Presentation is loading. Please wait.

Presentation is loading. Please wait.

Public health risks from fish and fish products Craig Burton Scottish Food Enforcement Officers Perth April 08.

Similar presentations

Presentation on theme: "Public health risks from fish and fish products Craig Burton Scottish Food Enforcement Officers Perth April 08."— Presentation transcript:

1 Public health risks from fish and fish products Craig Burton Scottish Food Enforcement Officers Perth April 08

2 Potential hazards Potential public health risks can arise from –Toxins –Parasites –Xenobiotes (Man-made substances)

3 Definitions Toxin –A poisonous substance produced by an organism Parasite –An organism that lives on or in another and derives nutrition from the host with a detrimental effect on the host. Xenobiote –A substance that is not of biological origin found in the ecosystem or body

4 Fish toxins 3 main toxins and several minor ones –Ciguatera –Tetrodotoxin –Scombroid poisoning –Clupeoid fish poisoning –Gempylid poisoning –Hallucinatory fish poisoning –Ichthyohaemotoxic poisoning –Ichthyohepatotoxic poisoning –Ichthyootoxic poisoning –Elasmobranch poisoning

5 Ciguatera Most serious toxin world-wide and commonest Mainly tropics and sub-tropics –Between 35 o N and 35 o S Mainly reef fish species – 400 species implicated –Barracuda –Grouper –Snapper –Sea Bass –Coral Trout –Rock Cod –Jacks / Tevally –Parrot Fish –Moray Eel

6 Ciguatera No external indication of toxicity Heat stable Possible 5 toxins involved –Ciguatoxin –Maitotoxin –Scaritoxin –Palytoxin –Okadic acid Cause – dinoflagellates (Gambierdiscus toxicus)

7 Ciguatera Symptoms: –Various, 2 – 12 hours after ingestion –Gastro-intestinal (nausea, vomiting, cramps, diarrhoea) –Cadiovascular (hypotension, tachycardia, bradycardia) –Neurological (headache, joint pain, delirium, paralysis, coma) –Sensation (itch, burning, numbness, tingling, dysaesthesia) –Skin lesions Can be fatal (0.1 - 10%)

8 Ciguatera Can be treated –Treat symptoms and provide support Best tactic – Avoidance –Be cautious of large reef fish – especially predators –Do not eat fish liver, gonads or intestines –Caution if evidence of algal blooms –Sale of some fish species banned in some areas / seasons

9 Tetrodotoxin Most famous fish toxin Japanese ‘Fugu’ Toxin found in –Puffer Fish –Ocean Sunfish –Porcupine Fish Occurs in –Ovaries –Liver –Intestines

10 Tetrodotoxin Heat stable Slightly water soluble Neurotoxin –65 mg lethal –Has medical uses as a pain killer Symptoms: 5 – 40 minutes (to 3 hours) –General (weak, pale, dizzy, unco-ordinated, salivation, sweating) –Neurological (numbness, paraesthesia, muscle twitching, paralysis) –Gastro-intestinal (nausea, vomiting, diarrhoea, pain) –Cardiovascular (chest pain, irregular pulse, hypotension)

11 Tetrodotoxin Treatment –Respiratory support and general care –Can improve rapidly –Full resolution Can be fatal (up to 60% if untreated and can kill in 17 mins)

12 Scombroid toxin Fish spoilage problem Associated with –Tuna (all species) –Mackerels (all species) –Herring –Sardine –Anchovy –Bluefish –Amberjack –Kingfish

13 Scombroid toxin Cause –Fish treated incorrectly after capture or during storage –Left in the sun –Kept at room temperature for hours What happens –Bacteria (Proteus, Clostridium, Salmonella, Klebsicila, Escherichia) convert Histidine in the muscles to Suarine (histamine-like)

14 Scombroid toxin External Indication –Fish taste sharp, bitter or peppery Laboratory confirmation –Histamine > 100 µM (mg) per 100 g fish muscle (Codex Std < 20 mg 100g -1 )

