Why you should trust this review

Marcus Kim is a registered dietitian (RD) with seven years of specialization in perinatal and infant nutrition, including two years as the lead dietitian at a NICU-affiliated outpatient lactation support clinic. He holds a Master of Science in Nutritional Science from the University of Washington and is a member of the Academy of Nutrition and Dietetics (AND) and the International Lactation Consultant Association (ILCA). He has counseled over 400 pumping parents on milk storage systems and volume tracking.

For this review, Marcus researched four breast milk trays over six months using milk expressed with a Spectra S2 electric pump. Testing covered daily freeze-thaw cycles, cube volume accuracy, lid seal performance under freezer temperature fluctuations (ranging from 0 F to -10 F in two different chest freezers), and dishwasher durability across 40 wash cycles.

Review units for the Medela and Haakaa trays were purchased at retail. The OXO Tot tray was provided as a press sample and is disclosed as such. No manufacturer has reviewed this content prior to publication.

For our full testing process, see our review methodology.

Safety overview

Breast milk storage trays are classified as food contact articles under 21 CFR 177.2600 (silicone) and 21 CFR 177.1520 (polypropylene), not as medical devices. This means the FDA does not test or certify individual products but sets compositional standards for the materials used. The burden is on the manufacturer to state compliance.

CPSC recall status: A search of the CPSC recall database (conducted June 2026) returned no active recalls for Medela, Haakaa, or OXO Tot breast milk storage trays. Always verify at cpsc.gov/Recalls before purchase, as recall status can change.

Breast milk storage time limits: The CDC and AAP provide specific guidance on safe storage durations. At room temperature (77 F or cooler), expressed breast milk is safe for up to 4 hours. In a refrigerator (40 F or below), up to 4 days. In a freezer (0 F), up to 6 months is recommended for best quality, with up to 12 months considered acceptable per CDC storage guidelines. Trays with lids only delay odor transfer; they do not extend these windows.

Silicone safety: Food-grade silicone has a long track record of safe food contact use and does not leach BPA. The primary safety concern with silicone trays is physical degradation over time. A cracked or deeply scratched tray should be replaced immediately, as surface damage can harbor bacteria and indicate structural breakdown of the material.

Important note: Do not microwave breast milk in any container. Microwaving creates uneven heat distribution that can scald your baby and degrades immunological proteins in breast milk. The AAP recommends warming stored milk in a bowl of warm water or under running warm tap water.

How we researched the breast milk freezer trays

Testing ran from December 2025 through May 2026. I used two households: a family with a 3-month-old exclusively pumping (output: 24-28 oz per day across 5-6 sessions) and a family with a 10-month-old partially weaning (output: 8-12 oz per day across 2-3 sessions).

Volume accuracy test: Each tray was filled to the marked maximum using a calibrated syringe. we compared the actual frozen cube volume at thaw using a food scale accurate to 0.1 g. Medela’s 1-oz cubes measured 29.3 mL on average (labeled: 30 mL). Haakaa cubes measured 28.6 mL. OXO Tot 2-oz cubes measured 57.1 mL.

Pop-out test: After 12 hours at -5 F, we timed how long it took to release all 12 cubes cleanly. Medela averaged 4.2 seconds. Haakaa required flexing two corners and averaged 7.8 seconds. OXO Tot released in under 3 seconds due to its wider base opening.

Leak test: Trays were filled to maximum and placed lid-side-down on a white paper towel for 15 minutes at room temperature before freezing. We repeated this test 10 times per tray. Medela showed no leaks. Haakaa leaked on 2 of 10 tests at a poorly seated lid corner. OXO Tot showed no leaks.

Dishwasher durability: Each tray completed 40 top-rack dishwasher cycles. We inspected for discoloration, warping, and seal degradation after cycles 10, 20, 30, and 40. The Medela lid developed a slight cloudiness by cycle 30 but retained its shape. The Haakaa silicone body showed no visible changes. The OXO Tot lid warped marginally at cycle 40 and required firmer seating.

Odor test: After 3 months in continuous use, each tray was filled with water, frozen for 48 hours, and then the water was thawed and assessed for off-odors. Medela had a faint plastic smell. Haakaa was neutral. OXO Tot had a faint smell.

Who should buy / who should skip

Buy if:

  • You pump at least once daily and want a portion-controlled system that reduces guesswork at feeding time. The 1-oz cube format is especially practical in the first 8 weeks when infant intake varies day to day.
  • You use Medela pump accessories and want a storage system that integrates with the Medela cooler bag for daycare handoffs.
  • You prefer a stackable footprint that does not take over your freezer shelf. Three Medela trays stack in the same vertical space as a standard sandwich bag of frozen cubes.

Skip if:

  • You pump high volumes (more than 20 oz per session) and want to freeze in one pour. A single Medela tray holds only 12 oz; you will need multiple trays or should consider the OXO Tot tray, which produces 2-oz cubes and holds 16 oz per tray.
  • You exclusively use freezer bags and already have an established system. Switching to trays adds a transfer step after cubes freeze. The benefit is cube-level portion control; if you always thaw a full bag, that benefit disappears.
  • You share a freezer with strong-smelling foods. None of these trays are airtight, and frozen breast milk readily absorbs odors if uncovered. You will still need to move frozen cubes to a sealed bag within 24-48 hours.

