Effects of two thawing methods on the shelf life of cephalopod mollusks

Thawing is a critical step in cephalopod processing, as it affects physicochemical parameters, microbial stability, and overall product quality. Current European and national guidelines recommend consuming or processing thawed cephalopods within 24 hours, a restriction that often results in substantial food waste. This study evaluated the impact of two thawing methods - rapid water-immersion thawing and slow refrigerated thawing - on the quality of Octopus vulgaris and Illex argentinus over 48 hours of refrigerated storage. A total of 12 animals (6 per species) were thawed using either method (3 rapidly thawed and 3 slowly thawed per species), and sensory quality (organoleptic examination and electronic nose), pH, thiobarbituric acid reactive substances, total volatile basic nitrogen, trimethylamine, color, and microbiological indices (mesophilic counts, coagulase-positive staphylococci, Enterobacteriaceae, and coliforms) were analyzed at T0 (day of thawing), T1 (24 hours post-thawing), and T2 (48 hours post-thawing). The results indicate that rapid thawing more effectively preserved the chemical and sensory characteristics of I. argentinus compared to O. vulgaris up to 48 hours post-thawing, whereas slow thawing better preserved the microbiological quality of both species over the same period. Rapid thawing also maintained microbiological parameters within acceptable limits, suggesting that the trends observed beyond the currently recommended 24 hours after thawing may offer useful information for future studies aimed at better defining post-thaw shelf life evolution in cephalopods thawed with different methods.