An unopened can of Bobbie formula is good until the expiration date printed on the bottom of the container, typically 18 months to 2 years from the date of manufacture. Once you open the can, you have 30 days to use the powder. And once you mix a bottle, the clock gets much shorter.
Unopened Cans: Check the Bottom
As long as the seal is intact, Bobbie powder stays safe and nutritionally stable until the date stamped on the bottom of the can. Store unopened cans in a cool, dry indoor space, ideally between 65°F and 75°F. That means a pantry or kitchen cabinet works well, but a garage, car, or any spot exposed to direct sunlight or temperature swings does not. Never freeze formula powder or store it near heaters or vents.
After Opening: 30 Days
Once you break the foil seal on a can of Bobbie, use the powder within 30 days. After that point, exposure to air and moisture can degrade nutrients and increase the risk of contamination. Write the date you opened it on the lid with a marker so you don’t have to guess later.
Keep the opened can in the same cool, dry spot you’d store an unopened one, and press the plastic lid on tightly after every use. Don’t store the open can in the refrigerator. The moisture inside a fridge can cause the powder to clump and create an environment where bacteria are more likely to grow.
Mixed Formula: 2 Hours at Room Temperature
A prepared bottle that your baby hasn’t touched yet is safe at room temperature for up to 2 hours. If you won’t use it within that window, put it in the refrigerator right away, where it stays good for up to 24 hours. These timelines come from FDA handling guidelines and apply to all powdered infant formulas, Bobbie included.
The reason the window is so tight: milk-based formula is an ideal environment for bacterial growth. Research on Cronobacter, one of the most dangerous bacteria found in powdered formula, shows that at typical room temperature (around 72°F), bacteria can begin multiplying within about 3 hours and reach harmful levels in under 12 hours. At warmer temperatures closer to 95°F, that timeline compresses dramatically, with dangerous levels possible in under 6 hours. Refrigeration slows this process significantly, which is why chilling a bottle you’ve prepared in advance matters.
Once Your Baby Starts Drinking: 1 Hour
The moment your baby’s lips touch the bottle nipple, bacteria from their mouth enter the formula. At that point, you have 1 hour to finish the feeding. Whatever is left after that hour needs to be poured out, even if it looks and smells fine. This is true whether the bottle was served at room temperature or warmed up.
Don’t refrigerate a partially consumed bottle for a later feeding. The bacteria introduced during feeding multiply quickly in a nutrient-rich liquid, and refrigeration won’t make it safe again.
Warming Bottles Safely
Warming formula before feeding is entirely optional. If your baby prefers it warm, hold the bottle under running warm water until it reaches a comfortable temperature. Test it by placing a couple of drops on the back of your hand. It should feel lukewarm, not hot.
Never microwave a bottle of formula. Microwaves heat unevenly, creating hot spots in the liquid even when the outside of the bottle feels cool. These hot spots can seriously burn your baby’s mouth and throat. A warmed bottle follows the same 1-hour rule once feeding begins, and bacteria thrive even faster in a warm environment, so don’t let a warmed bottle sit out longer than necessary.
Transporting Formula on the Go
If you’re heading out, the simplest approach is to bring the powder and a bottle of water separately, then mix when your baby is ready to eat. This avoids any timing concerns entirely.
If you prefer to pre-mix, place the prepared bottle in an insulated cooler bag with ice packs to keep it cold. A pre-mixed bottle that hasn’t been refrigerated or kept cold needs to be used within 2 hours. A refrigerated bottle brought along in a cooler bag is good for up to 24 hours from the time you mixed it, as long as it stays cold and your baby hasn’t started drinking from it yet.
Quick Reference by Stage
- Unopened can: Good until the expiration date on the bottom (usually 18 months to 2 years from manufacture)
- Opened can (powder): 30 days, stored with the lid on in a cool, dry place
- Mixed bottle, untouched: 2 hours at room temperature, or 24 hours in the refrigerator
- Bottle baby has started drinking: 1 hour, then discard