Effect of High Hydrostatic Pressure Processing on Biochemical Characteristics, Bacterial Counts, and Color of the Red Claw Crayfish Cherax quadricarinatus

The effects of high hydrostatic pressure (HHP) processing at 200 MPa, 400 MPa, and 600 MPa on the proximate composition, inactivation of bacteria, and color of the red claw crayfish Cherax quadricarinatus were evaluated. High hydrostatic pressure processing resulted in complete shelling and a significant decrease in the moisture content (P < 0.05), whereas no significant differences were observed in the content of ash, crude protein, and crude lipid, except for the crude lipid content between 200 MPa and 600 MPa groups (P < 0.05). After pressurization, the Escherichia coli, Vibrio vulnificus, and Vibrio parahaemolyticus counts decreased significantly with the increase of pressure, even to an undetected level for V. vulnificus and V. parahaemolyticus at 400 and 600 MPa (P < 0.05), respectively. During 30-d storage at 4°C and –20°C, the counts of these three bacterial species increased significantly with increased storage time and temperature. After HHP processing, a* value changed substantially, whereas L* and b* values had little change for meat. The total color difference (ΔE*) suggested that the HHP-treated red claw crayfish exhibited very distinctive or substantial differences compared with fresh individuals.