The Sous Vide Cooking of Mediterranean Mussel (Mytilus galloprovincialis): Safety and Quality Assessment

Abstract

This study involves an investigation of the effects of various cooking temperatures, freeze-thaw processes, and food preservatives on the quality and shelf-life of sous vide Mediterranean mussels. Cooking temperatures of 80 °C or above significantly improved the microbiological quality, with bacterial counts remaining within the acceptability range for human consumption even after 21 days of refrigerated storage. Fast freezing followed by slow thawing preserved the highest moisture content, potentially improving texture. Sensory analysis revealed that refrigerated sous vide mussels maintained a comparable taste to freshly cooked samples. Frozen samples reheated via microwaving exhibited more intense flavour than pan-reheated or fresh mussels. Food additives, including citric acid, potassium benzoate, and potassium sorbate, alone or in combination with grape seed oil, significantly reduced total volatile basic nitrogen and thiobarbituric acid-reactive substances during 28 days of storage, indicating decreased spoilage and lipid oxidation. Mussels with a combination of these additives registered a nitrogen content as low as 22 mg of N/100g after 28 days, well below the limit of acceptability (<35 mg of N/100g). Food additives also inhibited bacterial growth, with mesophilic bacteria count below 3.35 Log CFU/g after 28 days, compared with 5.37 Log CFU/g in control samples. This study provides valuable insights for developing optimal cooking and preservation methods for sous vide cooked seafood, underscoring the need for further research on optimal cooking and freeze-thaw protocols for various seafood types.

Keywords: Mytilus galloprovincialis; seafood; semi-preserved food; sensory analysis; shelf life; sous vide.

Figure 1

Shear force values of sous vide refrigerated (+4 °C) mussels cooked at different temperatures and measured at different times (■ t0; ● t21). Different letters indicate significant differences within groups (p < 0.05); asterisks indicate significant differences between groups.

Figure 2

Changes in total volatile basic nitrogen (TVB-N expressed as mg of nitrogen/100 g of mussels, (A) and 2-thiobarbituric acid-reactive substances (mg of malondialdehyde/kg, (B) of four different thermal treatments of sous vide cooked mussels stored at 4 °C as a function of storage time. Different letters represents a significant difference (p < 0.05).

Figure 3

Spider plot of specific sensory attributes of refrigerated sous vide mussels (left) and frozen sous vide mussels (right). Control refers to fresh-cooked mussels. Asterisk (*) for each attribute indicates a significant difference (p < 0.05) compared with the control.

Figure 4

Effects of food additives on total volatile basic nitrogen (TVB-N, (A)) and 2-thiobarbituric acid (mg of malondialdehyde/kg, (B)) of mussels cooked sous vide during 28 days of refrigerated storage (+4 °C). AC = treatment using citric acid; BC = citric acid and grape seed oil; CM = treatment using citric acid, potassium benzoate, and potassium sorbate; Control = no food additives. Legends refers to the time of analysis (0 days to 28 days). Different letters represents a significant difference (p < 0.05).