Comparative Quality Loss in Wild and Cultured Rainbow Trout (Oncorhynchus mykiss) during Chilling Storage

Abstract

The aim of this study was to determine and compare differences in sensory, chemical and microbiological post-mortem changes between wild and farmed rainbow trout (Oncorhynchus mykiss). Lipid content was higher (5.77%) in wild fish than cultured fish (3.02%). Wild fish were very rich in n-3 fatty acids. Although wild fish were preferred to cultured fish due to the taste and flavour, shelf life of both wild and cultured rainbow trout was 14 days with demerit scores of 16 and 14, respectively. Chemical analyses showed that lipid oxidation and hydrolysis developed at a higher rate in wild rainbow trout. Histamine was not detected in any samples throughout the storage period apart from wild rainbow trout at 7 days of storage. Initial total viable counts (TVC) of fish was 3.59 log CFU/g for cultured rainbow trout and 3.36 log CFU/g for wild rainbow trout, which showed high quality of fish. Coliform and E. coli were not detected for both groups. When fish were unacceptable at the days of 14, TVC content was 6.16 log CFU/g for wild rainbow trout and 6.35 log CFU/g for cultured rainbow trout.

A practical quality index method (QIM) developed for aquacultured rainbow trout (Oncorhynchus mykiss)

“…Wunnenberg and Oehlenscläger [33] reported the shelf life of rainbow trout that are stored on ice on autumn for 14 days and on winter, spring, and summer for 16 days. Ninan et al [34] found the shelf life of whole rainbow trout in accordance with the sensory results for 12-14 days while Özoğul et al [35] found similar shelf life, namely, 14 days for whole wild and aquacultered rainbow trout. In addition, Chytiri et al [36] reported 15-16 days in whole rainbow trout on ice and 10-12 days shelf life for fillet.…”

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“…In cultured fish, the ω3 PUFA is generally lower than that of wild fish because of possibly the lack of lipids originating from phytoplankton and aquatic organisms in cultured diets (Ackman & Takeuchi, 1986). Similarly, Ozogul et al (2013) stated that wild fish had much higher ω3 fatty acids than their cultured ones. This situation could result from the feed.…”

“…Another important factor affecting fatty acid composition is whether the fish is wild or cultured. Wild fish contain more ω3 fatty acids than cultured fish (Ozogul, Yavuzer, Ozogul, & Kuley, 2013). In addition, wild fish living in lakes are better sources of DHA than cultured fish reared in polyculture (Łuczyńska, Tońska, Krejszeff, & Żarski, 2016).…”

Sensory quality and consumers’ acceptance towards wild and farmed brown-trout (Salmo trutta) and farmed rainbow-trout (Oncorhynchus mykiss)

“…Without using the internal preference map approach, Pohar (2011) observed that the panel created by his team had a slight preference for farmed brown trout. Ozogul et al (2013) verified that consumers preferred wild rainbow trout. These discrepancies found among different research results might be related with both with fish intrinsic and extrinsic features (geographical origin, genotype, season, sexual maturation, age, feeding, water quality, presence of disease and parasites), which influence fish chemical composition and, consequently, fish sensory variables (taste, texture, and appearance) which, in turn, determine fish quality, consumer acceptance and commercialization (Grigorakis, 2007;Green-Petersen & Hyldig, 2010;Oken et al, 2012;Claret et al, 2014;Suomela et al, 2016).…”