2-Methylimidazole (2-MI) and 4-methylimidazole (4-MI) are undesired byproducts generated in Maillard reaction where carbohydrates (glucose, lactose, and so on) react with amino groups or ammonia (Casal et al., 2002; Moretton et al., 2011; Wang and Schnute, 2012). These 2 compounds have been identified in ammoni- ated hay forage for livestock animals and milk from cows fed ammoniated forage (Chan et al., 2006). 2-Me- thylimidazole and 4-MI have also been determined in many other kinds of food, such as soy sauce and beve