Nitrites Nitrates Cured Food Additives
Curing Meat and Fish
Sodium nitrite is used for the curing of meat because it prevents bacterial growth and, in a reaction with the meat's myoglobin, gives the product a red color. During the curing process, nitrites are converted to nitric oxide, which binds the myoglobin into a red color. Without nitrites, hotdogs and bacon would be a very unappetizing grayish color, but maybe that would be a good thing, discouraging us from eating all that fatty food. There are nitrite free hotdogs on the market but few people buy them because of their color; cancer be damned we want our hotdogs to be pink!
What is the difference between nitrates and nitrites? Both Nitrates and nitrites are permitted in curing meat and poultry with the exception of bacon, where Nitrate use is prohibited. Sodium nitrite is commonly used in the USA and everywhere else in the world. Nitrate actually is changed to nitrite by bacterial action during processing and storage so our food is always cured with nitrites, even when the process starts with nitrates. The advantage to processors is to use nitrites directly because they can better control dosages and processes. Nitrites are effective at lower temperatures in the range of 36 to 40 degrees F. while nitrates require temperatures of 46 to 50 degrees F. thus the growth of bacteria is slower when using nitrites.
The most common sources for nitrites/nitrates in meat processing are potassium nitrate, (which you may know as Saltpeter) and sodium nitrate, (also known as Chile saltpeter.) These substances are also used in fertilizers, bomb making and pyrotechnics.
Information about sulfites here: http://hubpages.com/hub/Sulfites-Sulfate-and-Sulfur-Food-Additives
Toxic Nitrites in Celery?
Because of the toxicity of nitrite, (Pure sodium nitrite is a powerful poison, as you need only about ⅓ of a teaspoon to put your life in danger), the maximum allowed nitrite concentration in meat products is 200 ppm. During cooking, nitrites in meat can react with degradation products of amino acids, forming nitrosamines, which are known carcinogens. A 2007 study by Columbia University also suggests a link between eating cured meats and chronic obstructive pulmonary disease with nitrites suggested as a possible cause. Although the link between nitrosamines and cancer has been proven in lab animals, it not yet certain that nitrites in processed foods are causing cancer. An enormous amount of indirect evidence does indicate that nitrosamines are human carcinogens. However, it is difficult to evaluate the risk of cancer from daily exposure of 1 microgram from foods and beverages. Research is ongoing and it is up to the consumer to make informed decisions about their own diet.
Almost all preserved meats and fish contain some level of nitrites and as is usual with additives; nitrites are a double-edged sword. Nitrates inhibit the growth of Botulism, delay rancidity, protect flavor and gives us that pink color we are accustomed to in preserved meat. The obvious downside is cancer, but that’s a distant possibility to think about when flavor, rancidity and food poisoning are immediate concerns. Without nitrites and nitrates, some foods would be impossible to make because of the Botulinum toxin. Botulism bacteria (Clostridium Botulinum) need an anaerobic (air free) environment to thrive and multiply; salami, and other dried sausages all provide ideal environments for the growth of the bacteria and the toxins they produce. Botulism, while not a common food borne illness is a deadly paralytic disease, which is always treated as a medical emergency. The Botulinum toxin is destroyed by cooking, but most items affected do not get cooked, does anyone cook salami? Botulism is the concern when you see a bulging can of food, always discard a can like that, and no tasting to see if it is okay! Cooking will however also kill the Botulinum bacteria and prevent them from producing their toxin in the first place. Time and temperature control are critical when processing meats.
Nitrites in Vegetables
Heavy applications of nitrogen fertilizer can cause nitrates to accumulate in vegetables. But applying too much nitrogen fertilizer may be bad for human health. Once we consume these vegetables, nitrates may be converted into nitrites. Organic vegetables are no safer than conventional crops because the nitrogen can come from compost as well as chemical fertilizers.
High levels of nitrate in food or drinking water are known to be dangerous to babies. During the first three months of life they cause the blood to carry less oxygen, and the infant may suffocate. For older children and adults, the consumption of high levels of nitrate is linked to esophageal cancer, due to the formation of nitrosamines.
For the cook in the kitchen, occasionally we see a ground beef mixture that stays pink even though it was well cooked. If you have ever encountered this when making meatloaf or meatballs, you may be able to blame it on the celery. This was demonstrated conclusively to me while working in a hospital kitchen. Hospitals are very careful with food safety and we always checked our temperatures to avoid food poisoning. One day, the meatloaf stayed pink no matter how long I cooked it. We finally sent samples to a lab to find out what was going on. The lab report came back stating that nitrites were present and the cause of the pink color. Celery is often grown with large amounts of nitrogen fertilizer and mixing it with ground beef causes the same reaction that keeps bacon pink.
We have 5 thousand years of history using nitrites/nitrates to preserve foods. The practice of curing food with salt began in remote antiquity. The process is all about removing moisture from the food being preserved. (Mummies owe everything to this process although their salt was natron but that’s a different topic.) Food was preserved with common salt, sodium chloride, but unknown to these folks was that the salt they used was contaminated with nitrates. It was not until the middle ages when saltpeter was discovered as a separate chemical and it became a dominant part of food preservation. In those days, the amount of nitrate/nitrite present in the food was as much as 50 times as much as is used currently. The advent of refrigeration went a long way to lower the amounts of nitrites/nitrates used in food.
In 1980, nitrosamines were discovered in beer. The nitrosamine was not formed during the brewing process--it was formed by direct-fire drying of barley malt, an ingredient used in making beer. By converting the process from direct-fire drying to indirect-fire drying, the formation of nitrosamines wire markedly reduced. Beer now contains only 2% of the amount of dimethylnitrosamine that was present 20 years ago.
Nitrates in vegetables
According to the University of Minnesota Extension, vegetables actually account for 90 percent of nitrate intake. The amount of nitrite in our meats pales in comparison with the amounts of Nitrates that are found in vegetables that we consume every day Leafy and root vegetables like spinach, beets, radishes, celery and cabbage naturally contain high levels of nitrates that partly convert to nitrites during digestion. The heavy application of nitrogen-based fertilizers increases the amount of nitrates in vegetables but once again, the evidence does not point to these vegetables causing cancer. Actually, a diet rich in vegetables is still considered healthier than a diet of meat and potatoes. If you are concerned and wish to limit or reduce the amount of nitrates in vegetables, boil them, high temperature like those on your backyard grill are conducive to the formation of nitrosamines while boiling will dilute them.
Vegetable Nitrate mg/kg spinach 1631 - beetroot 1211 - lettuces 1051 – cabbages 338 - potatoes 155 – carrots 97
cauliflowers 86 - brussel sprouts 59 - onions 48 - tomatoes 17
When we used salt with a higher nitrate content the meat had a different taste and color
- Sodium nitrate in meat: A heart disease risk factor? - Mayo Clinic
- Nitrates in Vegetables
- Scientific Opinion of : Nitrate in vegetables
- Nitrosamines and Cancer