How to Know if Leftover Stewed Tomatoes Are Bad When They Bubble

Any leftover food that has not been properly cooled and kept cold in a refrigerator can go bad. Most often when stewed tomatoes have bubbles coming up to their surface, it is a sign of fermentation. Fermentation is caused by microscopic organisms called yeast. They consume the tomatoes and the juice that it is in, and release alcohol and carbon dioxide, which makes the liquid bubble. Leftover stewed tomatoes that have been stored in your refrigerator for more than seven days may have gone bad and should be discarded.

Things You'll Need

• Food thermometer

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Instructions

• 1

  Insert a thermometer into your refrigerator. Wait an hour and check the temperature. If it is between 30 degrees and 40 degrees F, your refrigerator is running at the proper temperature and the food it contains is safe to eat.

• 2

  Check the temperature of the stewed tomatoes. If they are between 30 degrees and 40 degrees F, they should be safe to eat. If they are not, they are bad and you should discard them. Bubbling tomatoes that have been stored in the refrigerator at the proper temperature means that fermentation is occurring and the tomatoes have gone bad.

• 3

  Examine the container that the leftover stewed tomatoes are stored in. Check to see if the liquid has separated from the tomatoes and the tomatoes are floating on the top. If they are bubbling after being stored in a proper temperature in your refrigerator, it may be caused by the naturally occurring enzymes in the tomatoes that are causing the separation, which will move air out of the stewed tomatoes as the liquid separates. As long as the tomatoes have been properly stored at 30 degrees to 40 degrees F they should be safe to eat.

• 4

  Take a small taste of the bubbling tomatoes, but only if they were stored at the proper temperature. If they taste tangy or have a slight alcoholic after taste, they have gone bad.