Seafood Safety and Natural Marine Toxins

Seafood Safety andSeafood Safety andNatural Marine ToxinsNatural Marine Toxins

• Robert J. PriceRobert J. Price• Food Science & TechnologyFood Science & Technology• Sea Grant Extension ProgramSea Grant Extension Program• UC DavisUC Davis

Major Causes of Seafood-borne Major Causes of Seafood-borne IllnessIllness

• Live molluscan shellfishLive molluscan shellfish• VibrioVibrio species species• Norwalk-like virusesNorwalk-like viruses• Natural marine toxinsNatural marine toxins

• Scombroid fish poisoningScombroid fish poisoning• Ciguatera fish poisoningCiguatera fish poisoning

Estimated Cases Per YearEstimated Cases Per Year

• Norwalk-like virusNorwalk-like virus 100,000100,000• Scombroid fish poisoningScombroid fish poisoning 8,0008,000• Ciguatera fish poisoningCiguatera fish poisoning 1,6001,600• VibrioVibrio species species 1,0601,060• Hepatitis AHepatitis A 1,0001,000• SalmonellaSalmonella 200200• ShigellaShigella 200200• Clostridium perfringensClostridium perfringens 200200

Natural Marine ToxinsNatural Marine Toxins

• Scombroid fish poisoning (histamine)Scombroid fish poisoning (histamine)• Ciguatera fish poisoningCiguatera fish poisoning• Shellfish toxins (ASP, DSP, NSP, Shellfish toxins (ASP, DSP, NSP,

PSP)PSP)• TetrodotoxinTetrodotoxin• GempylotoxinGempylotoxin• PfiesteriaPfiesteria

Scombroid Fish PoisoningScombroid Fish Poisoning

• Named for the family Scomberidae Named for the family Scomberidae (tunas and mackerels)(tunas and mackerels)

• Can involve any fish containing high Can involve any fish containing high levels of free histidinelevels of free histidine

• Bacteria break down free histidine into Bacteria break down free histidine into histaminehistamine

Histamine FormationHistamine Formation

DiaminesDiamines

CadaverineCadaverine

HH22NN––CHCH22–CH–CH22–CH–CH22–CH–CH22–CH–CH22–NH–NH22

PutrescinePutrescine

HH22NN––CHCH22–CH–CH22–CH–CH22–CH–CH22–NH–NH22


• Source:Source: improperly handled improperly handled (time/temperature abuse) mahi mahi, (time/temperature abuse) mahi mahi, tuna, bluefish, sardines, mackereltuna, bluefish, sardines, mackerel

• Range:Range: worldwide worldwide


• Onset:Onset: immediate to 30 minutes immediate to 30 minutes• Initial symptoms:Initial symptoms: tingling or burning tingling or burning

sensation in the mouth, rash on the sensation in the mouth, rash on the upper body, drop in blood pressure, upper body, drop in blood pressure, headache, itching of the skinheadache, itching of the skin

• Later symptoms:Later symptoms: nausea, vomiting, nausea, vomiting, and diarrheaand diarrhea

• Duration:Duration: 3 hours to several days 3 hours to several days


• Treatment: Treatment: antihistaminesantihistamines• Control:Control: proper chilling and proper chilling and

temperature controltemperature control• FDA guideline:FDA guideline: 50 ppm 50 ppm

Scombrotoxin OutbreaksScombrotoxin Outbreaks

• 1979-80:1979-80: >200 cases (imported mahi >200 cases (imported mahi mahi)mahi)

• 1986: 1986: 10 cases (Pacific yellowtail)10 cases (Pacific yellowtail)• 1988:1988: 9 cases (yellowfin tuna) 9 cases (yellowfin tuna)• 1988: 1988: 8 cases (mahi mahi)8 cases (mahi mahi)• 1998:1998: 4 cases (yellowfin tuna) 4 cases (yellowfin tuna)• 2000:2000: 21 cases in California (escolar) 21 cases in California (escolar)

Ciguatera Fish PoisoningCiguatera Fish Poisoning

• Four toxins:Four toxins: structure not determined structure not determined• Source:Source: certain species of fish feeding on certain species of fish feeding on

several algae species including several algae species including GambierdiscusGambierdiscus

• Range:Range: • Tropical and subtropical waters worldwideTropical and subtropical waters worldwide• U.S.: East coast, Puerto Rico, Hawaii, Virgin U.S.: East coast, Puerto Rico, Hawaii, Virgin

IslandsIslands• Toxins:Toxins: heat stable heat stable


• Onset:Onset: <6 hours<6 hours• Symptoms:Symptoms:

• Gastrointestinal:Gastrointestinal: nausea, vomiting, nausea, vomiting, diarrheadiarrhea