15 Scombroid toxin Symptoms: 20 – 60 mins –General (dry mouth, thirst, burning throat, cannot swallow, headache, metallic taste, weakness, pain, fever) –Gastro-intestinal (nausea, vomiting, diarrhoea, cramps) –Cardiovascular (palpitations, tachycardia, hypotension, ST depression) –Skin (general redness, itching, urticaria) –Respiration (bronchospasm, distress, cyanosis)

16 Scombroid toxin Often mistaken for fish allergy Treat with anti-histamines (steroids) Rarely fatal Usually resolves 12 – 16 h, but can last days

17 Rarer toxins Clupeoid fish poisoning –Anchovy –Herring –Sardine –Rapid onset (minutes) –Often fatal –Liver failure (if survive) –Possibly related to Ciguatera poisoning Gempylid poisoning –Escolars and pelagic mackerels –Diarrhoea

18 Rarer toxins Hallucinatory fish poisoning –Mullet –Goatfish –Drummers –Rockcod –Surgeon fish –Rare and localised –Heat stable –Rapid onset - < 2 h –Symptoms –Impaired consciousness –Hallucination –Bizarre dreams –Paranoia –Resolves < 24 h

19 Rarer toxins Ichthyohaemotoxic poisoning –Drinking fish blood, especially freshwater eels –Heat labile, protein-bound –Symptoms –Gastro-intestinal (nausea, vomiting, pain) –Neurological (numbness, weakness, paralysis) –Can be fatal Ichthyohepatotoxic poisoning –Eating fish livers (tuna, mackerel, bass, grouper, snapper, sandfish) –Like vitamin A overdose Ichthyootoxic poisoning –Eating fish eggs / roe (eg Barbel roe, but can affect caviar by bacterial spoilage) –Rare –Symptoms –Gastro-intestinal (nausea, vomiting, diarrhoea) –Neurological (tinnitus, respiratory distress, coma) –General (dry mouth) –Resolves in days

20 Rarer toxins Elasmobranch poisoning –Associated with eating sharks and rays –Often from liver and gonads (but also in muscle) –Heat stable –Water soluble –Symptoms –Gastro-intestinal (nausea, vomiting, diarrhoea, pain) –Neurological (numbness, tingling, weakness, visual, paralysis, delirium, coma) –Cardiovascular (tachycardia, thready pulse) –Skin (itchy, peel off) –General (headache, pain, prostration) –Can be fatal –Recovery 5 - 20 days

21 Parasites Affect freshwater and marine fish 76 recognised pathogenic species 3 main groups: –Nematodes (Round worms) –Trematodes (Flukes) –Cestodes (Tape worms) Also –Acanthocephala

22 Parasites Problems mainly associated with raw or lightly processed fish Typical ‘risk’ dishes –Raw fish (eg Sashimi, Sushi) –Cold-smoked fish –Lightly salted (cured) fish (eg Gravfisk) –Pickled fish (eg Roll-mop herring) –Marinated fish –Undercooked fish

23 Parasites Penetrate human gut if ingested –Inflammation –Ulceration –Granuloma formation –Can migrate to other organs (serious) Infection rare in UK (but 40 – 50 million people (5-7%) affected world-wide, mainly Asia) Can be of short duration (days) or can be chronic (decades)

24 Nematodes (Round worms) Main condition –Anisakiasis (eosinophilic phlegmonous enteritis, eosinophilic granuloma) Main causal agents –Herring Worm (Anisakis simplex) –Cod Worm (Pseudoterranova decipiens) –Eustrongylides spp –Gnathostoma sprinigerum (FW - Thailand) –Angiostrongylus cantonensis (FW) Worms mainly found in fish gut, but move to muscle tissue after death

25 Nematodes Symptoms (within hours) –Abdominal pain –Nausea –Vomiting –May cough up larvae –After 1-2 weeks, mimics Crohn’s disease (IBS) –Other (more serious) if migration to other organs –Brain –Heart –Lungs

