1. Classes and Qualities of Fish and Seafood
Something’s Fishy…
Classes and Qualities of Fish and Seafood
Food Technology
From foukeffa.org
Written by Liz Rogers
Ag Student Texas A&M
GA Ag Ed Curriculum Office
To accompany the Georgia Agriculture Education Curriculum Lesson 03431
July 2001

2. Today’s Objectives: Identify the classifications of fish and seafood
Identify the quality determinants in fish and seafood and their importance
Here Fishy, Fishy Activity

3. Classifications of Fish and Seafood:
There are different methods used to classify fish and seafood including:
Muscle texture
Edibility characteristics
Cartilaginous vs. bony
Fresh vs. Saltwater
Migratory habits
Anatomy

4. Fish: Two Types of ‘em!
How did the people know that Jaws was coming to get them?

5. Finfish or Shellfish? Identified by: Body shape
Number of spines and rays in fins
Number and type of scales and teeth
Eye diameter
Internal anatomy
Location of specific body parts

6. Why should you not identify by color?
Color changes due to:
Stress
Being hooked
Being removed from the water
Environmental changes
Spawning (trout and salmon)

7. Finfish: 2 Types Cartilaginous Sharks, Rays
Skeletons made of cartilage rather than bone

8. Finfish: 2. Bony 95% of all known fish species
Catfish, bass, trout, salmon, perch, tuna, snapper, grouper

9. Finfish Vary in size, shape, color and other physical characteristics
All share certain physical features

10. Overall Structure of Finfish:

11. Shellfish Invertebrate = NO backbone!
Must have an external skeleton in the form of a calcareous shell
Mollusks and arthropods

12. Mollusks:
Clams, oysters, mussels, scallops,whelks, squid and octopus

13. Arthropods:
Shrimp, lobster, crab and crawfish

14. Chart it Out!

15. Quality of Fish: Check it Out!
3 Determinants:
Appearance
Texture
Odor!!!!

16. Fresh Fish Qualities: Eyes: Gills: Bright, clear and full
As fish becomes stale, eyes become cloudy and sunken
Gills:
Red and free from slime
Gill color fades with age from pink to gray, brown and then green

17. Fresh Fish Qualities: Odor: Skin: Fresh and mild
As age increases, a strong, offensive odor develops
Skin:
Shiny with bright colors
As fish ages, skin colors fade and become less pronounced

18. Fresh Fish Qualities Flesh:
Firm, elastic and not separating from the bones
As fish ages, flesh changes colors and takes on a dried out appearance

19. Shellfish Qualities: Lobsters and Crabs
Heavy for size and show leg movement
Tail of live lobster curls under body and doesn’t hang down when picked up

20. Shellfish Qualities: Oysters and Clams Hard, well cupped shells
Gaping shell indicates the shellfish is dead and is no longer edible
Shells are graded as fancy, choice, standard, and commercial

21. Indications of Poor Quality:
Voids
Dehydration
Discoloration
Rancidity (indicated by orange color)
Deterioration in shrimp (soft, mushy)
Black spot

22. Controlling Quality: Quality determined by:
Species
Method of catching
Handling
Processing
Does the consumer have control over these factors?

23. What the Heck Happened? Chemical changes
Enzymes remain active resulting in spoilage and flavor changes
Occur during the first few days of cold storage before bacterial spoilage begins

24. What the Heck Happened? Oxidative Rancidity Bacterial spoilage
Fat content increases rancidity
Affects taste and aroma
Bacterial spoilage
Surface slime, intestines, and gills harbor bacteria
When fish dies, loses defense against bacteria

25. Here Fishy, Fishy!
Match the given seafood or fish cut out with the proper classification and then determine whether it is of low or high quality. Explain your answer!

26. Review: Classifications of seafood and fish Quality characteristics
Reasons for spoilage