FOOD SAFETY: SAFETY OF SODIUM NITRITE IN CURED MEATS

Whether it's by smoking, curing or salting, humans have been preserving meats since ancient times in order to make them tastier and safe to eat at a later time.

Additives used during the curing process provide meats with their distinctive flavor and appearance, as well as maintain freshness and safety from dangerous bacteria.

While the benefits of the curing process are well known, consumers and scientists have raised questions about the safety and necessity of these substances over the past 30 years, especially since some studies in the 1970s associated certain preservatives with cancer in laboratory animals, while other later studies suggested an association between cured meat consumption and illnesses in children. One of the substances of concern was the preserving agent known as sodium nitrite.

After decades of exhaustive review of studies about the use of sodium nitrite in curing meats, the Food and Drug Administration and the U.S. Department of Agriculture believe that nitrite is a safe ingredient and is not associated with cancers in humans at the levels used.

Curing involves adding a number of ingredients – including salt, sodium nitrite and sometimes sugars, seasonings, phosphates and ascorbates (which includes vitamin C) – to meats, poultry and fish. The curing process controls the growth of harmful bacteria that can cause serious illnesses and improves the safety of food. It especially protects against Clostridium botulinum, a deadly microorganism that can cause one of the deadliest food-borne diseases: botulism. Since the routine use of sodium nitrite by meat processors, no cases of botulism have been associated with cured meats.

Types of cured meat include:

· Hot dogs and some sausages

· Luncheon meats

· Bacon

· Ham

Sodium nitrite is a food additive that has been used for decades to preserve meats, poultry and fish.

When used alone or in conjunction with sodium nitrate, nitrite gives cured meats their characteristic reddish-pink color, flavor and texture. Nitrite and salt also inhibit the outgrowth of C. botulinum.

More than 85 percent of a person's daily intake of nitrite comes from nitrate in green, leafy vegetables or root vegetables, such as lettuce, spinach and carrots, and some drinking water. At most, about 5 percent of a person's daily intake comes from cured meats.

Sodium nitrite has a number of biological functions in the body. Your body needs a certain level of nitrite in order to fight bacteria found in the stomach and protect against bacterial illnesses, such as gastroenteritis. In fact, your body produces nitrite from sodium nitrate through a naturally occurring chemical process in the saliva.

Sodium nitrate that is consumed is absorbed quickly in the body and the majority is eliminated from the body through urine in approximately five hours. A portion of the nitrate is secreted into the salivary glands, and a small percentage (approximately 5 percent) of the salivary nitrate is reduced to nitrite in the saliva and travels down the gastrointestinal tract to the stomach.

In the stomach, nitrite can form nitric oxide. Nitric oxide has been found to serve as a biological messenger in important physiological functions, such as healing wounds and burns, controlling blood pressure and boosting immunity.

The body generates more nitrite through this process than is ingested through food. Some scientists believe that the body's natural production of nitrite from foods may be a part of its defense mechanism since nitrite inhibits the growth of harmful bacteria and prevents deadly food-borne diseases.

Some of the concern about nitrite grew out of the fact that nitrites could potentially react in the stomach with certain chemicals that are released during protein digestion to produce a chemical known as N-nitrosamines. N-nitrosamines has been associated with cancer in animals.

There also were a number of studies during the 1970s that linked the consumption of nitrite with cancer in laboratory animals or associated the consumption of cured meats with illnesses in children. As a result of some lingering concerns about nitrite safety, the FDA and the USDA commissioned a comprehensive review of sodium nitrite's role as a food additive.

The results were two scientific reports from the National Academy of Sciences (issued in 1981 and 1982). The 1981 report stated that nitrate does not cause cancer, although some population studies have found an association between high exposure to nitrate levels and certain cancers. Also, nitrite does not act directly as a cancer-causing agent in animals. The NAS recommended that both these issues be researched further. The NAS also recommended that people's exposure to both nitrates and nitrites be reduced as much as possible without jeopardizing the protection against botulism.

The 1982 NAS report investigated alternatives to the use of nitrate in foods. Although there were some promising results, a workable alternative has not yet been found.

Two important actions in the year 2000 have reinforced the message that the use of sodium nitrite in cured meats is safe and is not associated with cancer risk in humans.

The first is a thorough review of the results of sodium nitrite studies by the National Toxicology Program, which undertook the review at the request of the FDA. After carefully considering all the evidence presented, the NTP Board of Scientific Counselors voted unanimously in May 2000 that the evidence showed that sodium nitrite does not cause cancer in male rats, male mice or female rats. While they found "equivocal evidence" in the forestomachs of female mice, the scientists have determined that the finding is not relevant to human health because humans do not have forestomachs. This comprehensive review by NTP shows that sodium nitrite does not cause cancer in laboratory animals, even when they are fed massive doses throughout the animals' lifetime.

The second action occurred in the state of California, where a panel of independent expert toxicologists reviewing almost 100 scientific publications about sodium nitrite voted that the evidence does not show that sodium nitrite causes developmental or reproductive toxicity. If found by the DART committee to be harmful, sodium nitrite would have been listed under the state's Proposition 65 law, which was enacted to protect citizens against known cancer-causing agents and reproductive toxicants.

The FDA and USDA have deemed sodium nitrite and sodium nitrate, or the combination, as safe to use as a preservative for meat and poultry at specific, regulated levels. By law, the curing process must result in no more than 200 parts per million (ppm) of sodium nitrite in the finished meat or poultry product.

The cured meat industry made substantial changes to the manufacturing process in the past 20 years to address some of the concerns about nitrite in cured meats. It has stopped using sodium nitrate (except for some specialty meats) in major meat processes and reduced the use of nitrite in the processing of cured meats. Residual levels of nitrite found in nitrite-cured meats have decreased in the past 20 years and now average one-tenth of what the regulations actually allow. The industry also has increased the use of two other substances – ascorbate and erythorbate – in the curing process, which are known to deplete residual nitrite and inhibit the production of N-nitrosamines.

In today's hectic lifestyle, ready-to-eat foods and other modern advances of preparing meals offer convenience and save time.

Whole, fresh foods, which include the recommended daily servings of fresh fruits and vegetables, are an important part of a balanced diet. So is protein. Served in the context of a well-balanced meal, parents can add cured meats to the family menu in moderation with confidence without fear of its safety.