vet inspection of fish

Question 1

fish products - health standard (7)

Answer 1

1. sensory tests (randomly + market)
2. indicators of freshness
3. histamine (randomised)
4. residues and contaminants - monotirng
5. microbiological testing- when necessary
6. parasites - random before placing on market
7. toxic fishery products

Question 2

sensory changes

Answer 2

• changes in raw and fresh fish - appearance, consistency, smell, taste, rigot
• may depend on storage and species

Question 3

degradation of fish stored in ice

Answer 3

phase 1
- fish is fresh (smell, taste and slightly metallic)
phase 2
- loss of smell and taste
phase 3
- signs of spoilage (unpleasant odour) very “fishy” smell
phase 4
- characterised as spoiled

Question 4

sensory analysis

Answer 4

distinguish test
- triangle test = whether’s there’s differences between 2 samples
- “ranking” classify large number of samples

descriptive test
- quality index method - sensory indicators of fish freshness (0-3 points)

sensory test - “market test”

Question 5

slow stunning method

Answer 5

• icing = immersed in cold water, after 10 mins they stop moving
• bleeding = gills cut, returned back to water to bleed
• evisceration = without stunning
• decapitation = for eels
• CO2 = at least 4.5 mins, then bleed
• electro immobilisation

Question 6

fast stunning methods

Answer 6

• percussive stunning = in salmon
• electrical stunning
• hydraulic shock = use of explosive
• wedge killing = piercing skull and brain

Question 7

opisthorchis felineus

Answer 7

• liver parasite (fluke)
• intermediaries = freshwater snail and fish
• human invasion = by eating fish
• asymptomatic, vomiting jaundice, anaemia etc

Question 8

life cycle of O. felineus

Answer 8

snail eats egg (miracidium)
miracidium goes to cercariae in the water
cercariae eaten by fish
goes to muslce
and developed to metacercariae

Question 9

heterophydae

Answer 9

• intestinal fluke of human and other vertebrates
• same as O. felines life cycle
• human invasion = undercooked/raw fish
• signs = chronic diarrhoea, colic, vomit

Question 10

diphylobothrium latum

Answer 10

• tapeworm
• parasitises in SI of humans, dogs, cats, pig, bear
• 2 intermediaries = paddlers + freshwater fish
• mostly asymptomatic

Question 11

life cycle of d. latum

Answer 11

egg in wter
coracidium hatches
eaten by shrimp
proceroid develops
fish eats shrimp
prerocercoid
something eats fish

Question 12

nematodes

Answer 12

angiostrongylus (causes oesonophilic enteritis)

capillary (human intestinal capillaria)

anisakis (eosinophilic phlegmonous enteritis)

Question 13

larva isolatio

Answer 13

UV radiation - UV lamp - preliminary identification
- anisaki and pseudoterranova = light blue to white
- contracaecum - yellow colour

elution - extraction of larva from muscle with saline solution

digestion = 200g of fish muscle and 750ml of pepsin solution

Question 14

anisaki larvae in fish muscle killed by

Answer 14

heat treatment 60oC/30 min
freezing 20oC/ 60hrs
brining - 20Be/10 days

Question 15

recommendation for anisaki

Answer 15

evisceration of fish immediately after catch
if necessary remove abdominal part of muscle

Question 16

myxosporea

Answer 16

• parasites on gills, urinary and gall bladder and muscle
• not dangerous to humans
• cause organoleptic changes
• kudoa spp, henneguya schokkei, hhengyuya salminicola
• causes changes in muscle, cysts
• henneguya differs in caudal extension of spores

Question 17

Copepoda - sphyrion lumpi

Answer 17

• ectoparasite
• mostly scorpion fish
• organoleptic changes I n muscle
• tissue reaction = brown to grey solid cyst, unpleasant odour