N-nitrosamines in processed meats: Exposure, formation and mitigation strategies

Nitrite and nitrate have been widely used in the preservation of meat products for the effective antimicrobial action against several pathogenic bacteria such as Clostridium botulinum, Salmonella and mesophilic bacteria. However, they can further react with secondary amines in meat products and produce noxious compounds called nitrosamines during thermal processing. N-nitrosamines are divided into volatile N-nitrosamines and non-volatile N-nitrosamines, among which volatile N-nitrosamines are a group of highly hazardous chemical carcinogens whose carcinogenicity and teratogenicity have led to widespread concern. Owing to their occurrence in daily diet, it is of great significance to suppress their formation and toxicity on human health without causing adverse effects on food flavors. In this paper, the formation mechanism and toxicity of nitrosamines are provided. Potential mitigations can be carried out from the perspectives of precursors in raw materials, processing conditions as well as exogenous additives. Moreover, promoting the degradation of nitrosamines is an effective approach. The potential health risks associated with nitrosamines are described. Different intervention substances, such as polyphenols, vitamins and various plant extracts are summarized, discussing their impact on various toxicity of nitrosamines. The purpose of this review is to provide theoretical guidance on the control of nitrosamines generation and deleterious effects, so as to promote the development of meat processing and practical production.