How can you tell if American cheese is bad?

Determining if American cheese has gone bad can be tricky. Unlike many other cheeses that develop mold when spoiled, American cheese’s texture and appearance may not change much as it spoils. However, there are a few signs you can watch out for to know if your American cheese should be tossed.

Check the Expiration Date

The first and easiest way to tell if American cheese is bad is to check the expiration date printed on the packaging. American cheese, like most dairy products, will spoil past its printed expiration date. The expiration date will usually be stamped or printed on the side or bottom of the packaging.

For unopened packages of American cheese, you can generally trust this expiration date as an accurate gauge of when the cheese will go bad. However, once opened, American cheese will typically only last about 1-2 weeks past its printed date before spoiling.

Look for Mold

While mold is a very obvious sign of spoilage in many natural cheeses, it likely will not develop on American cheese. This pasteurized processed cheese product has a very low moisture content and high acidity that prevents mold growth.

However, if you do notice any furry mold spots or unusual colors on the cheese, it is certainly spoiled and should be discarded. The exception would be small white spots, which is most likely just harmless calcium lactate crystals.

Check the Texture

The texture of American cheese can be a good indicator of freshness. When opened, a fresh package of American cheese slices should feel slightly flexible and peelable. The slices should be smooth and not overly firm.

As American cheese spoils, it will become hard and brittle. The color may darken slightly and slices will be difficult to separate. If your cheese crumbles when bent rather than peeling into flexible slices, it has likely gone bad.

Smell the Cheese

Your nose is often the best tool for detecting spoiled foods. Give the cheese a good whiff when you first open a new package. Fresh American cheese should have a mild dairy scent, similar to processed cheese slices.

As it spoils, that inoffensive cheese smell will become stronger, sharper and more unpleasant. Rancid or “cheesy” odors are a sure sign the cheese has spoiled. If you detect a very unpleasant or strong smell, the cheese should be discarded.

Watch for Surface Moisture

Packages of American cheese slices should have a tight vacuum seal when purchased from the store. Once opened, the cheese may begin to dry out slightly but should not have moisture beads on the surface or appear wet.

If you notice any wetness, stickiness or shiny areas on the cheese slices, this indicates improper storage conditions and potential spoilage. Discard any American cheese that appears moist or weeping.

Check for Discoloration

The bright, pale orange color of American cheese is one of its signature traits. As it spoils, fading or darkening of the color can occur. While a deeper orange color alone doesn’t necessarily indicate spoilage, it can be one factor to consider.

Severe darkening with brown or gray spots would be a clear sign the cheese has spoiled. You may also notice the plastic packaging darken from an opaque white to a yellow tint as the contents spoil.

When in Doubt, Toss it Out

American cheese is inexpensive and sold everywhere, so it’s not worth taking risks with suspect cheese. If you notice any combination of the signs above – such as an expired date, funny texture, bad smell or discoloration – it’s best to just discard the cheese.

Getting sick from dairy products like American cheese is no fun. Trust your senses – if something seems off with the look, smell or feel of the cheese, throwing it out is the safest option.

Proper Storage for Maximum Freshness

When stored properly in the refrigerator, American cheese can maintain quality for longer periods before going bad. Here are some storage tips for keeping American cheese fresh:

  • Keep refrigerated at 40°F or below at all times.
  • If cheese comes in a pouch, roll or tightly seal after opening.
  • For sliced cheese, rewrap tightly in plastic wrap after use.
  • Avoid freezing American cheese if possible.
  • Store American cheese away from areas with high humidity in the refrigerator.
  • Consume within 1 week after opening for best quality.

Recognizing Other Signs of Spoilage

In addition to the common signs listed above, here are a few other things that may indicate your American cheese has spoiled:

  • Appearance: Oily, shiny patches on the surface or inside packaging.
  • Texture: Soft or mushy consistency.
  • Smell: Sour, yeasty or ammonia-like odor.
  • Taste: Bitter, sour or “off” flavors.
  • Safety: If mold is growing, do not smell the cheese or taste it.

What Types of American Cheese Are Most Prone to Spoilage?

The major types of American cheese include:

  • Cheese Slices: Individually wrapped slices found in the deli section. Most susceptible to drying out or developing off-flavors.
  • Cheese Blocks: Sold in plastic shrink-wrapped blocks to be sliced at home. Vulnerable to mold growth.
  • Cheese Spreads: Soft, squeezable versions in tubes or tubs. Can easily become rancid if left at room temperature.
  • Cheese Powders: Dehydrated cheese powder for popcorn, mac & cheese, etc. Typically has a long shelf life before spoiling.

In general, American cheese stored in solid block or sliced form is most prone to spoilage from improper storage. Keep the refrigerator temperature consistent, maintain a tight seal and avoid moisture contact whenever possible.

Can Spoiled American Cheese Make You Sick?

Consuming spoiled American cheese could potentially make you sick, depending on the type and extent of spoilage. Here are some possible illnesses:

Foodborne Illness

If American cheese becomes contaminated with dangerous bacteria like E. coli, Listeria or Salmonella and is then left at unsafe temperatures, the bacteria can multiply and cause foodborne illness when eaten. Symptoms may include nausea, vomiting, diarrhea, fever and cramps.

Food Poisoning

Bacterial growth can produce toxic chemicals in contaminated cheese that cause illness. Toxic mold can also grow under certain conditions. Symptoms of food poisoning from cheeses include headache, vertigo, cramps, weakness and tremors appearing quickly after ingestion.

Allergic Reaction

Cheese contains numerous allergens like milk proteins and mold spores. As cheese spoils, these increase and could trigger an allergic reaction in sensitive individuals. Symptoms like hives, wheezing, and vomiting could appear rapidly after eating spoiled cheese.


Checking for mold, monitoring changes in appearance, texture, and smell, and paying attention to expiration dates are all ways you can determine if your American cheese has gone bad. While this processed cheese has a long shelf life compared to more natural cheeses, it can still spoil eventually if not stored properly. When in doubt, do not eat American cheese that looks or smells suspicious.

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