Theme 7: Seafood Technology Flashcards
What is spoilage?
Spoilage occurs as a series of complex bacterial, enzymatic and chemical changes that begin as soon as the fish is caught.
What are the main two agents of spoilage?
Bacteria and enzymes
Where is bacteria normally found on the fish? and what is it called?
It is usually found on the surface of the fish(skin)(slime), gills and gut. The are called resident flora.
What keeps the bacterial numbers down when the fish is alive?
Its natural defenses like anti-bacterial substances in the mucus and the continual sloughing of the mucus.
What are the favorable conditions for bacterial growth
temperature oxygen pH salinity water nutrients
What are enzymes?
Enzymes are proteins found in all the cells of the body
They act as organic catalysts that speed up chemical reactions
Enzymes in the gut help to beak down food
What us bacteria?
Bacteria are microscopic unicellular organisms
How does enzymes work to control growth? And what would happen if the temperature is too low and too high?
It works within a relatively narrow temperature range.
If the temperature falls too low, the rate of enzyme-catalyzed reaction becomes too slow to sustain growth.
If its too high, the break-up of enzymes cause death.
What is rigor mortis?
The stiffening of muscles of an animal soon after death
What are the stages of rigor mortis?
Pre-rigor
Rigor
Post-rigor
What is pre-rigor? How long does it last? and why?
It is the stage when the fish muscle is still soft immediately after death.
It lasts anywhere from an hour to a few days.
Because of continued enzymatic activity.
What is rigor? How long does it last?
It is the stage when the fish muscles goes very hard or stiff.
This stage can last up to as long as 7 days
in well tropical iced fish
What is post-rigor?
It is the stage when the fish muscles softens again and becomes limp
At what stage does spoilage begins at?
Post-rigor
What are the effects rigor can have on frozen fish?
Gaping
Toughening
Drip loss
Shrinkage
