Storage stability of frozen red hake blocks over a 6-month period was studied under commercial conditions with processing modifications. The rate of DMA formation was significantly greater in samples dipped in polyphosphate and erythorbate compared to a reference (-90°C) or to a 5-day aged sample. There were no significant differences in the rate of decrease of extractable protein nitrogen over the 24-week period. A trained sensory panel found samples from aged fish to be generally more acceptable from a flavor and texture stand-point than the other treated samples. Mechanical shear forces tended to be higher for samples dipped in polyphosphateerythorbate and lowest for 5-day samples among treated fiiets. With proper handling red hake fiiets may make a satisfactory commercial frozen block.

Frozen storage life of red hake fillet blocks was estimated b y sensory evaluation to be 150 weeks at -20" F, 71 weeks at -5" F, 25 weeks at +5" F, 7.5 weeks at +lo" F u n d 2.7 weeks at +20" F. Shelf life was limited b y the development of a tough, fibrous texture and the reaction proceeded a t a faster rate a t temperatures above +5" F. Dimethylamine content, formaldehyde content and shear force measurement correlated very well with sensory texture score and thus, these objective tests could be useful for predicting textural quality. For product stored at temperatures above -5" F there was good correlation between extractable protein nitrogen and sensory texture score, but this correlation decreased with lower storage tempratures. Trimethylamine oxide content and p H diminished during the early phase o f storage and then progressively increased during continued storage. Centrifuged drip as a n objective quality test did not appear to be sufficiently sensitive or reliable for assessing textural quality.

Irradiation of cod fillets with a maximum absorbed dose of 100 Krad extended iced storage life by about 9 days. Further extension of several days resulted when irradiation was combined concurrently with either 60% CO:! packaging atmosphere or sorbate additive. Packaging at low oxygen tension did not provide any additional benefit for irradiated fish. No important difference ln storaae life of treated fish was observed due to-one vs three day postmortem age. The 100 Krad treatment extended grade B quality market life as opposed to grade A (prime quality) market life, Certain physical/ chemical tests were evaluated for their efficacy in estimating spoilage. Concentrations of TMA, DMA, hypoxanthine, APC and pH at spoilage were comparable in control and air-irradiated samples, but were less in sorbate-irradiated fillets.