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Research Project: Development of Management Strategies to Mitigate Pre-harvest Microbial-derived Off-flavors in Fish Grown in Aquaculture

Location: Natural Products Utilization Research

Title: Fillet and product quality research at the Freshwater Institute: Off-flavor remediation, harvest techniques, and humane slaughter

item DAVIDSON, JOHN - Freshwater Institute
item SUMMERFELT, STEVE - Freshwater Institute
item MAY, TRAVIS - Freshwater Institute
item CROUSE, CURTIS - Freshwater Institute
item KENNY, BRETT - West Virginia University
item Cleveland, Beth
item Schrader, Kevin
item TSUI, ANDREW - Ike Jime Federation, Llc
item GOOD, CHRISTOPHER - Leibniz Institute Of Freshwater Ecology And Inland Fisheries

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/28/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: At our RAS facilities, extensive effort is devoted to maintaining culture conditions that support optimal fish health, growth, and survival; however, optimizing the finishing steps that influence food quality of market-ready fish is also critical. Standard operating procedures for off-flavor remediation, low-stress harvest techniques, and humane slaughter practices must be utilized to create an end-product with organoleptic properties that meet consumer expectations. As part of a holistic approach to RAS-based research, The Conservation Fund’s Freshwater Institute is developing and implementing end-of-cycle procedures that enhance salmonid fillet and product quality attributes, while maintaining optimal fish welfare. Past research will be summarized, and additional unpublished data will be presented pertaining to these topics. The occurrence of off-flavors in RAS-produced finfish continues to be detrimental to this industry sector. Common off-flavors, geosmin and 2-methylisoborneol contribute earthy or musty tastes, respectively, which results in consumer dissatisfaction and negative perception of RAS-produced products. A 2x2 factorial trial was carried out to evaluate off-flavor removal kinetics in partial reuse systems either containing or void of water aeration media and with and without pre-disinfection using a hydrogen peroxide solution. Facility-specific depuration protocols that consistently result in clean-tasting fillets were adopted based on this research. Recent research evaluated the effects of pre-slaughter crowding densities (100, 200, and 300 kg/m3) on plasma chemistry and post-slaughter product quality metrics of Atlantic salmon fillets. Atlantic salmon adapted to increasing biomass density by resting near the tank bottom. Short-term crowding of Atlantic salmon prior to slaughter did not result in increased stress or negative effects to product quality attributes. Utilizing humane slaughter techniques is critical for product quality optimization and maintenance of proper fish welfare standards. Onsite research has demonstrated that a pneumatic stunning system (SI-7, Baader Group, Germany) results in humane fish slaughter and extended rigor mortis onset compared to euthanasia with a carbon dioxide/ice slurry which induces fish struggle, lactic acid build-up (reduced pH), and accelerated rigor onset. During a subsequent trial undertaken with staff from the Ike Jime Federation, the SI-7 stunning method resulted in comparable rigor onset and product quality outcomes similar to those achieved using ike jime, a Japanese slaughter/handling technique designed to optimize the eating quality of certain finfish.