composition and quality of fish, crabs and shellfish

Question 1

PM changes in fish

Answer 1

• sensory (organoleptic) changes
• bacterial degradation, fato oxidation and hydrolysis

1. phase of enhanced mucus secretion (after death increases, cloudy opaque and MO develop)
2. phase of rigor mortis (stop mucus secrertion to prolong stage, decrease temp)
3. phase of autolysis (decomposition of meat)
4. bacterial decomposition (complete spoilage and microbiological degradation)

Question 2

histamine in fish (scombrotoxin)

Answer 2

• histamine posioning
• after consuming fish insufficiently/improperly chilled after catch
• enterobacteria
• prevention -> rapid cooling of fish after catch
• toxin is thermostable
• without signs

Question 3

virus contamination of shellfish

Answer 3

• shell fish caught from waters near the shore
• animal/human faeces
• enteroviruses associated with consumption of seafood
• heat treatment (85-90oC/1.5min) destroys virus in shellfish

Question 4

preventi transmission of disease from shellfish to humans

Answer 4

1. boil mussels thoroughly after shell has been open
2. cook them for another 5 mins
3. don’t throw/eat shellfish that haven’t opened
4. wear gloves