Seafood: Fish and Shellfish

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Seafood Fish and Shellfish

• I. Issues related to seafood consumption
• II. Classification
• III. Composition and structure
• IV. Seafood freshness

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Issues Nutrition

• Low fat contents
• Highly unsaturated fat
• Omega-3 Fatty Acids
• Good source of protein
• Mineral content

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Issues Seafood Attributes

• Ideational
• source (murky waters)
• habitat (diet)
• Sensory
• Aroma
• Flavor
• Texture

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Issues Production

• Where are fish found?
• New developments in fishing technology
• Over-fishing/harvesting of the oceans
• Aqua-culture on the rise

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Chesapeake Bay
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Beach Closings
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Reefs Around the World

• Bleaching

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Lobsters--State of the Industry

• Sudden drop in population

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Classification
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Finfish

• Groundfish
• Pelagic
• Reef

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Reef-fish
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Groundfish
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Mollusks Bivalves

• Oysters Belon, Pacific, Malpeque
• Mussels green and blue
• Scallops bay, sea, calico
• Clams
• Cherrystone
• Littleneck
• Quahog/chowder
• Surf clams
• Soft shell
• Geoduck

Hard shell clams
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Mollusks
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Bivalves Calico Scallops
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Crustaceans

• Lobster
• American
• Rock-lobster warm water/cold water tails
• Crab
• Blue hard/soft shell
• Snow
• King
• Shrimp
• Tiger, pink, white
• Crayfish

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Crustaceans King Crab
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Crustacean Bluecrab
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Danish/Icelandic Lobster (Scampi)
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Cephalopod Squid
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Seafood DistributionTuna Auction
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Seafood Distribution Fresh Tuna
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Seafood Utilization Sashimi quality tuna
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Fresh eel
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Live Fish Market Tsukiji
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Live Fish
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X-Ray of Flounder
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Seafood composition

• Why is fish meat white and why does it flake?
• Why does lobster change its color from greenish
  brown to red after it is cooked?
• Why does fish require a shorter cooking time
  (compared to meats)?

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Structure of Fish Muscle
myotomes
myotoma
myocommata
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White and dark muscles
mitochondria
nucleus
capillaries
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White vs. dark meat
Cod
Mackerel
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swordfish
dark muscle
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Shark
dark muscle
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Lobster pigments
uncooked lobster astaxanthin complexed with
protein
cooked lobster protein complex
denatured astaxanthin released
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Aqua farming Salmon
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Aqua farming collecting eggs
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Freshness of seafood
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Freshness characteristics

• Odor fresh ocean most important indicator
• Gills bright red (hemoglobin color)
• red pink light -dark gray
• Texture firm flesh springs back
• Eyes clear bulging, not sunken
• Scales clingy

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Temperature Dependence of Spoilage
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Stages in Fish SpoilageStages Tissue Changes
Organoleptic Changes Bacterial Count

• Stage 1 rigor mortis eyes bright, flesh firm 102
  -103/ 0 - 5 changes in good color, gills
  bright cm2 days in bacterial fresh odor
  ice types
• Stage 2 bacterial eyes begin to dull 103 - 106/
  5 - 10 growth gill color fades
  cm days in becomes skin color
  fades ice apparent texture
  softens NH3 incr. odor slightly fishy
• Stage 3 rapid eyes sunken, gills 106 - 108/
  10 - 14 bacterial discolored and cm2
  days in growth skin color fades ice
  penetrate. soft texture of tissue odor
  sour and incr. NH3 fishy,
  rancid uric acid

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Stages in Fish SpoilageStages Tissue Changes
Organoleptic Changes Bacterial Count

• Stage 4 bacterial number eyes opaque and
  gt 108 / cm2 over stationary sunken
  14 days proteolysis gills brown and
  in ice general slimy, skin very
  slimy deterioration texture very
  soft NH3, H2S and odor offensive
  products formed

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Storage and Handling

• keep whole fish in ice
• always store fish away from dripping juices, i.e.
  in perforated pan with dripping pan
• regularly change ice
• FIFO inventory method
• lift whole fish carefully
• always follow sanitation rules

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Fugu a meal for daring guests