People have used saltpetre, potassium nitrate, for more than 2,000 years. It was used as an ingredient to cure or pickle meat, a an element of gun powder and as a fertiliser, according to the University of Minnesota. The multifaceted chemical is composed of potassium, nitrogen and oxygen, and one of its longest-lasting application is as a food preservative. While meat can be cured with natural ingredients, the United States Department of Agriculture (USDA) requires food processors to label meat cured without sodium nitrite or nitrate as uncured.
Nitrites found in vegetables can function as a natural substitute for saltpetre. Typically, nitrites naturally occur in leafy green vegetables, but celery juice or powder is favoured for organic meat curing because the pigment in them barely alters the colour of meat, and it maintains a mild flavour, according to the American Meat Science Association. Organic processing of cured meat is similar to chemical processing, but the shelf life of organically cured meat is shorter.
Sea salt is produced when seawater evaporates, and usually includes minerals native to the water source. These minerals add little in nutritive value, but can alter the taste and colour of the salt. The difference in sea salt and table salt primarily consists of the difference in processing, taste and texture, but sea salt also contains the nitrates useful in natural meat cures. As an alternative to saltpetre, the natural nitrates in sea salt can change to nitrites when they encounter certain bacteria, replicating the characteristics of traditionally cured meats, according to the American Meat Institute.
Beet juice gets its deep red or purple colour from pigments called betalains, which offer anti-inflammatory and antioxidant properties, notes The World's Healthiest Foods website. Beets contain a multitude of health benefits, including heart disease, certain cancers and birth defects. Beet juice can substitute for saltpetre as a means to cure meat in a chemically free way. Like celery juice or powder, beet juice may naturally contain nitrates that, when they come into contact with some types of bacteria, can change to nitrites. In addition to the ability to mimic chemical curing agents, beet juice can add colour to the meat in a way similar to pink salt. As with the other natural curing agents, the shelf life of meat cured with beet juice is shorter than chemically cured meat.