• Preservatives can make food last longer, but might make you sick.vegetable preservation image by Leonid Nyshko from Fotolia.com
  
  Preservatives have allowed us to keep food without being harmed by toxins created by spoilage. The preservative salt was so important to the Romans that soldiers were given a salt allowance as payment, and its Latin name, salis, is the basis of the word salary. Still, some preservatives may cause harm, and knowing which ones to limit or avoid can help you avoid potential adverse health effects.
  
  

Sulfites

• Sulfites are used to preserve seafoods, cheeses, wines and foods containing fruit or vegetables. Common sulfites include potassium bisulfite, potassium metabisulfite, sodium bisulfite, sodium metabisulfite, sodium sulfite, and sulfur dioxide. The chemicals can slow bacterial growth and allow treated fruits to maintain optimal color. Sulfite allergies affect approximately five percent of asthmatics, and sensitive individuals may suffer an asthma attack if exposed to sulfites at low levels of concentration. Due to this risk, the U.S. Food & Drug Administration (FDA) requires that foods with concentrations higher than 10 parts per million (ppm) be labeled. You are advised to avoid foods containing more than 50 ppm if you have previously experienced a negative reaction to sulfites.
  
  

Nitrates

• Sodium nitrate is used to preserve and maintain color in fish and meat that has been smoked or canned. This chemical reacts with stomach acids to produce nitrosamine, which has been linked to cancer in lab animals. The United States Department of Agriculture (USDA) prohibits nitrates from being used in baby foods due this risk, and Dr. Christine Gerbstadt from the American Dietetic Association listed sodium nitrate as an additive to avoid. Additionally, according to a study headed by Suzanne M de la Monte of the Rhode Island Hospital Department of Neuropathology, nitrosamine can also contribute to deleterious effects produced by type 2 diabetes and Alzheimer's disease.
  
  

Diacetyl

• While most of the possible risk from food additives is directly linked to consumption, preservatives can also cause harm when inhaled. Diacetyl is a synthetic version of one of the chemicals that gives butter its flavor, and is added to cheeses and microwave popcorn. Inhalation can result in a lung condition called bronchiolitis obliterans, which is also known as popcorn lung. The condition is most often found in workers who process microwave popcorn, and in cooks who use butter sprays in restaurants. However, in 2007, Wayne Watson was diagnosed with the disease, after eating two bags of microwave popcorn a night for several years. ConAgra, a company that makes several popular brands of popcorn, stopped using diacetyl in response to concerns posed by employees.