Bacterial Spoilage of Processed Sea Scallop ( Placopecten magellanicus ) Meats

During extended summer trips (16 days), mid-Atlantic sea scallop ( Placopecten magellanicus ) meats hand-shucked at sea and stowed on ice in linen bags become unmarketable because of a spoilage process called "yellowing." Studies were performed to evaluate spoilage of shucked scallop meats by psychrotrophic bacteria under conditions of simulated and actual commercial stowage, and to examine the effects of various prestowage washes and bag materials on this process. A scallop medium and enumeration method based on measuring bacterial populations at the bag/meat interface were developed for this purpose. Results showed that large populations of psychrotrophic bacteria (> 10¹⁰ culturable cells per in²) grew on the meats and meat/bag interfaces at 2°C over a 15-day stowage period. Associated with this growth was a rise in surface pH and the appearance and gradual increase of fluorescence on cut muscle surfaces and bags under long-wave UV illumination. Freshly shucked meat surfaces never fluoresced. Of the various deck treatments and bag materials tested, only treatment with 1.25% lactic acid solution retarded pH and bacterial density increases.