Controlled Atmosphere Storage of Spotted Shrimp ( Pandalus platyceros )

Spotted shrimp ( Pandalus platyceros ) were stored head on and head off on melting ice in air and controlled atmosphere for 14 d to test effects of controlled atmosphere on storage life of the shrimp. Pure carbon dioxide was allowed to flow through the controlled atmosphere chamber at the rate of 0.5 L/min maintaining a 100% CO₂ atmosphere. Aerobic bacteria counts, ammonia, weight loss and sensory analyses were determined initially and after 7 and 14 d. Bacterial counts increased more rapidly and to higher levels in air pack than controlled atmosphere samples. The levels of ammonia were very low in the fresh shrimp and increased to 21 and 16 mg% in head-on and head-off air-pack samples, respectively. The levels reached only 12 and 6 mg% in similar samples stored in CO₂. Weight loss was greater for shrimp stored in CO₂ than in air. Sensory evaluation showed air-pack head-off samples to be unacceptable after 14 d of storage but CO₂-packed samples had only moderate discoloration and no detectable off-odors. These data show that spotted shrimp could be shipped on ice under controlled atmosphere to fresh fish markets.