How can I tell if dry dog food is bad?

Quick answers

There are a few key signs that dry dog food has gone bad and should be thrown out:

  • It smells rancid, stale, or sour
  • It is past the expiration date or best by date on the bag
  • There is visible mold on the food
  • The kibble texture has changed – it’s sticky, mushy, or crumbling
  • Your dog refuses to eat it or gets sick after eating it

How to check for freshness

When you first open a new bag of dry dog food, take note of its appearance, texture, and smell. Fresh, high-quality kibble should have a crisp texture and pleasant aroma. It’s important to store dry dog food properly in a cool, dry place in an airtight container to maintain freshness. Here are some tips for checking whether opened dry food is still good:

  • Look at the expiration or best by date on the bag. Dry dog food usually stays fresh for 6-12 months after opening.
  • Check that the food has not passed the expiration date if one is printed on the bag.
  • Smell the food. It should have a normal kibble smell without any rancid or stale odors.
  • Examine the texture. The kibble should be crunchy and firm. Stale kibble becomes soft.
  • Look for any visible mold on the dog food. This is a clear sign it has spoiled.
  • See if the color has changed from its normal shade to a faded, dull color.
  • Taste a few pieces of kibble. Rancid kibble will have a distinct bitter, sour, or stale taste.

Trust your senses. If the dog food smells bad, looks moldy, or tastes off, it should be discarded. When in doubt, throw it out.

Changes in smell

Smell is one of the most important ways to check whether dry dog food has spoiled. When you first open a fresh bag, the kibble should have a pleasant, appetizing aroma. Over time, the oils in dry dog food can oxidize and go rancid, causing distinct changes in smell:

  • Rancid smell – Rotten, stale, sour odor like old cooking oil. This indicates the fats in the food have oxidized and spoiled.
  • Stale smell – Flat,cardboard-like odor. The oils have undergone oxidation during storage.
  • Moldy/musty smell – Earthy, dirty, decomposing smell. Sign of mold growth.
  • Metallic smell – Sharply chemical odor. Can mean the vitamin/mineral pre-mix has oxidized.

Any strange or unpleasant smells mean the dry dog food should be discarded. Rancid kibble can upset a dog’s stomach and provide little nutritional value.

Changes in appearance

Dry dog food can also undergo physical changes when it starts to spoil and go bad:

  • Color change – The kibble fades from its natural color to yellowish, greyish, or brownish tones.
  • Texture change – Fresh, crunchy kibble becomes soft, mushy, or powdery.
  • Mold growth – You may see fuzzy mold starting to grow.
  • Insect infestation – Weevils, moths, or beetles inside the bag.

Trust your eyes. Any unpleasant colors, soft textures, visible mold, or insects mean it’s time to throw the dry food out.

Changes in taste

Tasting a few pieces of kibble is another reliable test. Fresh, tasty kibble helps encourage picky dogs to eat. Look out for these taste changes:

  • Rancid taste – Rotten, sour, bitter flavor from oxidized oils.
  • Stale taste – Flat, cardboard-like, bland taste.
  • Moldy taste – Earthy, musty, dirt-like taste.
  • Metallic taste – Sharp chemical flavor from oxidized vitamins.

If you taste any unpleasant flavors, the dog food should be discarded. Even before the kibble smells or looks bad, rancid changes in taste can develop.

Watch your dog’s reaction

Pay attention to your dog when serving dry food from a newly-opened or older bag. Fresh, tasty kibble is usually gobbled right up. Here are some warning signs from your dog:

  • Disinterest in the food – Turns away from the food, refuses to eat.
  • Picky eating – Eats around the bad pieces.
  • Upset stomach – Vomiting, diarrhea, gas after eating.
  • Loss of appetite – Unwillingness to eat the kibble.

Dogs have a highly sensitive sense of smell and taste. If your dog refuses to eat or gets sick from the food, it has likely gone bad.

Check the expiration date

Reputable dog food companies print expiration or best by dates on the bag or can. Dry kibble generally lasts 6-12 months past the printed date. Canned food lasts 2-5 years unopened or 1-2 years after opening. Here are some tips for deciphering dates:

  • “Best by” indicates peak freshness, but food may still be good after date.
  • “Sell by” is for retailers to know when to pull from shelves.
  • “Use by” means don’t use after expiration.
  • “Born on” refers to production date.

While the date can serve as a helpful guide, your senses are the best tool for determining spoilage. If dry food smells, looks, or tastes bad, throw it out regardless of the date.