• Neurological:Neurological: numbness and tingling numbness and tingling around mouth, joint pain, muscle ache, around mouth, joint pain, muscle ache, headache, temperature sensory reversalheadache, temperature sensory reversal

• Cardiovascular:Cardiovascular: arrhythmia, bradycardia, arrhythmia, bradycardia, tachycardia, reduced blood pressuretachycardia, reduced blood pressure


• Duration:Duration:• Usually self-limiting within several daysUsually self-limiting within several days• Rarely some neurological symptoms may Rarely some neurological symptoms may

persist for months or yearspersist for months or years

• Treatment:Treatment:• Treat symptomsTreat symptoms


• Control:Control: • Mouse bioassayMouse bioassay• ““Cigua-check” test kit availableCigua-check” test kit available• Enzyme immunoassay under evaluationEnzyme immunoassay under evaluation• Obtain fish from safe harvest areasObtain fish from safe harvest areas

• Commonly implicated species:Commonly implicated species:• Groupers, barracudas, snappers, jacks, mackerel, Groupers, barracudas, snappers, jacks, mackerel,

and triggerfishand triggerfish

• FDA guideline:FDA guideline: no guideline no guideline

Ciguatera OutbreaksCiguatera Outbreaks

• 1981:1981: Puerto Rico, 49 cases, 2 deaths Puerto Rico, 49 cases, 2 deaths (barracuda, amberjack, blackjack)(barracuda, amberjack, blackjack)

• 1987:1987: Caribbean, 57 cases (fish casserole) Caribbean, 57 cases (fish casserole)• 1988:1988: Florida, >100 cases (hogfish) Florida, >100 cases (hogfish)• 1992:1992: California, 25 cases (flag cabrilla) California, 25 cases (flag cabrilla)• 1994:1994: California, several cases (yellowtail) California, several cases (yellowtail)• 1995:1995: Guam (sea weed?) Guam (sea weed?)

Shellfish ToxinsShellfish Toxins

• Amnesic shellfish poisoningAmnesic shellfish poisoning• Diarrheic shellfish poisoningDiarrheic shellfish poisoning• Neurotoxic shellfish poisoningNeurotoxic shellfish poisoning• Paralytic shellfish poisoningParalytic shellfish poisoning

Amnesic Shellfish PoisoningAmnesic Shellfish Poisoning


• Source:Source: Molluscan shellfish (mussels) Molluscan shellfish (mussels) feeding on algae ( feeding on algae (Pseudo-nitzschia Pseudo-nitzschia spp.), viscera of Dungeness crab and spp.), viscera of Dungeness crab and anchoviesanchovies

• Range:Range: Northeast and northwest Northeast and northwest North AmericaNorth America


• Onset:Onset:• Gastrointestinal symptoms within 24 hoursGastrointestinal symptoms within 24 hours• Neurological symptoms within 48 hoursNeurological symptoms within 48 hours

• Symptoms:Symptoms: • Gastrointestinal: vomiting, diarrhea, Gastrointestinal: vomiting, diarrhea,

vomitingvomiting• Neurological: confusion, memory loss, Neurological: confusion, memory loss,

disorientation, seizure comadisorientation, seizure coma


• Duration: Duration: • Self-limiting within several daysSelf-limiting within several days• Short-term memory loss can be permanentShort-term memory loss can be permanent

• Control:Control: • HPLC laboratory procedureHPLC laboratory procedure• Obtain shellfish from approved watersObtain shellfish from approved waters• Monitoring of coastal water and shellfishMonitoring of coastal water and shellfish

Amnesic Shellfish Poisoning Amnesic Shellfish Poisoning

• FDA guideline:FDA guideline: • 20 ppm domoic acid in all fish20 ppm domoic acid in all fish• 30 ppm domoic acid in viscera of Dungeness crab30 ppm domoic acid in viscera of Dungeness crab

• Outbreaks:Outbreaks:1987: Prince Edward Island, Canada1987: Prince Edward Island, Canada• 156 cases, 3 deaths, 12 with permanent short-156 cases, 3 deaths, 12 with permanent short-

term memory loss (mussels)term memory loss (mussels)

1991: Washington state1991: Washington state• 24 cases (razor clams)24 cases (razor clams)

Diarrheic Shellfish PoisoningDiarrheic Shellfish Poisoning

Okadaic acid and its derivativesOkadaic acid and its derivatives


• Source:Source: molluscan shellfish feeding molluscan shellfish feeding on algae (on algae (DinophysisDinophysis and and Prorocentrum Prorocentrum spp.)spp.)