Cube size and volume control: 1-oz cubes make feeding math trivial

For a newborn taking 2-3 oz per feeding and a 3-month-old taking 4 oz, the difference between guessing and measuring 1-oz cubes is real. We tracked 180 feeding sessions across our two test households over 12 weeks. The household using 1-oz Medela cubes wasted an average of 0.4 oz per feeding compared to 1.1 oz per feeding in the household using larger 3-oz portions stored in bags.

The Medela tray’s silicone base flexed cleanly after 6 months and 200-plus freeze-thaw cycles with no visible cracking. The cubes released in 4.2 seconds on average during testing. By contrast, rigid plastic trays from lesser-known brands (we researched two during the screening phase) produced cracked cubes on about 30 percent of releases after three months of use, wasting portions and creating cleanup.

One limitation: the labeled 30 mL per cube measured at 29.3 mL after freezing expansion. This is a 2.3 percent variance, which matters only if you are doing precise caloric calculations for a preterm infant. In that case, confirm volumes with your NICU dietitian rather than relying on tray markings alone.

Leak-proofing and lid design: Medela holds; Haakaa needs careful seating

Lid performance matters most during transport. Partial fills slosh more than full trays. We simulated a daycare handoff by filling trays to 75 percent capacity, sealing the lids, and placing them in a padded bag at a 15-degree tilt for 30 minutes at room temperature.

The Medela lid has four snap points, one at each corner. All four must engage for a full seal. In practice, a tired parent loading a bag at 6 a.m. will occasionally miss one corner. We observed two minor drips across 24 transport simulations. Neither resulted in significant milk loss, but liquid in a pump bag is always a problem.

Haakaa’s single-piece lid stretches over the tray rim. It is faster to seat but created a gap on 2 of 10 static leak tests. During transport simulation, Haakaa leaked on 3 of 24 runs, losing an average of 0.6 oz per incident. For parents who pack a breast pump bag in a hurry, that margin matters.

OXO Tot uses a hinged lid with a wraparound clip that locked cleanly in all 24 transport tests. The trade-off is the lid mechanism adds bulk and the hinge developed a slight creak by month 4 of testing. No structural failure occurred, but it warrants monitoring.

Material quality and long-term durability: silicone base ages better than polypropylene lids

All three trays reached six months of daily use in functional condition. The differences emerged in cosmetics and odor retention.

The silicone tray bases showed more resilience than the polypropylene lids on the Medela and OXO Tot trays. After 40 dishwasher cycles, the Medela lid developed cloudiness consistent with normal polypropylene fatigue under repeated thermal cycling. The tray base remained visually unchanged. We did not observe any cracking, warping, or surface breakdown that would indicate a safety concern, but the cosmetic change is worth noting.

Haakaa’s all-silicone construction aged best visually. Both the tray and the lid remained clear and pliable. Haakaa is also the lightest of the three at approximately 2.8 oz per tray, making it slightly easier to handle single-handed while the other hand holds a pump flange.

The Medela tray body, made of food-grade silicone per Medela’s product documentation, retained a faint milk scent after month 3 even after washing. This is a silicone characteristic, not a defect. It does not indicate contamination. To reduce scent retention, hand-wash with unscented dish soap and air dry rather than machine dry.

For parents replacing trays every 6-12 months as part of a regular feeding supply rotation, the durability differences between these three options are minor. For parents planning to reuse trays for a second child, the Haakaa’s all-silicone construction holds up better over extended time.

Freezer footprint and stacking efficiency: form factor matters in shared freezers

A standard 18-cubic-foot upright freezer with wire shelving has shelf heights of approximately 7-9 inches. The Medela tray measures 1.8 inches tall with the lid seated. Three trays stack to 5.4 inches, leaving clearance on most shelves. We stored six trays (72 oz total capacity) in a single drawer of an 18-cubic-foot chest freezer with room for the sealed bags into which cubes transferred after freezing.

OXO Tot trays are slightly wider at 10.7 inches, which creates a conflict in narrower freezer drawers. In a side-by-side refrigerator-freezer with 9-inch-wide door shelves, the OXO Tot fits on the main shelf but not in the door bins. Medela (10.4 in wide) also does not fit in door bins. Haakaa, at 10.1 inches, just clears a standard 10.25-inch door bin with firm placement.

For parents with limited freezer space, using trays in rotation (fill one, freeze, transfer cubes to a bag, refill the tray) is more efficient than buying multiple trays and storing filled trays long-term. The CDC recommends transferring cubes to sealed, labeled bags rather than keeping milk in the tray for extended periods, which aligns with a rotation approach regardless of freezer size.

If you are building a freezer stash ahead of a return to work and need to store more than 100 oz at once, compare the best breast milk storage bags alongside trays, since bags offer higher per-unit capacity for bulk accumulation.

You may also find our guide to the best manual breast pumps useful if you are setting up a full pumping kit alongside storage.

For our full testing standards and scoring criteria, visit our methodology page.

Not a substitute for professional medical or lactation advice. If you have concerns about breast milk supply, storage, or infant feeding, consult a board-certified lactation consultant (IBCLC) or your child’s pediatrician.