Use of high pressure processing in combination with acidic electrolyzed water depuration for the shelf-life extension of blood clam (Tegillarca granosa)

The combined effects of acidic electrolyzed water (AEW) depuration and high pressure processing (HP-P) on reduction of growth of spoilage bacteria and pathogens in blood clams (Tegillarca granosa) during cold storage were investigated. After HP-P treatment of depurated blood clams at 300 MPa for 3 min (HD-300), total viable count (TVC), psychrophilic bacteria count (PBC), presumptive Gram-negative, Vibrio parahaemolyticus, lactic acid bacteria, and Pseudomonas spp. in blood clams were completely inactivated at day 0. TVC of HD-300 was lower than the limit (6 log(10) CFU/g) up to day 9, while untreated sample could be kept less than 3 days. HD-300 clam sample also showed the higher expansion rate and shucking ratio. In addition, lower reductions in heme iron content, a* value (redness), moisture content and texture properties were observed in HD-300. This coincided with lower total volatile basic nitrogen content, fatty acid oxidation than other samples (p < 0.05). Based on histological study, intestine, mid gut gland, gonad, and gill were moderately disrupted in HD-300. Overall, AEW depurated blood clam in combination with HP-P (300 MPa, 3 min) effectively reduced TVB-N formation, maintained the heme iron content, and prolonged the shelf-life of blood clam for 9 days at 4 degrees C.