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Uncommon Food Poisoning. Dr LAU Fei-lung COS (AED) UCH. (Natural) toxins in food (plants). Cyanogenic glycoside Beans Potatoes Fresh Jin Zhen Star fruit Aflatoxin Ackee fruit. 1) Cyanogenic glycoside. Phytotoxin in 2000 plants 25 cyanogenic glycosides
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Uncommon Food Poisoning Dr LAU Fei-lung COS (AED) UCH
(Natural) toxins in food (plants) • Cyanogenic glycoside • Beans • Potatoes • Fresh Jin Zhen • Star fruit • Aflatoxin • Ackee fruit
1) Cyanogenicglycoside • Phytotoxin in 2000 plants • 25 cyanogenic glycosides • From 4 amino acids or nicotinic acid • Cyanogenic glucose Aldehyde or ketone glycoside + + cyanohydria HCN ß-glycosidase spontaneous or hydroxynitrile lipase
1) Cyanogenicglycoside • Acute HCN toxicity: Headache, dizzy, mental confusion, stupor, twitching , convulsion, coma. Lethal dose :0.5-3.5 mg /kg • Chronic HCN toxicity : Goitre and cretinism: HCN converted to thiocyanate interfere with thyriod Iodine uptake Tropical toxic neuropathy
Fruit seeds or stone • Seeds of apple, apricots, plum, prunes, cherries, peaches • Flesh of fruit not toxic • Kernals in pits chewed • Release hydrogen cyanide from Amygdalin • Lethal dose 0.5-3mg/kg • Bitter almond南杏poisoning commonest
Fruit seeds or stone • ~ 6 mg HCN/ bitter almond • 5-10 raw almonds fatal for young children • Mis-belief Amygdalin can prevent & cure cancer • Lady with cancer on 4 amp of laetrile (3g amygdalin) daily, die with 24 hrs after ingestion of 3.5 ampoules.
Cassavapoisoning ?in Philippine • 9/3/05 after taking fried cassava ball • 500 pupils sick , 30 died • ?cyanide poisoning ( ill prepared cassava) • Use white (bitter) cassava flour • Later prove to be organophosphate poisoning • Diarrhoea, salivation , frothing , convulsion , small pupils • Pesticide bottle to contain cooking oil .
Cassava (木薯) • Grow in tropical climate • (important root crop in Pacific island, Latin America, Africa & some Asian countries) • Tuber root (30% starch) + leaves
Cassava (木薯) Poisoning also seen in China: • under/uncooked cassava • Contain linamarin glucose, Acetone & HCN Cyanide Content Processing Sweet cassava 15 – 50 mg/kg Peeling & full cooking Better cassava 50 – 400 mg/kg Heap fermentation
Bamboo Shoots • 1200 bamboos, limited edible • Contain Taxiphyllin glucose, HCN & hydroxybenzaldehyde • 1000 mg/kg in apical part & • 8000 mg/kg in immature shoot tip • Reduced markedly after harvesting • Cooking for 2 hrs HCN to 3%
Cycas Seed (台灣鐵樹種子) • Contain Cycasin & Neocycasin • Reported in PCC Taiwan • 21 cases: 1990-2001 • 70% mistaken as edible food, others health promotion, cancer prevention, cosmetic use • Washed & cooked
Cycas Seed • Onset of symptom 30 min to 7 hours • Ingested 1 to 30 seeds • Nearly all develop G.I. Symptom (vomiting) • All recovered in 24 hours • Blood cyanide & thiocyanate elevated but not toxic
2) Beans • Green bean 四季豆 • Phytohaemagglutin destroyed by soaking & cooking • Onset 1-3 hours • Symptoms: nausea, vomiting & diarrhoea • Partial cooking to 80oC even more toxic
Castor Bean (萞麻毒素)蓖麻籽 • Contain ricin – in ‘mash’ after bean processed to caster oil • Potent cytotoxin – inhibit ribosomal protein synthesis • Weak haemagglutinin • Lethal dose: 1mg (oral); 0.5mg (injection)
Castor Bean • 1 seed can kill a child (not toxic if swallow unchewed) • Bulgarian writer in 1978, killed by KGB with ricin pellet • S/S depend on route of exposure
Ricin Ingestion: • Vomiting, bloody diarrhoea, abd pain • Within 6 hours • Progress to dehydration & shock • Followed by brain, liver, kidney failure • Death within 36-72 hours • Inhalation: • Delay of 8-18 hours • Cough, SOB, weakness, fever, ARDS • dermal: • dermatitis
3) Potatoes • Contain glycoalkaloid – solanine (龍葵碱) • Usually low level & non-toxic • Greening, sprouting, rotting toxin • Bitter taste • Solanine cannot destroyed by cooking
3) Potatoes • Cause oral burning sensation, severe abdominal pain vomiting • Can cause respiratory depression, cerebral edema & haemolysis
4) Fresh Jian Zhen(鮮金針) • Bud of some lily harested before blossoming • Flower & roots contain colchicine • Inadequate soaking & cooking • Cause abdo pain, vomiting & diarrhoea • Commercial & dry Jin Zhen colchicine destroyed during processing
5) Star Fruit • Averrhoa carambola • Tropical fruit popular in Asia • In uraemic patient • Cause hiccup, confusion, convulsion , agitation • Treatable by intensified dialysis
5) Star Fruit • Postulated related to oxalate • Healthy patient develop acute oxalate nephropathy (ARF) ingesting large amount sour star fruit juice • Star fruit high oxalate content precipitate in brain causing neurological symptom
6)Aflatoxins(黃曲霉毒素) • Toxin produced by Fungi • Aspergillus Flavus & A. parasiticus: green mould • Grow an mouldy hay, grain & peanuts • Aflatoxin:heat resistant no taste/smell/color
6)Aflatoxins (黃曲霉毒素) • Acute poisoning: vomiting, abdominal pain, pulmonary edema, convulsions coma, & death with cerebral edema & fatty liver, heart & kidney • Chronic: chronic liver disease & CA liver
6)Aflatoxins (黃曲霉毒素) Accepted limited in HK • 20 mg/kg peanut oil • 15 mg/kg other food • FEHD survey (1998-2000): • 526 food samples • 23% peanut & peanut oil +ve (1.6 – 20.0 mg/kg)
Jamaican Vomiting Sickness-Ackee friut • Endemic in Jamaica and Africa (+/- USA) • Acute illness with intractable vomiting ,convulsion and coma associating with hypoglycaemia and acidaemia
Jamaican Vomiting Sickness • 2-6 hours after eating Ackee Fruit • Unriped ackee fruit contains hypoglycins A and B • Cause hypoglycaemia by binding carnitine and Coenzyme A