Yes, washing baby bottles in the dishwasher is safe, and the CDC considers it an effective cleaning method for infant feeding items. If your dishwasher has a hot water cycle and a heated drying setting (sometimes labeled “sanitize”), you can skip a separate sanitizing step entirely. Here’s what to know to get the most out of each cycle.
How to Load Bottles in the Dishwasher
Before loading anything, take every bottle completely apart. That means separating the bottle body, nipple, cap, ring, and any internal valves or venting pieces. Give each part a quick rinse under running water (warm or cold is fine) to knock off leftover milk or formula. Dried milk residue can stick even through a full wash cycle, so this step matters.
Place larger pieces like bottles and caps on the top rack. Small parts like nipples, rings, and valves should go inside a closed-top dishwasher basket or a mesh laundry bag. Without containment, these lightweight pieces can fall through the rack, land near the heating element, or get trapped in the dishwasher filter where they won’t get cleaned properly.
The Settings That Matter
Run your dishwasher on a hot water cycle with the heated drying option turned on. Many newer dishwashers have a dedicated sanitize setting that raises the final rinse temperature high enough to kill most bacteria. When you use either heated drying or a sanitize cycle, the CDC says no additional sanitizing (boiling, steaming, or chemical sanitizing) is needed. A standard cycle without heated drying still cleans bottles, but you may want to add a separate sanitizing step for extra peace of mind, especially for younger babies or those with health concerns.
Before you unload clean bottles, wash your hands with soap and water. It sounds minor, but touching freshly sanitized items with unwashed hands reintroduces the very germs you just removed.
Is Dishwasher Detergent Residue a Concern?
You may have seen headlines about a 2023 study suggesting dishwasher detergent and rinse aid could damage gut cells. That study had significant limitations. Researchers at Michigan State University’s Center for Research on Ingredient Safety reviewed it and found the detergent concentrations used in the experiments were more than 300 times stronger than what dishes are actually exposed to in a home dishwasher. Even the study’s most diluted test was still twice as concentrated as a normal wash. The researchers also used colorectal cancer cells rather than healthy intestinal tissue, making the results a poor stand-in for what happens in a real human gut.
The bottom line: when used as directed, dishwasher detergents and rinse aids are safe for cleaning items your baby eats and drinks from.
What Repeated Washing Does to Nipples
Silicone nipples hold up well in the dishwasher, but they don’t last forever. Research from the University of Massachusetts Amherst found that repeated exposure to moist heat (specifically steam sterilization) breaks down silicone rubber over time, releasing tiny microplastic and nanoplastic particles. The study estimated that through steam disinfection alone, a baby could ingest over 660,000 micro-sized plastic particles by age one.
That research focused on steam sterilization rather than standard dishwasher cycles, so the numbers don’t translate directly. Still, it’s a useful reminder to inspect nipples regularly. If silicone looks cloudy, sticky, cracked, or thin, replace it. Most manufacturers recommend swapping nipples every two to three months regardless of how they look. Latex nipples degrade faster than silicone and are more sensitive to heat, so check those even more frequently.
When Cleaning Alone Isn’t Enough
For healthy, full-term babies, thorough cleaning in a dishwasher with a heated drying cycle is considered sufficient. Babies under three months, premature infants, and those with weakened immune systems benefit from an extra sanitizing step. If your dishwasher lacks a heated drying or sanitize cycle, you can sanitize separately by placing disassembled parts in a pot of boiling water for five minutes or using a microwave steam sterilizer bag.
The first use of any new bottle also calls for sanitizing before the initial wash, regardless of your baby’s age or health status.
Dishwasher vs. Hand Washing
Both methods are effective when done correctly. The dishwasher’s advantage is consistency: it hits higher temperatures than most people use at the sink, and the heated drying cycle adds a level of germ reduction that air drying on a counter doesn’t match. Hand washing works just as well for cleaning, but you’ll need a dedicated bottle brush and a separate basin (not the kitchen sink itself, which can harbor bacteria). If you hand wash, you should also add a sanitizing step more often, since your water temperature is lower.
Whichever method you choose, store clean bottles in a clean, dry area with lids or covers on. Reassemble bottles only once all parts are completely dry, since trapped moisture encourages bacterial and mold growth.