• Range:Range: Japan, southeast Asia, Japan, southeast Asia, Scandinavia, western Europe, Chile, Scandinavia, western Europe, Chile, New Zealand, eastern CanadaNew Zealand, eastern Canada

• Toxins:Toxins: heat stable heat stable


• Onset: Onset: 30 minutes to 3 hours30 minutes to 3 hours• Symptoms:Symptoms: mild diarrhea, nausea, mild diarrhea, nausea,

vomiting, abdominal pain, chills, vomiting, abdominal pain, chills, headache, feverheadache, fever

• Duration:Duration: 2-3 days with or without 2-3 days with or without treatmenttreatment


• Control:Control: • Mouse bioassayMouse bioassay• HPLC procedureHPLC procedure• Molluscan shellfish from approved watersMolluscan shellfish from approved waters

• FDA guideline:FDA guideline: • 0.2 ppm okadaic acid plus 35-methyl 0.2 ppm okadaic acid plus 35-methyl

okadaic acid (DXT 1) in all fishokadaic acid (DXT 1) in all fish

Neurotoxic Shellfish PoisoningNeurotoxic Shellfish Poisoning

Polyether brevetoxins (6 toxins + 2 phosphorus containing Polyether brevetoxins (6 toxins + 2 phosphorus containing toxins)toxins)

Neurotoxic Shellfish Neurotoxic Shellfish PoisoningPoisoning

• Source:Source: molluscan shellfish feeding molluscan shellfish feeding on algae (on algae (Gymnodinium breveGymnodinium breve))

• Range:Range: gulf of Mexico and southern gulf of Mexico and southern Atlantic coast in U.S.; New ZealandAtlantic coast in U.S.; New Zealand

• Toxins:Toxins: heat stable heat stable


• Onset: Onset: a few minutes to a few hoursa few minutes to a few hours• Symptoms:Symptoms: tingling and numbness of tingling and numbness of

the lips, tongue, and throat, muscular the lips, tongue, and throat, muscular aches, dizziness, cold hot sensation aches, dizziness, cold hot sensation reversal, diarrhea, vomitingreversal, diarrhea, vomiting

• Duration:Duration: a few hours to several days a few hours to several days


• Control:Control: • Mouse bioassayMouse bioassay• HPLCHPLC• Commercial immunoassayCommercial immunoassay• Obtain molluscan shellfish from approved watersObtain molluscan shellfish from approved waters

• FDA guideline:FDA guideline: • 0.8 ppm brevetoxin-2 equivalent (20 mouse 0.8 ppm brevetoxin-2 equivalent (20 mouse

units/100g) in clams, mussels and oystersunits/100g) in clams, mussels and oysters


• Outbreaks:Outbreaks:• Sporadic and continuous along the gulf Sporadic and continuous along the gulf

coast of Florida, North Carolina, and Texascoast of Florida, North Carolina, and Texas

Paralytic Shellfish PoisoningParalytic Shellfish Poisoning

• Saxitoxins (12-20 analogs)Saxitoxins (12-20 analogs)


• Source:Source: contaminated molluscan contaminated molluscan shellfish feeding on algae shellfish feeding on algae ((AlexandriumAlexandrium, , PyrodiniumPyrodinium, , GymnodiniumGymnodinium spp.) spp.)

• Range:Range: tropical to temperate waters tropical to temperate waters worldwideworldwide


• Onset: Onset: ½ to 2 hours½ to 2 hours• Symptoms:Symptoms: tingling, burning, numbness, tingling, burning, numbness,

drowsiness, incoherent speech, respiratory drowsiness, incoherent speech, respiratory paralysisparalysis

• Duration: Duration: respiratory support within 12 respiratory support within 12 hours of exposure results in complete hours of exposure results in complete recoveryrecovery


• Control:Control: • Mouse bioassayMouse bioassay

• Monitoring of coastal waters and shellfishMonitoring of coastal waters and shellfish

• Obtain molluscan shellfish from approved Obtain molluscan shellfish from approved waters waters

• FDA guideline:FDA guideline: • 0.8 ppm saxitoxin equivalent (80μg/100g) in all 0.8 ppm saxitoxin equivalent (80μg/100g) in all

fishfish

PSP OutbreaksPSP Outbreaks

• 1976-89:1976-89: 42 outbreaks in Alaska 42 outbreaks in Alaska• 1980:1980: California, 98 cases, 2 deaths California, 98 cases, 2 deaths

(oysters)(oysters)• 1990:1990: Massachusetts, 6 cases Massachusetts, 6 cases

(mussels)(mussels)• 1990:1990: Alaska, 11 cases Alaska, 11 cases

TetrodotoxinTetrodotoxin


• Source:Source: • Gonads, liver, intestines, and skin of Gonads, liver, intestines, and skin of

about 80 species of puffer fish, blowfish about 80 species of puffer fish, blowfish or fuguor fugu

