Exporting live shellfish products while ensuring their quality and safety on arrival presents significant challenges. As surface transport times from Australasia to major export markets are prohibitively long air freight has so far been the only viable option. This is becoming increasingly costly and generates a significant carbon footprint. For surface shipping to be viable, more effective preservation of the ‘as-harvested’ shellfish properties is needed. To progress this aim, we evaluated the effects of chilled storage (6.5°C) in air, refrigerated seawater recirculated either continuously (RSW), or for 6 min per hour (Periodic RSW), on Greenshell™ mussel (GSM) post-harvest performance (i.e., physiology, product quality and food safety) for 10 days in two trials conducted in austral spring (October 2020) and summer (March 2021).
GSM interacted with seawater at 6.5°C, even when delivered periodically, as ammonia seawater concentrations increased. Mortalities across both 10-day trials were 5.5% for Chilled, 3.5% for RSW, and 2.4% for Periodic RSW. Haemolymph pH and intravalvular water weight were good measures of performance. Reduced haemolymph pH was seen in the Chilled and Periodic RSW GSM from day 2 through to day 10, and higher variance could be seen on days 4 and 10 in the summer trial. Intravalvular water weights were stable in the spring trial in all three treatments, but were lower and showed increased variance in the Chilled and Periodic RSW treaments in summer. Meat textural hardness was best preserved by RSW. For GSM inoculated with Escherichia coli and Vibrio parahaemolyticus, most probable numbers (MPN) were stable for the Chilled and Periodic RSW treatments, with reductions in MPN seen in RSW on days 7 and 10. Post-harvest seawater treatments for GSM show potential and further optimizations are plausible. We also highlight GSM condition at harvest as a factor influencing post-harvest storage outcomes.