Seafood Hygiene & Inspection Flashcards
What are the 2 categories of seafood?
- FISH - carp, tilapia, catfish, salmon, trout
- SHELLFISH - shrimp, prawn, crab, lobster, freshwater crustaceans
What are the 2 divisions of commercial shellfish?
- CRUSTACEANS (have jointed legs) - lobsters, crabs, shrimps, prawns
- MOLLUSKS (filter feeders) - clams, mussels, scallops, oysters
What is considered fish according to US legislation?
fresh or saltwater fish, crustaceans, and other forms of aquatic animal life including alligators, frogs, turtles, jellyfish, sea cucumbers, sea urchins, and mollusks
What is the anatomy of fish muscle like? How does this affect contamination?
contain little connective tissue and have high levels of water (> 80%)
supports bacterial growth and movement with rapid microbiological deteriorations —> short shelf life, must be stored at lower temperatures (0 C)
What 2 components are high in fish tissue? What is the pH like?
- non-protein nitrogenous compounds
- peptides
> 6.0 because it has low glycogen and lactic acid (high bacteria!)
What non-protein nitrogenous compounds are found in fish tissue?
- free amino acid (less work for bacteria): histidine
- volatile nitrogen bases: ammonia, trimethyl amine
- creatinine
- taurine
- uric acid
- anserine
- carnosine
What are the 4 steps in the seafood supply chain? Why is it so short?
- production
- processing
- wholesale distribution
- retail sales
fish spoils much faster than other meats
Where does food production occur? When are they slaughtered?
waterbodies —> fisheries
2 years old (small adults)
What are the 2 types of fish based on the type of aquaculture used?
- freshwater: lakes, rivers, ponds, manmade system —> catfish, trout
- saltwater: sea, ocean —> shellfish (oysters, clams, mussels, shrimp, seaweeds), salmon, black sea bass, sablefish, yellowtail, pompano
What do biosecurity and GHP center around in the fish industry? What are the 5 pillars of animal welfare?
waterbodies —> protect water from sources of biological and chemical contamination of fish
- feed
- water
- health
- space
- avoid fear and allow normal social behavior
What enteric viruses typically affect fish?
- Norovirus
- Hepatitis virus
- Sapporovirus
- Astrovirus
- Rotavirus
- Adenovirus
What aquatic commensal, environmental, and enteric bacteria typically affect fish?
COMMENSAL - Aeromonas, Pseudomonas, Vibrio, Clostridium botulinum, Erysipellothricx, Pasteurella, Edwardsiella, Mycobacterium marinum
ENVIRONMENTAL - Clostridium perfringens, Bacullus, Listeria monocytogenes (soil or decay)
ENTERIC - Salmonella, Shigella, E. coli, Campylobacter jejuni, Staph. aureus (sewage)
What nematode, cestode, trematode, and protozoa typically affect fish?
NEMATODE - Anasakkis
CESTODE - Diphyllobuthrium
TREMATODES - Clonorichis, Opistorchis
PROTOZOA - Giardia, Cryptosporidium
What is the processing line at fish slaughterhouses like?
- shipping
- stunning
- bleeding
- shucking
- gutting
- washing
- grading
- packing
- delivery
What is a necessary step before the slaughter of fish? Why? What happens next?
fast/starvation for 1-3 days - reduces the amount of feces in the intestines and delays spoilage
remove 5D fish —> slaughter only healthy fish
What are 5 ways that fish can be stunned?
- electrical stunning and electrocution
- live chilling in ice slurry
- CO2
- knocking head
- spiking
How are fish bled? What is shucking?
cut and remove gills or cut the caudal vessels of the tail
remove shell and scales
At what 2 temperatures are fish typically kept? How do they types of fish determine shelf life?
- chilling (0 C) for days
- freezing (-18 C) for months
dark-fleshed and white-fleshed fish are at high quality and edible longer than shellfish, since they are filter feeders likely to be contaminated by pathogens
What parts of the fish are likely to cause spoilage? How does this happen?
skin, gills, and gut
harbors high levels of microbes (and their enzymes) and enzymes that are able to putrify proteins and cause fat to become rancid
What are the 2 most important factors that accelerate fish spoilage? What factors originate from the slaughterhouse?
- rise in temperature above 32 F (freezing)
- low glycogen in fish flesh = low lactic acid = high pH favorable for microbial growth
shucking, gutting, washing, cleanliness of fishrooms and ice in which the fish are stunned or preserved
What are the 4 spoilage stages due to fish nutrient breakdown?
- flesh undergoes rigor mortis, where ATP is converted into inosine and the dominant bacteria change
- inosine is converted into hypoxanthine and ammonia levels increase due to conversion of urea and amines; trimethylamineoxide is converted into trimethylamine and bacteria growth occurs
- hypoxanthine is converted into xanthine and uric acid; TMA, volatile bases and acids increase; rapid bacterial growth
- proteolysis; TVB and TVA increase, hydrogen sulfide is produced and flesh is deteriorated
What 2 bacteria are commonly found in the fish gut? What type of bacteria are commonly found in the flora?
Clostridium tetani and botulinum
psychrophilic - cold-loving (fish are cold-blooded)
What bacteria typically cause fish spoilage at chilling, room, and high temperatures?
