How to Determine if Pizza Sauce Is Bad?

How to Determine if Pizza Sauce Is Bad? (Image: GreenArtPhotography/iStock/GettyImages)

One ingredient in your pizza makes or breaks it: the sauce. A mouthwatering rich tomato-based sauce adds just the right touch of tangy zest and texture to your homemade pizza. Whether it's sweet or spicy, called "spaghetti sauce" or "pizza sauce," the sauce combines with the melting cheese to create a memorable meal your whole family will love.

However, if your delicious sauce has gone bad, it can ruin your entire pizza. Expired spaghetti sauce not only tastes terrible, it can make you and your family sick too. To avoid sabotaging your homemade pizza with bad sauce, look for these signs that indicate it has spoiled.

Check for Visible Mold on the Spaghetti Sauce Lid

The most telling sign that your pizza or spaghetti sauce has spoiled is visible green, black or white mold on the sauce lid. You'll likely see the fuzzy mold on the inside of the lid and even some mold on the top of the sauce too. Mold on a jar lid indicates that the mold has spread throughout the sauce itself, and it's not safe to eat, according to the United States Department of Agriculture.

Remember: Mold can grow on sauce even if it's refrigerated. And even if you scrape away the mold, it's still not safe to eat. That's because foods like pizza and pasta sauce that contain a high amount of water grow mold filaments even below the surface of the mold. Bacteria also may be lurking in there, so it's best to discard the sauce and purchase a new jar if you see mold on the lid.

Smell and Taste the Sauce

If you open your jar of spaghetti sauce and smell an unpleasant aroma, that odor likely means your sauce has gone bad. Another indicator that your sauce is no longer good is if it tastes sour, unpleasantly tangy, bitter or is generally unappetizing.

Even if you don't see mold in the sauce, it can still be present, which accounts for the off-taste. Also check for color changes that are unusual, another indicator of expired pasta sauce and possible mold.

Check for Broken Seals

Before you taste or smell your pizza sauce to see if it's still good, inspect the jar or can for a few key indicators of a problem:

  • The jar seal is broken
  • The can is dented or swollen
  • Bubbling foam appears when you open it

If you notice any of these signs, the jar of sauce has gone bad and should not be used.

Although tomatoes are an acidic food, if they haven't been properly canned or the seal on your jar has been broken, it's possible that your sauce has become contaminated with Clostridium botulinum, a potentially toxic bacteria. Even tasting or smelling the tomato sauce can make you very sick if ingested or inhaled, warns the Centers for Disease Control and Prevention.

Find the Expiration Date

Your can of pizza or spaghetti sauce will have an expiration date printed on it, usually on the bottom of the can or lid of the jar. If this date has passed, then your sauce has possibly gone bad. These dates are determined by the manufacturer and indicate when the product inside is at its peak freshness.

Although canned sauce may still be edible beyond the expiration date, the date is a good indicator that the sauce inside isn't going to be very fresh or tasty. To ensure a delicious pizza, purchase a new sauce can or jar at its peak of flavor.

Keep Track of Open Sauce

Even if your can of sauce isn't past its expiration date, if you've opened it, it still could have gone bad. Sauce kept in the refrigerator between 35 and 40 degrees Fahrenheit lasts around five to seven days and in the freezer at 0F for about three months.

If you've left the sauce out for longer than two hours at temperatures above 40F or more than one hour at temperatures above 90F, the sauce has likely gone bad and should be tossed, warns the CDC. Mold and bacteria flourish at these temperatures, making the product dangerous to eat.

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