including bottles, valves, flanges (breast shields), and membranes, needs this wash each time you pump.
Sanitizing is an extra step that kills more germs than washing alone. It doesn’t make parts fully sterile (that’s not achievable at home, even with boiling), but it reduces bacteria to a level that’s safe for your baby. Think of cleaning as the non-negotiable baseline and sanitizing as the additional layer of protection.
When Daily Sanitizing Matters Most
The CDC recommends sanitizing at least once a day if your baby falls into any of these categories:
- Under 2 months old: Their immune system is still very immature, making them more vulnerable to infections from bacteria that survive a regular wash.
- Born prematurely: Preterm babies carry a higher risk of infection regardless of their current age.
- Immunocompromised: Babies undergoing medical treatment like chemotherapy, or those with conditions that weaken their immune defenses, need the extra protection.
If your baby is healthy and older than 2 months, you can skip the daily sanitizing step, provided you’re genuinely thorough with cleaning after each use. “Thorough” means disassembling every part, scrubbing with soap rather than just rinsing, and making sure no milk film remains in small crevices like valve membranes.
How to Sanitize at Home
You have a few options, and all of them work well enough for single-user pump parts. The simplest method is boiling: place the disassembled parts in a pot of water and keep it at a rolling boil for five minutes. Use tongs to remove them and set them on a clean surface to air dry.
Microwave steam bags or standalone microwave sterilizers are another popular choice. These don’t meet the technical FDA definition of sterilization, but the FDA confirms they adequately reprocess parts for safe home use. They typically take two to five minutes depending on the product, and most bags can be reused around 20 times before replacement.
If your dishwasher has a sanitize cycle (sometimes labeled “hot” or “sanitize”), you can place pump parts on the top rack. The high-temperature rinse at the end provides the sanitizing step. Check your pump manufacturer’s instructions first, since not all parts are dishwasher-safe, especially thin silicone membranes that can warp.
The Right Order: Wash First, Then Sanitize
Sanitizing only works properly on parts that are already clean. Dried milk residue can shield bacteria from heat, so always wash with soap and water before you sanitize. A good routine looks like this: pump, disassemble, wash all parts in warm soapy water (a dedicated wash basin is ideal rather than the kitchen sink), rinse, then sanitize once at the end of the day.
Between pumping sessions during the day, you just need the wash step. Save the sanitize step for one session, typically the last pump of the evening so parts are ready for overnight or the next morning.
Drying and Storage After Sanitizing
Air drying is the recommended approach. Place parts on a clean dish towel or a drying rack that you use only for pump equipment. Avoid using a regular kitchen towel to rub parts dry, since towels can carry bacteria and recontaminate what you just sanitized.
Once parts are fully dry, store them in a clean, protected container with a lid. Reassembling parts while they’re still damp creates a warm, moist environment that encourages bacterial growth, so patience here matters. If you’re pumping again within a short window and parts haven’t fully dried, that’s generally fine for a healthy older baby, but for newborns and vulnerable infants, try to allow complete drying.
The Refrigerator Shortcut
You may have heard about placing unwashed pump parts in the refrigerator between sessions to save time. The idea is that cold temperatures slow bacterial growth enough to make a mid-day wash unnecessary. The CDC does not endorse this practice. Cold slows bacteria but doesn’t stop them entirely, and milk residue left on parts for hours provides a food source for any organisms present. If you choose to do this for convenience, understand that it carries more risk than washing after every session, and it’s not appropriate for babies who are very young, premature, or immunocompromised.
Tubing, Backflow Protectors, and Replacement
Tubing that stays dry during pumping (common with closed-system pumps) doesn’t need routine washing or sanitizing. If you see moisture or milk droplets inside the tubing, run the pump for a few minutes with the tubing attached but disconnected from the collection kit. This pulls air through and dries the inside. If condensation keeps appearing or you spot mold, discoloration, or a milky film inside the tubing, replace it. Mold inside tubing can’t be reliably cleaned.
Backflow protectors and diaphragms should be disassembled and cleaned along with the rest of your kit. These small parts are easy to overlook, but milk can reach them, especially if a bottle overfills or the pump is tilted during use.
Silicone membranes, valves, and duckbill valves wear out with use. When they lose their shape, feel sticky, or don’t create proper suction anymore, replace them. Most manufacturers suggest swapping these every one to three months depending on how frequently you pump. Worn parts don’t just affect suction and milk output; tiny cracks can harbor bacteria that washing won’t reach.
Before You Handle Clean Parts
Washing your hands with soap and water for at least 20 seconds before touching sanitized parts or assembling your pump prevents recontamination. This step is easy to skip when you’re exhausted and pumping at 3 a.m., but it’s one of the simplest ways to keep your milk safe. The same goes for wiping down the surface where you pump and assemble your kit, especially countertops or desks that see a lot of daily traffic.