Infant formula is the only food that federal rules require to carry a date. The “Use by” date is the last day the manufacturer guarantees the formula contains at least the amount of each nutrient on the label and is of acceptable quality.
Don't buy or use formula after its use-by date. FDA, CDC and USDA all say so.
What the regulation says
Under 21 CFR 107.20(c), every infant formula label must carry a Use by date, “the blank to be filled in with the month and year selected by the manufacturer, packer, or distributor” based on tests or other information showing that until that date, stored and prepared as the label directs, the formula will:
- “when consumed, contain not less than the quantity of each nutrient, as set forth on its label”; and
- “otherwise be of an acceptable quality (e.g., pass through an ordinary bottle nipple).”
So the date may show only a month and year. The guarantee also assumes the storage and preparation directions on the label are followed, and the same regulation requires the label to warn that “prolonged storage at excessive temperatures should be avoided.”
Why this date is different from every other food date
For most foods, USDA says a product whose date passes at home should still be safe and wholesome if handled properly. Infant formula is the stated exception. Its date isn't about flavor. For a baby who may get all of their nutrition from formula, the labeled nutrient amounts are the point, and after the use-by date the manufacturer no longer guarantees them. FDA's guidance: “Don't use a package or container of infant formula after this date.”
That also makes it the exception to the advice on the rest of this site about looking past best-by dates. See how it compares with other use-by dates in what use by means, and with every other phrase in sell by vs use by vs best by.
After opening and mixing: the shorter clocks
The use-by date covers a sealed container. Once formula is opened or prepared, these limits from FDA and CDC apply, whichever comes first:
| Situation | Guidance | Source |
|---|---|---|
| Opened container of powdered formula | Typically use within 1 month. Write the opening date on the lid; store it tightly closed in a cool, dry place, not the fridge. | FDA |
| Prepared bottle at room temperature | Use within 2 hours of preparation and within 1 hour from when feeding begins | CDC |
| Prepared bottle you won't use within 2 hours | Refrigerate immediately and use within 24 hours | CDC, FDA |
| Formula left in the bottle after a feeding | Throw it out. Don't save it for later. | CDC, FDA |
| Freezing formula | Not recommended; the parts of the formula can separate | FDA |
Ready-to-feed and liquid concentrate formulas can have their own instructions once opened, so follow the container's label. FDA explains why leftovers go: the formula “now contains the baby's saliva, which can cause bacteria to grow.”
Reading the date on the can
Look for the words USE BY next to the date. Other codes printed nearby are often lot numbers rather than dates. If you're unsure what a printed date means, you can type it into the expiration date decoder. Before buying, check the date, and skip any container that is damaged or leaking.
Questions people ask
Can I use infant formula a day or two after the use-by date?
No. FDA says not to use a container of infant formula after its use-by date, and CDC says never to use formula after it. The manufacturer guarantees the nutrient content and quality only up to that date.
How long is powdered formula good after opening?
FDA says an opened container of powdered formula typically needs to be used within one month. Write the date you opened it on the lid, keep the lid tight, and store it in a cool, dry place, not the refrigerator. Check your formula's label, and never use it past the use-by date, even if the month isn't up.
How long can a prepared bottle of formula sit out?
CDC says to use prepared formula within 2 hours of preparing it and within 1 hour of when feeding begins. If you won't start using it within 2 hours, put it in the fridge right away and use it within 24 hours. Throw out whatever is left in the bottle after a feeding.
Sources
- 21 CFR 107.20: Directions for use — Code of Federal Regulations, via Cornell Legal Information Institute
- Handling Infant Formula Safely: What You Need to Know — U.S. Food and Drug Administration
- Infant Formula Preparation and Storage — Centers for Disease Control and Prevention
- Food Product Dating — USDA Food Safety and Inspection Service