Classes and Qualities of Fish and Seafood Food Technology

Classifications of Fish and Seafood: oThere are different methods used to classify fish and seafood including: oMuscle texture oEdibility characteristics oCartilaginous vs. bony oFresh vs. Saltwater oMigratory habits oAnatomy

Finfish or Shellfish? oIdentified by: oBody shape oNumber of spines and rays in fins oNumber and type of scales and teeth oEye diameter oInternal anatomy oLocation of specific body parts

Why should you not identify by color? oColor changes due to: oStress oBeing hooked oBeing removed from the water oEnvironmental changes oSpawning (trout and salmon)

Finfish: 2 Types 1.Cartilaginous oSharks, Rays oSkeletons made of cartilage rather than bone

Finfish: 2. Bony o95% of all known fish species oCatfish, bass, trout, salmon, perch, tuna, snapper, grouper

Finfish oVary in size, shape, color and other physical characteristics oAll share certain physical features

Overall Structure of Finfish:

Shellfish oInvertebrate = NO backbone! oMust have an external skeleton in the form of a calcareous shell oMollusks and arthropods

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

Arthropods: oShrimp, lobster, crab and crawfish

Chart it Out!

Quality of Fish: Check it Out! o3 Determinants: oAppearance oTexture oOdor!!!!

Fresh Fish Qualities: oEyes: oBright, clear and full oAs fish becomes stale, eyes become cloudy and sunken oGills: oRed and free from slime oGill color fades with age from pink to gray, brown and then green

Fresh Fish Qualities: oOdor: oFresh and mild oAs age increases, a strong, offensive odor develops oSkin: oShiny with bright colors oAs fish ages, skin colors fade and become less pronounced

Fresh Fish Qualities oFlesh: oFirm, elastic and not separating from the bones oAs fish ages, flesh changes colors and takes on a dried out appearance

Shellfish Qualities: oLobsters and Crabs oHeavy for size and show leg movement oTail of live lobster curls under body and doesn’t hang down when picked up

Shellfish Qualities: oOysters and Clams oHard, well cupped shells oGaping shell indicates the shellfish is dead and is no longer edible oShells are graded as fancy, choice, standard, and commercial

Indications of Poor Quality: oVoids oDehydration oDiscoloration oRancidity (indicated by orange color) oDeterioration in shrimp (soft, mushy) oBlack spot

Controlling Quality: oQuality determined by: oSpecies oMethod of catching oHandling oProcessing oDoes the consumer have control over these factors?

oChemical changes oEnzymes remain active resulting in spoilage and flavor changes oOccur during the first few days of cold storage before bacterial spoilage begins

oOxidative Rancidity oFat content increases rancidity oAffects taste and aroma oBacterial spoilage oSurface slime, intestines, and gills harbor bacteria oWhen fish dies, loses defense against bacteria

Review: oClassifications of seafood and fish oQuality characteristics oReasons for spoilage