Nitrates and Nitrites

Nitrates and Nitrites chemical compounds used in the curing of meats, for example to make ham, bacon, some sausages, and silverside of beef. The type traditionally used is saltpetre, potassium nitrate. So-called Chile saltpetre, sodium nitrate, is also employed; it is cheaper and slightly stronger.

As the curing process continues, bacteria decompose a little of the nitrate into nitrite. Nitrites react with myoglobin, a protein in the meat, turning it pink and producing the characteristic colour of cured meat products. At the same time, even smaller amounts of compounds known as nitrosamines are produced. These are suspected of causing cancer. There are strict limits on the nitrite content of cured meats, intended to keep nitrosamines down to safe levels.