Under what specific condition do nitrites react with amino acids to form nitrosamines?

When exposed to high heat, such as frying bacon or grilling sausages.

The primary toxicological concern regarding nitrates and nitrites arises not from their direct presence but from the chemical reactions they undergo during cooking. When cured meats containing nitrites are subjected to high thermal energy, such as during frying bacon or grilling sausages, the nitrites become highly reactive. In this high-heat environment, they can readily interact with amino acids, which are naturally occurring protein building blocks within the meat tissue. This interaction leads to the synthesis of nitrosamines, a class of compounds recognized as known or suspected carcinogens, which significantly increases the long-term health risk associated with consuming these meats cooked at high temperatures.