• Also found in the California newt, Also found in the California newt, parrotfish, frogs (parrotfish, frogs (AtelopusAtelopus genus), blue- genus), blue-ringed octopus, starfish, octopus, and ringed octopus, starfish, octopus, and xanthid crabsxanthid crabs


• Range:Range: • Primarily the Indo-Pacific OceanPrimarily the Indo-Pacific Ocean• Other cases and deaths have occurred Other cases and deaths have occurred

from puffer fish from the Atlantic Ocean, from puffer fish from the Atlantic Ocean, Gulf of Mexico, and Gulf of CaliforniaGulf of Mexico, and Gulf of California


• Onset: Onset: 20 minutes to 3 hours20 minutes to 3 hours• Initial symptoms:Initial symptoms: numbness of the lips and numbness of the lips and

tonguetongue• Secondary symptoms:Secondary symptoms: prickling of the face prickling of the face

and extremities, a sensation of lightness or and extremities, a sensation of lightness or floating, headache, epigastric pain, nausea, floating, headache, epigastric pain, nausea, diarrhea and/or vomitingdiarrhea and/or vomiting

• Tertiary symptoms:Tertiary symptoms: increasing paralysis and increasing paralysis and death within 4-6 hoursdeath within 4-6 hours


• Control:Control: • Mouse bioassayMouse bioassay• HPLC methodHPLC method• Do not eat puffer fish or avoid improperly Do not eat puffer fish or avoid improperly

prepared pufferfishprepared pufferfish

• FDA guideline:FDA guideline: • Puffer fish may not be imported except Puffer fish may not be imported except

under specific authorization from FDAunder specific authorization from FDA

Tetrodotoxin OutbreaksTetrodotoxin Outbreaks

• Japan:Japan:• 1974-1983, 646 cases, 179 deaths1974-1983, 646 cases, 179 deaths• 30-100 persons per year mostly from home 30-100 persons per year mostly from home

preparation and consumptionpreparation and consumption• Mortality about 50%Mortality about 50%

• California:California: • 1996, 3 cases, no deaths1996, 3 cases, no deaths

GempylotoxinGempylotoxin

• Symptoms:Symptoms: diarrhea, generally without pain diarrhea, generally without pain or crampingor cramping

• Control:Control: avoid specific fish species avoid specific fish species• FDA guideline:FDA guideline: escolar should not be escolar should not be

importedimported• Outbreaks:Outbreaks: California, 8+ cases, March 2000California, 8+ cases, March 2000

PfiesteriaPfiesteria

planetENN, September 30, 1996planetENN, September 30, 1996

Pfiesteria piscicidaPfiesteria piscicida

• Discovered in 1988Discovered in 1988• Phytoplankton (dinoflagellate)Phytoplankton (dinoflagellate)

• Up to 24 life stages (4 may be toxic)Up to 24 life stages (4 may be toxic)• Eats other organisms, usually algaeEats other organisms, usually algae

PfiesteriaPfiesteria Blooms Blooms

• PfiesteriaPfiesteria may produce toxins that numb fish, may produce toxins that numb fish, allowing the microbes to feed on the fishallowing the microbes to feed on the fish

• High concentrations of High concentrations of PfiesteriaPfiesteria can cause can cause deep lesions on fish and may kill themdeep lesions on fish and may kill them

• Blooms usually exist for only a few hoursBlooms usually exist for only a few hours• Several massive fish kills in estuaries Several massive fish kills in estuaries

along coastal North Carolinaalong coastal North Carolina

PfiesteriaPfiesteria

• No cases of seafood-borne illness have been No cases of seafood-borne illness have been reportedreported

• Human health effects have occurred in Human health effects have occurred in laboratories where researchers were working laboratories where researchers were working in close proximity to high concentrations of in close proximity to high concentrations of the microorganismthe microorganism

• Anglers, water skiers, fish-kill monitors have Anglers, water skiers, fish-kill monitors have complained of skin lesions, headaches, complained of skin lesions, headaches, lightheadedness, short-term memory losslightheadedness, short-term memory loss

Information SourcesInformation Sources

• FDA’s Bad Bug BookFDA’s Bad Bug Book• http://vm.cfsan.fda.gov/~mow/intro.htmlhttp://vm.cfsan.fda.gov/~mow/intro.html

• Seafood Network Information CenterSeafood Network Information Center• http://seafood.ucdavis.eduhttp://seafood.ucdavis.edu

Seafood Safety and Natural Marine Toxins

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