N-nitrosocompounds (NOCs): As chemo-hazards in muscle foods

Nitrite and/or nitrate have been widely used in muscle food processing as a main curing agent, though it can produce several kinds of carcinogenic N-nitrosocompounds (NOCs) reacting with amine components of muscle protein. N-nitrosodimethylamine (NDMA), N- nitrosodiethlamine (NDEA), N-nitrosopyrrolidine (NPYR) and N-nitrosopipperidine (NPIP) are major nitrosamines commonly occur in cured meat products. Additionally, N-Nitrosothiazolidine (NTHZ) and N- nitrosodibenzylamine (NDBzA) could form in smoked and rubber contaminated meat products respectively. The formation of NOCs in muscle foods greatly depend on several factors such as nitrite concentration, processing conditions, ingredients as well as environmental, ecological and biological factors. Excess dietary nitrite intake through muscle food is one of the major sources of endogenous nitrosamines formation in human stomach, which could pose several cancer risks especially gastric and esophageal. However, NOC inhibitors such as organic acids, vitamins, phenolic compounds, nitrate reducing bacteria and ã-irradiation have been found effective inhibitors to NOCs. This review mainly focuses on the occurrence of NOCs, mechanism, influencing factors, deleterious effects and feasible inhibitors to NOCs in muscle food products.