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

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

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

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

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

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)

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

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

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

Overall Structure of Finfish:

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

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

Arthropods: Shrimp, lobster, crab and crawfish

Chart it Out!

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

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

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

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

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

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

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

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

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

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

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!

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