“…Indole has been used as a spoilage indicator for shrimp and other crustaceans (Snellings, Takenaka, Kim-Hayes, & Miller, 2003). Other compounds produced during spoilage include hydrogen sulfide, dimethyl sulfide, and methyl mercaptan from sulfur-containing amino acids; various amines, ammonia, skatole, putrescine, and cadaverine from amino acids; lower fatty acids from sugars such as glucose and ribose; carbonyl compounds from lipids (Avery & Lamprecht, 1988;Smith, Nickelson, Martin, & Finne, 1984;Watts & Brown, 1982). Loss of freshness, which often precedes microbial spoilage, primarily involves autolytic reactions controlled by endogenous enzymes present in the muscle tissue as well as those leaching from the gut (Ashie et al, 1996).…”