Opened Kendamil powder is generally used within four weeks, while prepared formula follows a much shorter clock. FDA guidance says use prepared formula within two hours of making it, refrigerate an unused bottle immediately and use it within 24 hours, and discard leftovers within one hour after feeding begins.
Those clocks answer different questions. The four-week rule does not apply to a mixed bottle, and refrigeration does not rescue formula the baby has already drunk from.
Label-first rule: Storage directions can change. Write the opening date on the lid and follow the strictest current instruction on your exact can, plus any individual guidance from the baby's clinician.
Kendamil storage chart
Kendamil powder and prepared-formula storage timeline
| Situation | Working limit | What to do |
|---|---|---|
| Unopened powder | Until the printed use-by date when stored correctly | Keep sealed, cool, dry, undamaged, and away from heat and sunlight |
| Opened powder | Kendamil says within 4 weeks; exact can controls | Write the open date, close the lid tightly, keep scoop and powder dry |
| Freshly prepared bottle at room temperature | Within 2 hours of preparation | Feed promptly or refrigerate immediately if unused |
| Prepared but never-started bottle in refrigerator | Within 24 hours under FDA guidance | Refrigerate immediately, not after it has sat out |
| Bottle after feeding starts | Within 1 hour | Discard leftovers; do not refrigerate for later |
| Powder or prepared formula in freezer | Do not freeze | Freezing can separate prepared formula and humidity damages powder |
The FDA's current infant-formula handling guidance supplies the prepared-bottle limits. Kendamil's powder storage guidance says to use opened powder within four weeks and keep it cool, dry, and tightly closed.
Unopened Kendamil: use the printed date
An unopened can is only good through its printed use-by date when it remains sealed, undamaged, and correctly stored. The FDA requires infant formula to carry a use-by date because the manufacturer guarantees nutrient content and quality through that date.
Do not use a can with:
- a broken or suspicious seal;
- swelling, rust, leakage, or severe dents;
- moisture or insects;
- an expired use-by date; or
- a lot included in an official safety notice.
“It smells normal” is not a way to extend an infant-formula date.
Opened Kendamil powder: four weeks, not forever
Kendamil says opened powder should be used within four weeks. The FDA says opened powdered formula typically needs to be used within one month, but the manufacturer's label controls.
On opening day:
- write the date on the lid;
- keep the original scoop with the original can;
- close the lid tightly after every use;
- store the can in a clean, cool, dry cabinet; and
- keep the scoop, rim, lid, and powder dry.
Do not top a new can with old powder. That loses the lot code and opening date and can transfer moisture or contamination.
Where to store Kendamil powder
Kendamil recommends a clean, cool, dry place away from direct sunlight, stoves, ovens, heating ducts, and hot-water pipes. Its general guidance gives a preferred range of roughly 13–24°C (55–75°F).
Do not keep the powder can in the refrigerator. Humidity can cause clumping. Do not freeze it.
A kitchen cabinet away from steam and heat is usually more appropriate than the counter beside a kettle or dishwasher.
Freshly mixed Kendamil: the two-hour clock
FDA guidance says prepared infant formula should be used within two hours of preparation. Kendamil recommends preparing feeds fresh when possible.
Start the clock when the formula is mixed, not when the baby first looks hungry. If the bottle sits at room temperature, do not reset the clock by cooling or reheating it later.
Refrigerated prepared formula: only if it was unused and chilled promptly
If a freshly prepared bottle will not be used within two hours, FDA guidance says to put it in the refrigerator immediately and use it within 24 hours.
That does not mean leaving the bottle on the counter for most of the two-hour window and then refrigerating it. Prompt refrigeration limits bacterial growth.
Kendamil's preference is fresh-on-demand preparation. If your routine requires batch or advance preparation, confirm the plan with the exact can and pediatrician—especially for a baby under two months, born prematurely, or with a weakened immune system.
Once feeding begins: one hour, then discard
The current U.S. Kendamil pages say to use the formula within one hour after feeding begins and discard the rest. The reason is saliva: bacteria from the baby's mouth enter the bottle and can multiply.
Do not:
- put a partly finished bottle back in the refrigerator;
- add fresh formula to the leftover bottle;
- reheat and offer it at the next feed; or
- judge safety by smell or appearance.
What if the bottle was warmed?
Warming does not create a new storage window. Keep the original preparation and feeding-start times.
Never microwave formula. Warm a capped bottle with warm water if desired, keep water away from the nipple, test the temperature on the wrist, and discard it on schedule.
A simple labeling system
For the powder can, write:
Opened: August 23
Use by: September 20 or the earlier can date
For a prepared bottle stored immediately in the refrigerator, label the mix date and time. Do not use a bottle label to override the manufacturer's instructions or keep a started feed.
When to throw formula away early
Discard powder or prepared formula before the normal deadline when:
- the seal or container is damaged;
- water, a wet scoop, or a foreign object entered the powder;
- the powder has an unusual odor, color, pests, or unexpected clumping;
- storage temperature was uncontrolled;
- a refrigerator lost power and the bottle was not kept safely cold;
- the lot is subject to a recall or safety alert; or
- you cannot tell when it was opened or mixed.
When infant-formula safety is uncertain, throwing it away is safer than guessing.
Bottom line
Keep dry Kendamil powder out of the refrigerator, use opened powder within the can's stated window—currently four weeks in Kendamil's guidance—and treat mixed formula as a perishable food. Two hours after preparation, 24 hours only when promptly refrigerated and untouched, and one hour after feeding begins are separate limits.
For the mixing sequence, use How to Prepare Kendamil Formula. For texture problems, see Why Kendamil Is Foamy or Clumpy.
Sources checked August 2026: CDC formula preparation and storage guidance, FDA infant formula guidance for parents and caregivers, and Kendamil’s formula storage guidance. Follow the shortest applicable limit on the exact can.