CHILLING - Pseudomonas, Achromobacter, Flavobacterium
ROOM - E. coli, Proteus, Serratia, Sarcina, Clostridium
HIGH - Micrococcus, Bacillus
What are the 2 types of discoloration caused by spoilage? What causes each?
- yellow/greenish yellow - Pseudomonas fluorescens and other yellow micrococci
- red/pink - Sarcina, Micrococcus, Bacillus, molds, or yeast
What is the major component associated with odor and spoilage of fish? What is used for chemical detection?
trimethylamine (TMA) - increases in tissues after 5-10 days
total volatile acids and bases (ammonia)
What 5 qualities are used to assess fish for consumption?
- organoleptic - color, defects, firmness
- microbiological tests
- parasitological examination
- chemical - pH, moisture, fat, minerals (Hg, Pb, Cd, Zn)
- metabolic products - TMA, ammonia, hydrogen sulfide, histamine, tetrodotoxin, algal toxins
What are the 4 normal organoleptic qualities of fish? Spoiled?
NORMAL:
1. EYES: convex with clear corneas
2. GILLS: bright red/pink mucous
3. SKIN: well-differentiated colors, glossy, transparent slime
4. ODOR: sharp, sea-like, iodine-like, metallic
SPOILED:
1. EYES: sunken, cloudy, discolored cornea
2. GILLS: bleached, discolored and coated with thick slime
3. SKIN: loses color, coated with yellow, knotted slime
4. ODOR: stale cabbage water, sour, wet matches, ammonical (TMA!)
What microorganisms convert non-proteinaceous compounds and amino acids into byproducts with bad odor? What agents are produced?
Pseudomonas, Alteromonas, Flavobacterium, Acinetobacter, Aeromonas, Moraxella
- ATP
- TMA
- ammonia
- hydrogen sulfide
What are the 3 indicators of bad fish quality?
- volatile bases = basic nitrogenous compounds, like ammonia, TMA, and DMA
- nucleotides = degradations from ATP, like inosine monophosphate, hypoxanthine, xanthine, uric acid
- lipid oxidation = peroxides, hydroperoxides, aldehydes
What are 3 common biological hazards in seafood?
- bacteria
- virus
- parasites
What product accounts for most seafood-related infectious outbreaks? What are the 2 most common agents? Where do they originate from?
shellfish (64%), finfish (31%)
- Norovirus - gastroenteritis associated with the consumption of raw shellfish (oysters)
- Vibrio - shellfish
fecal contamination and consumption of raw or undercooked fish
What are the major bacterial, viral, and parasite hazards from seafood consumption?
BACTERIAL: Salmonella, Shigella, Vibrio*
VIRAL: Norovirus, Hepatitis A
PARASITE: Anisakis, Giardia, Paragonimus, Diphyllobothrium
In what fish is Vibrio most prevalent? What does it cause?
shellfish
- acute, severe cholera
- fatal gastroenteritis
- wound infections, amputations
- septicemia/shock
In what fish are trematodes most prevalent? What 2 are major causes of disease? What do they infect?
carp
- Clonorchis
- Opisthorchis
gall bladder, bile duct, liver (CANCER!)
What chemical hazards are common in fish and shellfish?
FISH - histamine (scromboid) from amino acids and tetrodotoxin from pufferfish
SHELLFISH - algae stored in shellfish muscle and metals
What are the 2 most common chemical hazards associated with seafood consumption? What heavy metal is most common?
- scromboid (histidine —> histamine) - anaphylaxis
- ciguatoxin
mercury
What are the most common fish species that cause scromboid toxicity? What are the 3 strongest bacterial producers? What are some others?
tuna, mackerel, mahi mahi
- Morganella morganii
- Klebsiella pneumoniae
- Hafnia alvei
Enterobacteriaceae, Vibrio, Clostridium, Lactobacillus, Pseudomonas, Aeromonas
What are the 2 most common causes of the production of histamine in scromboid poisoning?
- some degree of spoilage
- fish improperly stored at the incorrect temperature
What are some non-scromboid fish that produce large amounts of histamine by themselves?
- mahi mahi
- bluefish
- amberjack
- swordfish
- herring
- sardines
- anchovies
How is scromboid produced in fish? What are some symptoms in humans?
histidine is converted into histamine by histidine decarboxylase in spoilage bacteria when fish are not properly stored at the correct temperature (cannot be inactivated by normal heat processing)
- low blood pressure
- rash
- headache
- itchiness
- blurred vision
- cramps
- diarrhea
What are the 3 major fish that produce tetrodotoxin? What bacteria produces it? How does it cause disease?
- boxfishes (square/triangular)
- pufferfishes (globose)
- filefishes and triggerfish (laterally compressed)
Aeromonas, Pseudomonas, Vibrio
sodium channel blocker that blocks neural activity, causing fatal flaccid paralysis
What are the 4 major algae toxins affecting shellfish? What one affects fish?
- saxitoxin - paralytic shellfish poisoning
- okadaic acid dinophysis - diarrhea shellfish poisoning
- brevetoxins - neurolytic shellfish poisoning
- domoic acid - amnesic shellfish poisoning
- phytoplankton
ciguatoxin (dinoflagellates) - most common in carnivorous fish in tropical areas
When does chilling of the whole fish take place?
after catching, harvesting, and killing
