TMA (Trimethylamine) 具腥臭味故很容易由官能判定其鮮度。判定鮮度標準以BN及pH較易有判定之規範。TMA值若愈高,相對其鮮度亦愈差。檢驗方法請參考下列文獻:AOCO OFFICIAL METHODS OF ANALYSIS (1995) AOCO Official Method 971.14 Trimethylamine Nitrogen in Seafood. Fish and Other Marine Products chapter 35, 7.