Pancake syrup can sit out because of the ingredients it contains.

Chemical Food Preservation

There are three classes of chemical preservatives commonly used in foods:

  • Benzoates (such as sodium benzoate)
  • Nitrites (such as sodium nitrite)
  • Sulphites (such as sulphur dioxide)

If you look at the ingredient labels of different foods, you will frequently see these different types of chemicals used. Another common preservative that you will commonly see on food labels is sorbic acid. All of these chemicals either inhibit the activity of bacteria or kill the bacteria.