Quick answer: Yes. Check the printed date on unopened bags and cans, then follow the maker’s shorter window after opening. Toss food with a rancid smell, mold, pests, or a swollen can.
Yes. Dog food expires, and the printed date applies only while the package stays sealed. This research-desk brief compares published dating rules; we did not open bags, culture samples, or time spoilage in a kitchen.
What the date on the bag actually means
The stamp is a quality deadline for a sealed package, not a forever-safe mark.
AAFCO writes the model pet-food label rules that many U.S. states adopt. AAFCO’s FAQ page says best-by dates on dry pet food are usually 6 or 12 months after manufacture.
That date is the maker’s claim about peak nutrition in an unopened bag. Purina’s storage page says every pet food and treat label carries a “best by” date. treats that date as the cutoff for using unopened food at peak nutrition.
Once you break the seal, that stamp is no longer the clock, because Purina’s page limits the date to unopened packaging.
Keep the lot number with the date on the bag. FDAPurina’s storage page says less than half of pet-food complaints include the lot number. That number helps FDA find when and where a batch was made.
How long unopened dog food lasts
Unopened dry food is usually dated in months, so buy a bag you can finish before the stamp.
IAMS’s page states unopened dry and wet dog foods usually expire between 12 months and two years after they are produced. That range is IAMS’s published rule, not a kitchen trial from our desk.
AAFCO’s 6- or 12-month dry-food window sits at the shorter end of the same idea. Use the date printed on your bag instead of a generic range.
HillPurina’s storage page says to discard an unopened bag after the printed best-before month. Its example stamp reads “best before April 2010,” and after April 1, 2010 that unopened bag should be discarded.
Cans follow the same discard rule on Hill’s page. The example can reads “best before December 2010,” and after December 1, 2010 that unopened can should be discarded.
A dented, swollen, or leaking can is still a discard, even if the stamp looks fine. FDA’s storage page lists a swollen or leaking can as a problem sign.
Do not stockpile prescription bags just because the date looks far out. Hill’s k/d with Chicken dry food ships in 8.5 lb, 17.6 lb, and 27.5 lb bags.
A 27.5 lb bag is a long eat-down for a small dog. If you need Hill’s Prescription Diet k/d, pick a size you can finish inside the opened window.
Opened bags and cans: three maker windows
After opening, use the maker’s own clock rather than the printed date on the bag.
Our research team analyzed three maker pages in September 2026 and called that pass the Pet Bench Date-Stamp Review. We compared published opened-use windows only and did not rank brands.
| Maker | Opened dry food | Opened wet food |
|---|---|---|
| 2 to 3 months if stored as directed | 3 days, sealed and refrigerated | |
| Hill’s | No opened-dry day count on its storage page | 5 to 7 days at 40–45°F |
| IAMS | About 6 weeks | Up to 7 days in the fridge |
Those numbers do not match, and that is the point. There is no single “opened bag lasts one month” rule across makers.
Purina’s page is the longest dry window we found, at two to three months. IAMS’s page is shorter, at about six weeks.
Hill’s storage page does not give an opened-kibble day count, but it does give a wet-food window of 5 to 7 days.
Wet food is the tighter clock, and Research suggests leftover canned food goes in the trash after three days. Hill’s says 5 to 7 days in a fridge set at 40–45°F.
IAMS says up to seven days if the leftover is covered and refrigerated. IAMS also sets a room-temperature limit of about two hours, after which you should not feed leftover wet food.
Hill’s adds a bowl rule for moist food and says to empty the bowl within 4 hours if the room is above 50°F.
If your dog eats a high-protein dog food, the same opened-bag clock still applies. Extra protein on the label does not extend the date.
Storage rules that keep the date honest
Heat, air, and a dirty bin can ruin food before the printed stamp.
FDAPurina’s storage page says to keep dry food and unopened cans in a cool, dry place under 80°F. Excess heat or moisture can break nutrients down.
Set the refrigerator to 40°F or below, then refrigerate leftover canned or pouched food, or throw it out.
Hill’s dry-food ceiling is higher than FDA’s line. HillPurina’s storage page says to store Science Diet and Prescription Diet bags under 100°F (38°C).
Hill’s also states that storage at 120°F (48°C) for more than 48 hours can speed up vitamin loss. That 48-hour heat spike is a maker rule, not a guess.
Hill’s unopened-can range is 50–100°F, and Hill’s does not suggest a garage or outdoor shed. IAMS’s page lists a pantry or garage as typical spots if the space stays cool, dry, and dark.
Those two maker pages disagree, so follow the stricter room and keep bags cool, dry, and indoors.