Watch for moisture and bugs

Dry dog food can start deteriorating due to excess moisture from improper storage. Here’s what to look out for:

  • Check bag seal – Moisture can enter if the bag is torn or left open.
  • Inspect storage area – Has anything leaked on the food? Is the area humid?
  • Look for clumping – Kibble starts sticking together from moisture.
  • See any bugs? – Weevils or moths attracted by moisture.

Discard clumpy or infested dog food which poses a choking risk. Keep food in a sealed container in a cool, dry pantry to avoid spoilage.

How to store dry dog food properly

Proper storage can help keep dry dog food fresh for months past the best by date. Follow these tips:

  • Use an airtight plastic, metal or glass container.
  • Store in a cool, dry spot around 55-75°F.
  • Keep food away from humid areas like the garage.
  • Wipe away moisture inside container before sealing.
  • Place container up high to avoid pests.
  • Buy smaller bags and use up quickly once opened.

Rotation is key – Serve from older bags first and incorporate fresh food every few weeks. Discard bags once the food is stale, clumpy, or infested.

Pantry storage tips

The pantry is an ideal storage spot. Follow these tips for keeping dry dog food fresher longer:

  • Place in an airtight container in a cool, dry pantry.
  • Keep container up high away from moisture.
  • Make sure food hasn’t expired before transferring to container.
  • Fold down bag tightly before sealing container.
  • Store unopened bags in a plastic bin or shelf.
  • Wipe out container periodically with dry cloth.

Freezer storage

The freezer can extend the shelf life. Follow proper guidelines:

  • Let kibble reach room temp before freezing to avoid moisture issues.
  • Place in air-tight container, bags are not moisture-proof.
  • Lay plastic wrap directly on surface to prevent freezer burn.
  • Defrost in fridge before serving.
  • Use frozen food within 6 months for best quality.

What happens when dogs eat spoiled dry food?

Eating rancid, moldy, or insect-infested kibble can cause a variety of health issues for dogs:

  • Vomiting and diarrhea – Stomach upset from spoiled fats and proteins.
  • Dehydration – Fluid loss from frequent vomiting or diarrhea.
  • Loss of appetite – Reluctance to eat due to bad taste.
  • Difficulty swallowing – Due to enlarged, sticky kibble.
  • Choking hazard – Moldy or insect-infested pieces.

Severe cases of food poisoning can even be life-threatening. Immediately transition your dog to a new food if symptoms occur after eating from an open bag.

How long after opening does dry dog food last?

An unopened bag of dry dog food can last up to a year past its best by date if stored properly. But once opened, the clock starts ticking:

  • Discard uneaten canned food after 2-3 days.
  • Discard dry food after 4 weeks in a container.
  • Discard dry food after 6 weeks in original bag.
  • Mark bags with date opened and use FIFO method.

Write the opening date on bags since it can be hard to remember. Refrigerating unused portions can extend freshness by a few days.

Will expired dry dog food make a dog sick?

Dogs can sometimes tolerate expired dry food without getting sick. However, the risk increases over time:

  • Within a month – Low risk of illness.
  • 2-3 months – Moderate risk of upset stomach.
  • Over 6 months – High risk of vomiting, diarrhea, choking.
  • Over a year – Severe illness can occur.

Even before the expiration date, rancid fats and bacterial growth can cause issues. When in doubt, throw it out. Feeding expired food is never worth the risk.

Can spoiled dry dog food kill a dog?

In severe cases, yes – eating moldy, insect-infested, or heavily spoiled dog food can potentially be fatal. Here are some high risk dangers:

  • Toxins from mold – Certain molds like aflatoxin can be lethal in high doses.
  • Choking – On softened, enlarged or moldy kibble.
  • Severe vomiting/diarrhea leading to dehydration – Especially in puppies, small dogs, and seniors.
  • Blood sugar crash – From going off food due to bad taste.

While rare, dogs have died from eating extremely spoiled dog food. It’s not worth the risk. Dispose of any kibble you suspect may be bad.


Checking for signs of spoilage like smell, texture, taste, and appearance is the best way to determine if dry dog food has gone bad. Watch for changes from its normal fresh state, and discard any food that smells rancid, looks moldy, or makes your dog sick. With proper cool, dry storage in an airtight container, unopened kibble can stay fresh for months past the best by date. But once opened, use within 4-6 weeks for maximum safety and quality.

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