Objective spoilage tests for fish stored under conditions other than normal chilling in ice

Abstract

Cod fillets were stored at various temperatures between -2' and +4" c without ice and subsequently subjected to organoleptic grading and several objective deterioration tests. The determination of trimethylarnine-nitrogen gave a constant value for the threshold of acceptability with sufficient accuracy. Bacterial counts and the determination of ammonia-nitrogen, volatile acid and tyrosine did not meet the relevant requirements. None of these determinations proved satisfactory as an objective deterioration test for thawed, quick-frozen fish.The onset of rigor mortis in the longissimus dorsi muscle of the lamb has been studied. with particular emphasis on the effect of temperature on its time-course. With the introduction of faster-freezing techniques in the frozen lamb industry, part of the carcass may be frozen before the onset of rigov mortis. It is shown, however, that the extreme shortening and loss of ' drip ' characteristic of thaw rigor in isolated muscles w i l l not occur if the muscles remain attached t o the skeleton and thawing is not accelerated.

Determination of Different Volatile Base Components as Quality Control Indices in Fish by Official Methods and Flow Injection Analysis

“…It is clearly indicated there that the samples prepared from frozen fish (sprat and king scallop) which were later thawed and stored on ice, showed much lower levels of TMA-N compared to fresh cod stored on ice. This is in agreement with other authors (Luijpen 1958;MagnGsson and Martinsddttir 1995), who showed that the formation of TMA-N in thawed fish, subsequently stored in ice, proceeded at a slower rate than in fresh fish. The initial level of TMA-N in sprat was greater than for the other species (Fig.…”

“…The high TVB-N figures for sprat at the end of the storage trial is a reflection of the advanced stage of bacterial spoilage reached by this species after 16 days compared with the other species, particularly after being frozen and thawed. Magnusson and Martinsdottir (1995) also found an increase in the levels of TVB-N in frozen-thawed fish after 13 days of storage in ice in comparison to fresh fish stored in ice. Freezing and thawing sprat prior to iced storage, therefore, appears to make the product susceptible to more rapid spoilage towards the end of its shelf-life.…”

Storage Quality of Fresh and Frozen‐thawed Fish in Ice

“…Relatively few reports have been published on the storage quality of thawed fish in comparison to fresh (unfrozen) fish in ice. Experiments done by Luijpen (1958) on cod fillets with skin kept at different temperatures showed that TMA was produced slower in thawed fillets than in unfrozen ones. Those results were not in accordance with sensory analysis and not explained by differences in bacterial counts.…”

QUALITY OF FROZEN/THAWED SPRAT (SPRATTUS SPRATTUS SPRATTUS) STORED IN CLING FILM AND ALUMINUM FOIL AT 4C1

“…Nevertheless, differences in rate of deterioration between the AF and CF lots were inconclusive overall. The lack of coincidence of the limit of fitness for human consumption as determined using the biochemical parameters (TMA-N and TVB-N) determinations compared with that determined using sensory assessment has also been noticed by other authors (Vyncke 1983;Luijpen 1958) using frozedthawed cod fillets. Means in each column with the same letter for independent parameten indicates no significant differences (P<O.OS)…”