Before the development of refrigeration, people the world over used similar methods for preserving meat: salting, smoking, and air drying. Although curing is no longer essential in industrialized countries, our taste for salty, smoky f lavors persists. Smoking preserves meat and fish both by slow cooking at a low temperature and by treatment with chemicals in the smoke. The method is now used primarily for flavor—for example, the distinctive hickory or oak aroma that is associated with smoked bacon, and the mesquite and other aromatic wood chips that are used to enhance the taste of grilled foods.
Air curing, or preserving by dehydration, has been used for thousands of years. Prosciutto is an air-cured meat. Drying generally concentrates some nutrients, especially minerals, but the vitamin content of dried meat is much less than that of fresh. Salt-cured meats, such as country ham or bacon, are preserved either in a brine solution or a dry salt bed. The salt draws water from the meat and from bacteria and molds through the process of osmosis. While the meat remains wholesome, but the Microorganisms shrivel and die.
All cold cuts and cured and smoked meats are high in sodium, frequently more than 30% of RDA. Many, especially cold cuts and sausages, also contain fillers such as corn syrup or cereal (and therefore should be avoided by people with celiac disease or gluten intolerance). Some, especially those made from pork or beef, are also high in saturated fats; turkey or chicken versions usually have lower levels of fat.
The major health risks of cured meat are,
High risk of Cancer:
The reddish pink color of cured meats, including the cold cuts at the delicounter, is due to the presence of nitrities, chemicals that enhance the effect of salt by inhibiting bacterial growth and slowing fat oxidation. Nitrites can cause tumors in laboratory animals that consume it in very high doses. But the meat industry and the government insist that nitrites should be retained because they are extremely effective against Clostridium botulinum,the micro organism that causes botulin poisoning, or botulism.
High blood pressure and cardiovascular disease
Because of their high sodium content, cold cuts and other cured meats can increase blood pressure, a leading risk for heart problems.
Tyramine, a metabolic product of the amino acid tyrosine, is found at high concentrations in cured meats. It can trigger migraine attacks in susceptible people.
Listeriosis and toxoplasmosis
Listeria, a bacteria found in deli meats, infects an estimated 2,500people per year with listeriosis, which causes flulike symptoms. The bacterium is killed by the pasteurization process and cooking; but some deli foods are contaminated after processing. While the infection is rarely serious for healthy adults, pregnant women should limit the amount of cold cuts they eat because it poses a serious risk to the baby. Uncooked air-cured or salt-cured meats may be infected with the toxoplasmosis parasite, which can have similar risks for fetuses.