Jams, jellies, fruit butters, and preserves are shelf-stable food products. They contain high amounts of sugar and acid which lower the water activity and pH, respectively, of the product to minimize the growth of bacteria. Moisture migration, mold growth, and oxidation are reduced by hermetically sealing the jar. Important to the safety of jams and jellies is ensuring the pH of the product is below 4.6. Below this pH, Clostridium botulinum, a very serious human pathogen, cannot produce its deadly toxin.