Sensory, Histological, and Bacteriological Changes in Flat Oysters, Ostrea edulis L., during Different Storage Conditions

Abstract

Flat oysters, Ostrea edulis, were emersed and stored for 23 d in freshwater ice and cold stored without ice. A control group was maintained in running seawater. Death, histological changes, bacterial growth, and changes in sensory profile were measured and described. Death of the oysters could be determined by measuring tissue pH. The sensory profiles of iced and cold-stored oysters were significantly different from the controls, and changes in sensory profile correlated with the appearance of spoilage bacteria and degradation of digestive tissues. Changes were most pronounced in iced specimens. Freshness of the oysters was correlated to the smell of sea, fresh fish, and shellfish and the appearance of the mantle.

Changes in the microbiological and physicochemical quality of high-pressure-treated oysters (Crassostrea gigas) during chilled storage

“…The pH of fresh purified oysters was 6.33, consistent with previous reports (Aaraas et al, 2004;Cruz-Romero et al, 2004, 2007. Immediately after HP treatment, oyster tissue had significantly (P < 0.05) higher pH values than that of untreated oysters (Table 2).…”

“…In untreated oysters, demonstration of a stable pH during storage indicates maintenance of extracellular pH (Aaraas et al, 2004); this is typical for many intertidal bivalve molluscs (Newell, 1970) to maintain respiratory gas exchange and thus tolerate emersion during low tide. The active compensation for a progressive acidosis stops when death occurs and the pH rapidly falls; therefore decreasing pH is a clear indicator of death (Aaraas et al, 2004). Cook (1991) stated that oysters (with liquor) are classified as being of good quality if their pH is P6.0.…”

Sensory Qualities of Oysters Unaltered by a Short Exposure to Combined Elevated pCO2 and Temperature

“…As explained by Cochet et al (2015), the use of descriptive sensory techniques for oysters can be difficult considering that oysters reared under the same conditions display a wide range of different sensory profiles (Aaraas et al, 2004), making it difficult to decipher sensory changes due to experimental treatment. The batch of oysters used for our experiment was of consistent age and size class, however there were slight natural morphological variations between individuals, which could have had an influence on their sensory profiles.…”

“…This technique is considered an accurate quality predictor (Reineccius, 1991;Chang et al, 1998), and has been used extensively for oyster quality assessments (Aaraas et al, 2004;Cao et al, 2009;Buzin et al, 2011;Cochet et al, 2015).…”

“…This type of model is commonly used for analysis of sensory studies data (Aaraas et al, 2004;Buzin et al, 2011;Cochet et al, 2015). Homogeneity of variance was checked using Cochran's C test.…”