26 Nematodes Common fish hosts –Herring –Cod –Pollock –Haddock –Alaskan pollock –Mackerel –Anchovy –Tuna –Salmon –Squid

27 Trematodes (Flukes) Fish are intermediate host Several genera can infect humans –Heterophyes spp –Microphallus spp –Nanophyetus spp –Opisthorchis spp –Chlonorchis spp –Metagonimus spp –Paragonimus spp (crustacea)

28 Trematodes Symptoms –Depends on main site of infection of fluke –Liver flukes –Chlonorchis spp –Opisthorchis spp –Abdominal pain –Nausea –Diarrhoea / Constipation –Eosinophilia –Cholangitis –Cholelithiasis –Pancreatitis –Cholangiocarcinoma –Heptamegaly –Malnutrition

29 Trematodes Symptoms –Intestinal flukes –Heterophyes spp –Metagonimus spp –Abdominal pain –Diarrhoea –Heart (muscle and valves) –Brain

30 Trematodes Symptoms –Lung flukes –Paragonimus spp –Abdominal pain –Diarrhoea –Fever –Cough –Urticaria –Hepatospleanomegaly –Lung abnormality –Eosinophilia –Cough –Expectoration –Haemoptysis –Brain –Other organs

31 Trematodes Symptoms –Other “fish flu” –Nanophyetus spp –Abdominal discomfort –Diarrhoea –Nausea –Fatigue –Weight loss –Eosinophilia

32 Trematodes Common fish hosts –Mullet (Mugil spp) –Sea Bass (Dicentrarchus spp) –Herring –Salmonids –Tilapia –FW fish (carps)

33 Cestodes (Tape worms) Fish are intermediate host Main concern 2 genera –Diplogonoporus spp –Diphyllobothrium spp –Diphyllobothrium latum –Broad tapeworm –Human optimum host –Grows to 10 m –Long lived (decades)

34 Cestodes Symptoms –Can be none (asymptomatic) –Abdominal discomfort –Diarrhoea –Vomiting –Weight loss –Vitamin B12 deficiency –Pernicious anaemia –Intestinal obstruction

35 Cestodes Common fish hosts –Pike –Perch –Burbot –Salmonids –Drums (Serranids) –Blue Whiting –Anchovy –Sardine –Turbot

36 Prevention of parasite infection Freeze fish –EU requirement (853/2004) –Freeze to -20 o C for 24 h –Other advice (FDA) –Blast freeze to -35 o C for 15 h –Freeze to -23 o C for 168 h –Freeze or store at -20 o C for minimum of 7 d Cook fish to > 60 o C throughout depth Candling and removal (minimise risk) Belly flap removal (minimise risk) Gut at sea or as kill (and cure) can reduce risk

37 Xenobiotes Several non-biological substances of health concern can occur in fish and fish products –From the environment –Hydrocarbons –Persistent Organic Pollutants (Dioxins, Polychlorinated biphenols [PCB], Organophosphates, Organochlorides) –Polycyclic Aromatic Hydrocarbons (PAH) –Heavy metals (Pb, Hg (CH 3 -Hg), Cd etc) –Radionucleotides –Synthetic hormones (freshwater)

38 Xenobiotes –From direct intervention –Veterinary medicine residues (aquaculture) –Polycyclic Aromatic Hydrocarbons (PAH) (processing) –Colourants (processing)

39 Xenobiotes Some have permitted maximum levels set in legislation –International (Codex Alimetarius) –European (1881/2006, 2377/90, 94/36/EC) –UK (Contaminants in Food Regs 2007) UK fisheries and aquaculture monitored Imports should be certificated (EU approved residue monitoring plan in export country)

40 Craig Burton 01967 431573 07876 035771 (Mobile) Thank you. Enjoy your fish!

Download ppt "Public health risks from fish and fish products Craig Burton Scottish Food Enforcement Officers Perth April 08."

Similar presentations

Ads by Google