Effect of Brining, Modified Atmosphere Packaging, and Superchilling on the Shelf Life of Cod (Gadus morhua) Loins

Abstract

The aim of these experiments was to evaluate the effect of brining, modified atmosphere packaging (MAP), and superchilling on the quality changes of cod loins as measured by microbial, sensory, and chemical analysis. Unbrined and brined (2.5 +/- 1.0% NaCl) cod loins were kept in styrofoam boxes (air) and under modified atmosphere (MA, CO(2)/O(2)/N(2): 50/5/45) at 0, -2, and -3.6 degrees C. Samples were examined over a 4-wk period. Total viable psychrotrophic counts and counts of H(2)S-producing bacteria reached higher numbers in the air-packed brined fish at -2 and -3.6 degrees C than in comparable unbrined groups, being significantly different (P < 0.05) at the lower temperature. However, lower counts of these bacteria were obtained in the brined MAP fish than in comparable unbrined fish. Counts of Photobacterium phosphoreum increased most rapidly in air- and MA-packed loins kept at 0 degrees C. Lower counts were found at superchilled temperatures. According to sensory analysis the shelf life of unbrined air-packed loins was about 11 d at 0 degrees C and 14 to 15 d at -2 degrees C. The shelf life of MA-packed unbrined loins was about 14 to 15 d at 0 degrees C but 21 d at -2 degrees C. Thus, synergism of combined superchilling (-2 degrees C) and MA led to a considerable shelf life increase for unbrined loins despite the fact that processing and packaging took place 4 to 5 d post-catch. The shelf life of air-packed brined loins at -2 degrees C was 12 to 15 d but only 13 d under MA. The same synergistic effect did therefore not apply to brined loins as with unbrined ones.

Effect of vacuum or modified atmosphere packaging (MAP) in combination with a CO 2 emitter on quality parameters of cod loins ( Gadus morhua )

“…It is well documented that P. phosphoreum is associated with colonization of MAP fish (cod, salmon, coalfish) (Reynisson et al, 2009;Hansen, Mørkøre, Rudi, Rødbotten et al, 2009;Rudi, Maugesten, Hannevik & Nissen, 2004;Debevere & Boskou, 1996;Mejlholm & Dalgaard, 2002;Dalgaard, Munoz & Mejlholm, 1998), but also detected when stored in air (Lauzon, Magnusson, Sveinsdottir, Gudjonsdottir & Martinsdottir, 2009). In the presented study, characterization of bacteria based on the highthroughput sequence analyses of the 16S rRNA gene, performed directly from the fish matrix, showed that bacteria belonging to the Photobacterium group dominated both after 9 and 13 days of storage for all packaging methods.…”

Continuous quality and shelf life monitoring of retail-packed fresh cod loins in comparison with conventional methods

“…For chilled trays (TT) two different charging levels of SVo 61 and 60 were investigated, which corresponded to the TTI lifespan of 100 and 136 h at 0.5 C (Mai et al, in press). These charging levels were chosen based on the expected shelf life of air packed cod loins at 0.5 C of about 10e12 days (or 4e6 days from repackaging done on day 6 after processing) (Lauzon et al, 2009;Olafsdottir, Lauzon, Martinsdottir, Oehlenschlager, et al, 2006) and the lifespan of the TTI in dependency with SVo at the same temperature (Mai et al, in press). Charged TTI labels were stuck on the white labels both on top and bottom surfaces of packed trays using 3 labels per charging time, resulting in 3 (ST case) or 6 labels (TT case) on each pack side.…”

“…For superchilled trays (ST), a charging level of an initial square value SVo 59, as defined in Eq. (1), corresponding to a charging time of 650 ms at ambient conditions of 7 C and RH 60%,was used, based on a previous study of the TTI lifespan (Mai et al, in press) and the shelf life of cod loins at À1 C (Lauzon, Magnússon, Sveinsdóttir, Gudjónsdóttir, & Martinsdóttir, 2009;Olafsdottir, Lauzon, Martinsdottir, Oehlenschlager, & Kristbergsson, 2006), which was expected to be around 15 days (repacked on day 0). For chilled trays (TT) two different charging levels of SVo 61 and 60 were investigated, which corresponded to the TTI lifespan of 100 and 136 h at 0.5 C (Mai et al, in press).…”

Low field Nuclear Magnetic Resonance on the effect of salt and modified atmosphere packaging on cod (Gadus morhua) during superchilled storage

“…Optimization of chilling techniques and physiochemical properties of the fish is therefore crucial to ensure good quality of fish products to the consumers. Furthermore, the fish becomes microbiologically more stable as the temperature is lowered (Andersen, Jul, & Riemann, 1965;Huss, 1995;Lauzon, Magnússon, Sveinsdóttir, Gudjónsdóttir, & Martinsdóttir, 2009). To ensure optimal quality of fresh fish it is important that no water in the muscle freezes during storage, since freezing is known to cause aggregation and destruction of muscle proteins (Love, 1968;Sikorski, Olley, & Kostuch, 1976).…”