Keep kibble in the original bag, and FDAPurina’s storage page says to put the whole bag inside a clean bin when you can.
Save the UPC, lot number, product name, and “best by” date. Tape that panel to the bin if you must empty the bag.
Wash the bin between bags, because FDA says leftover fat and crumbs cling to the sides.
HillPurina’s storage page says many plastic bins can add an odor that dogs refuse. Hill’s accepts a clean metal bin with the original bag still inside.
Do not dump a new bag on top of old kibble. Finish the old food, then wash and dry the bin before you refill.
AAFCO’s FAQ page tells owners not to leave open bags sitting for months and to wash reusable bins between batches.
Signs the food has gone bad
Trust smell, sight, and the package, and do not trust a date alone.
FDA’s storage page lists these problem signs:
- A foul odor
- A swollen or leaking can or pouch
- A foreign object in the food
- A pet that becomes sick after eating
Hill’s and IAMS add the same everyday checks. Look for mold, moisture, or bugs, and smell for a rancid or paint-like fat odor.
IAMS says to discard food if it is past the printed date. Discard it as well if the smell is off even when the date still looks fine.
AAFCO’s FAQ page names two pantry pests, and Indian meal moths leave webbing along bag seams.
Sawtoothed grain beetles are tiny rust-colored insects in seams or at the bottom of a dumped bag. Discard infested food; do not sift bugs out and keep feeding.
A fat-heavy formula can turn sooner in heat. If the first ingredient is a fresh meat, or a concentrated meat meal, the fats still break down once air hits the bag.
The ingredient name does not reset the clock. If your dog ate food that smells wrong or came from a swollen can, stop that bag and call your veterinarian.
FDA’s storage page also asks you to report the product to FDA and to the maker. It lists CVM at 240-402-7002 for questions.
What this brief covers, and what it leaves out
We used one selection rule: commercial packages with a printed date and a maker storage page.
In scope:
- Dry kibble in sealed bags
- Canned or pouched wet food
- Opened-use windows printed by, Hill’s, and IAMS
- Storage temperatures published by FDA and those three makers
Out of scope:
- Homemade recipes
- Raw mixes you assemble at home
- Livestock feed
- Treats sold only as snacks, with no complete-and-balanced statement
AAFCO’s nutrient profiles list 37 nutritional parameters for dogs. Those numbers are why a “complete and balanced” bag is not the same as a treat.
Treats can still go stale, but they were not the subject of this brief.
We also skipped price tiers and ranked “best” lists, because dating does not change when a bag costs more.
Buy the smallest bag that matches how fast your dog eats, and match that size to the opened window in the table above. A 27.5 lb Hill’s k/d bag can outlast a six-week IAMS-style dry window for a small dog.
That mismatch is a sizing problem rather than a failure of the date stamp.
FAQ
Does dry dog food expire if the bag is still sealed?
Yes, a sealed bag still expires. AAFCO’s FAQ page says dry-food best-by dates are usually 6 or 12 months after manufacture. IAMS’s page puts unopened dry and wet food at 12 months to two years after production.
Can I feed dog food a week after the best-by date?
Purina’s page treats the “best by” date as the cutoff for unopened food at peak nutrition. HillPurina’s storage page says to discard an unopened bag or can after the printed best-before date. Our desk does not extend those dates, so use the shorter maker window once the package is open.
How long can opened wet dog food stay in the fridge?
Follow the brand you bought. Purina’s page says three days, sealed and chilled. HillPurina’s storage page says 5 to 7 days at 40–45°F, and IAMS allows up to seven days if leftover is covered. FDAPurina’s storage page says to set the fridge at 40°F or below.
Is it safe to store kibble in the garage?
HillPurina’s storage page says no and does not suggest a garage or outdoor shed. IAMS’s page lists a garage as a possible spot if it stays cool, dry, and dark. FDA’s storage page sets a hard ceiling of less than 80°F, so keep the bag indoors if a garage runs hotter.
What should I do with a swollen can?
Throw it out, because FDA’s storage page lists a swollen or leaking can as a problem sign. Do not taste it or feed it. Wash the can opener and the bowl, and report the lot number if you still have the label.
Does high-protein kibble expire faster?
Makers do not publish a separate date for high-protein formulas. Use the same sealed-package date and the same opened window. Fat still goes stale in air and heat, so a high-protein dog food is not exempt from the stamp.
Why keep the original bag if I use a bin?
FDA’s storage page wants the UPC, lot number, product name, and “best by” date nearby for complaints and recalls. Less than half of FDA pet-food complaints include the lot number, and the bag is where that number lives.
