Organoleptic, Bacterial, and Chemical Characteristics of Penaeid Shrimp Subjected to Short-Term High-Temperature...

White shrimp ( Penaeus setiferus ) were held at 0, 10, 20, 30, 37, and 44 C for 3, 6, and 24 h. Serious quality deterioration, as evidenced by off-color development (red and orange pigmentation) and off-odor development, was beginning to occur in shrimp held for 3 h at 30, 37, and 44 C, for 6 h at 20 C and for 24 h at 10 C. Red color development was evident in shrimp held at 30 and 37 C, orange color in those held at 44 C. Putrid odors appeared more rapidly in shrimp held at 37 than at 44 C where shrimp developed cooked-shrimp odors. Large increases in bacterial counts at 30-44 C (after 6 and 24 h) were usually accompanied by putrid odors. Tissue pH changes were erratic and small. Total volatile nitrogen (TVN), free amino acid nitrogen (AA-N), and urea production increased with storage temperature during the 3- and 6-h storage experiments. Musty and cooked-shrimp off-odors developed in the shrimp as a result of chemical and/or enzymic activity while putrid and sour odors were produced by bacteria growing in the shrimp.