Freshly harvested white shrimp (Penaeus setiferus) were taken from 13 locations on the northwestern coastline of the Gulf of Mexico. Freshly harvested brown shrimp (Penaeus aztecus) were taken from 3 different water depths near Port Aransas, Tex. Brown shrimp taken from commercial fishing boats at time of landing also were examined. Samples were analyzed for amino nitrogen (AA-N), NH3, total volatile nitrogen (TVN), trimethylamine nitrogen (TMN), bacterial content, and pH. A portion of each sample was placed on sterile ice and allowed to spoil. Spoilage odors appeared in white sea-shrimp after storage for 11–50 days, for brown sea-shrimp in 20–30 days, and in brown boat-shrimp after 0–15 days. Both TVN and AA-N varied considerably from sample to sample and did not show a consistent pattern of change during iced storage. TVN/AA-N ratios increased as samples spoiled. TVN/AA-N ratios greater than 1.3 mg N/mm indicated a short shelf-life of boat shrimp. TMN production was evident in boat-shrimp samples (4 out of 9 samples) with high TVN levels. Bacterial counts of fresh shrimp did not exceed 104/g. Nine of the 10 boat-shrimp samples had counts in excess of 106/g. Counts of samples spoiled on sterile ice ranged from 2 × 106 to 1010/g. The estimated reduction of the maximum potential shelf-life of boat-shrimp by handling and storage was 0–15 days.
1Published with the approval of the Director of the Texas Agricultural Experiment Station, College Station.