Preservatives are used to keep foods fresh, retard spoiling and inhibit growth of harmful microorganisms, according to the Science Daily website. Antimicrobial chemicals retard growth of bacteria, mold and yeasts. Antioxidant chemicals slow oxidation of fats and lipids that cause rancidity. A third group of chemicals fight enzymes that promote natural ripening of fruits and vegetables after they are picked. Read each food label to identify what, if any, preservatives are used in a product.
Sulfites
Sulfites are a large group of preservatives used in vinegar, fruit juices, dried fruit and other foods. Sulfur dioxide has antimicrobial and antioxidant properties that keeps food fresh and blocks growth of microorganisms, respectively, according to the Science Daily website. Research by Babgaleh Timbo of the Center of Food Safety and Applied Nutrition at the U.S. Food and Drug Administration published in the "Journal of Food Protection" in 2004 reviewed and reported on adverse reactions from sulfite-sensitive individuals. The research reports the FDA prohibits use of sulfites on fresh fruits and vegetables, except potatoes, and requires that the presence of sulfites used in processing or from a component in the food be declared on food labels. Despite regulations, the FDA has recalled foods containing undeclared sulfites and received reports of adverse reactions allegedly due to eating foods containing undeclared sulfites.
Benzoates
Benzoates, found naturally in cranberries, are antimicrobial chemicals that primarily fight fungi in areas with low acidity, according to the Science Daily website. Benzoates inhibit growth of molds, yeast and bacteria in acidic liquids and drinks, such as vinegar, fruit juice, soda and carbonated beverages, according to the Diet Health website. Sodium benzoate is used in foods with a pH below 3.6 such as soy sauce, duck sauce and salad dressings. Potassium benzoate is used to preserve foods with a pH below 4.5 such as various fruit juices and soft drinks.
Propionates
Propionates are chemicals similar to propionic acid, a natural preservative found in foods such as strawberries, apples, grains and cheese, according to the Science Daily website. Propionates are antimicrobial chemicals that help to keep bakery products fresh by inhibiting the growth of bread molds and spores of a bacterium that makes bread inedible. Unlike benzoates, propionates do not require an acidic environment to be effective, making propionates ideal for preserving bakery products, according to the Diet Health website. Calcium propionate, sodium propionate and potassium propionate are common types of propionates used as food preservatives.
Nitrites and Nitrates
Nitrites and nitrates are chemicals used to preserve and cure meats and block botulism bacteria from growing, according to the Science Daily website. Nitrites and nitrates give meats a fresh pink color, preventing them from turning brown. Inside the body, nitrites and nitrates produce carcinogenic agents called nitrosamines. Research by M.H. Ward published in the "International Journal of Cancer" in June 2000 discovered that nitrite and nitrosamine intake from consumption of preserved foods during childhood may increase risk of nasopharyngeal cancer in adulthood. Dietary nitrosamines from high consumption of processed meat may increase risk of stomach cancer, according to research by S.C. Larsson published in the "International Journal of Cancer" in August 2006.
References
- Science Daily: Focusing on Preservatives: How They Keep Food Fresh
- "Journal of Food Protection"; Sulfites--a Food and Drug Administration Review of Recalls and Reported Adverse Events; Timbo, B.; Aug 2004
- Diet Health: Artificial Preservatives
- "International Journal of Cancer"; Dietary Exposure to Nitrite and Nitrosamines and Risk of Nasopharyngeal Carcinoma; Ward, M.H.; Jun 1 2000
- "International Journal of Cancer"; Processed Meat Consumption, Dietary Nitrosamines and Stomach Cancer Risk; Larsson, S.C.; Aug 15 2006
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