Non-bacterial Food Poisoning

Question 1

What is the mechanism of action of mercury intoxications?

Answer 1

Reaction with free sulfhydryl (SH) groups, forming complexes that inhibit protein function

Affects kidneys and CNS, impairing organ, cell, or subcellular structure.

Question 2

What are the main symptoms of mercury intoxications?

Answer 2

Numbness of lips and tongue, numbness of legs, hands, and neck, general disorders of muscular coordination, respiratory paralysis, death, cardiac deceleration, headache, increased sweating, feeling of thirst

Symptoms can vary in severity.

Question 3

What are the types of shellfish poisoning?

Answer 3

Amnesic Shellfish Poisoning (ASP), Paralytic Shellfish Poisoning (PSP), Diarrhoeic Shellfish Poisoning (DSP), Neurologic Shellfish Poisoning (NSP)

Each type is associated with specific toxins and symptoms.

Question 4

What is the mechanism of action of saxitoxin?

Answer 4

Acts on CNS, reversibly blocks the inflow of ions through Na+ and Ca2+ channels, blocks action potentials

Responsible for Paralytic Shellfish Poisoning (PSP).

Question 5

What are the three different groups of toxins associated with Diarrhoeic Shellfish Poisoning (DSP)?

Answer 5

• Acidic Toxins: okadaic acid & dinophysis toxins
• Neutral Toxins: pectenotoxins
• Sulphated Toxins: yessotoxins

Produced by dinoflagellates such as Dinophysis spp. and Prorocentrum spp.

Question 6

What causes Neurologic Shellfish Poisoning (NSP)?

Answer 6

Consumption of molluscan shellfish contaminated with brevetoxins

Brevetoxins are primarily produced by the dinoflagellate Karenia brevis.

Question 7

What are aflatoxins and their primary sources?

Answer 7

Produced by many species of Aspergillus, e.g., Aspergillus flavus and Aspergillus parasiticus

Highly carcinogenic and found in contaminated grains and nuts.

Question 8

What symptoms are associated with Neurologic Shellfish Poisoning (NSP)?

Answer 8

Paresthesia, vertigo, malaise, abdominal pain, nausea, diarrhoea, motor weakness, ataxia

Mean time to onset is 3 hours, with a dose-response relationship.

Question 9

What is the primary toxin responsible for Amnesic Shellfish Poisoning (ASP)?

Answer 9

Domoic acid (DA)

Produced by diatoms of the genus Pseudonitzschia.

Question 10

What is ricin, and what are its effects?

Answer 10

A toxin from the seeds of the Castor Oil Plant (Ricinus communis), causes severe necrosis of the intestinal wall, multi-organ failure, and death

Most dangerous routes of administration are inhalation and injection.

Question 11

What is the mechanism of action of ricin?

Answer 11

B subunit binds to galactose on cell membrane, leads to endocytosis, A subunit blocks protein synthesis in ribosomes

This process results in cell death.

Question 12

What are lectins and their effects on the human body?

Answer 12

Thermo-labile proteins that selectively bind to saccharide groups, can agglutinate erythrocytes and inhibit transport through cell walls

Found in >80 plant species, mainly legumes.

Question 13

What is the recommended maximum daily caffeine intake for an average adult?

Answer 13

<400mg per day

Energy drinks can contain significantly higher amounts.

Question 14

What is the half-life of methylmercury?

Answer 14

Around 70 days

Mainly localized to the liver and brain.

Question 15

What are the different forms of mercury?

Answer 15

• Elementary mercury
• Salts of inorganic mercury
• Easily absorbable organic mercury

Each form has different environmental and health impacts.

Question 16

What is the leading cause of foodborne illness?

Answer 16

Norovirus

Responsible for 58% of domestically-acquired foodborne illnesses.

Question 17

What are the common symptoms of Hepatitis A and Hepatitis E?

Answer 17

• Fever
• Fatigue
• Nausea
• Jaundice
• Diarrhoea

Similar incubation times of 2-6 weeks.

Question 18

What is the legal limit for aflatoxins in animal feed within the UK?

Answer 18

0.05 ppb

The legal limit for milk and dairy products is also 0.05 ppb.

Question 19

What is the route of infection for Trichinella spiralis?

Answer 19

Worm lives in the intestines of pigs, humans ingest eggs via the faecal-oral route

Leads to Trichinosis (Trichinellosis).

Question 20

What treatment is recommended for Echinococcus infections?

Answer 20

Surgical intervention or albendazole

Alveolar manifestations are more severe and have a high mortality rate.

Question 21

What is the mercury concentration in canned tuna according to the FDA?

Answer 21

0.35µg/g

This concentration translates roughly to 35µg in 100g of tuna.

Question 22

What is the half-life of methylmercury?

Answer 22

Around 70 days

Methylmercury mainly localizes to the liver and brain.

Question 23

What percentage of the body burden of methylmercury is borne by the brain?

Answer 23

10-20%

This indicates significant accumulation in the central nervous system.

Question 24

Is there a treatment for methylmercury poisoning?

Answer 24

No treatment available.

Question 25

What are the allowable tolerance doses for methylmercury and inorganic mercury?

Answer 25

* Methylmercury: 1.6 µg/kg body weight * Inorganic mercury: 4 µg/kg body weight ## Footnote For a 70kg adult, this translates to 112µg and 280µg respectively.

Question 26

What industrial applications utilize inorganic mercury?

Answer 26

* Production of plastics * Paper manufacturing * Electric batteries

Question 27

What does acute poisoning with mercuric salts primarily target?

Answer 27

Gastrointestinal tract and kidneys.

Question 28

What are the symptoms of acute mercury poisoning?

Answer 28

* Abdominal pain * Vomiting * Bloody diarrhea

Question 29

What is Anisakiasis?

Answer 29

A parasitic disease caused by anisakid nematodes that can invade the stomach wall or intestine.

Question 30

How is Anisakis simplex infection typically treated?

Answer 30

Endoscopy or surgery.

Question 31

What are the primary forms of helminths?

Answer 31

* Nematodes (roundworms) * Cestodes (tapeworms) * Trematodes (flukes)

Question 32

What is the main source of liver fluke infection?

Answer 32

Eating raw watercress or plants contaminated with immature parasite larvae.

Question 33

What are the symptoms of tapeworm infestation?

Answer 33

* Diarrhea * Fatigue * Stomach cramps and pain * Chronic hunger or lack of appetite * Unintended weight loss * Weakness

Question 34

What is the treatment for tapeworm infestation?

Answer 34

One dose of praziquantel or niclosamide.

Question 35

What are the primary metabolites of caffeine?

Answer 35

* Paraxanthine (84%) * Theobromine (12%) * Theophylline (4%)

Question 36

What are the common types of glycoalkaloids found in food plants?

Answer 36

* α-solanine * α-chaconine

Question 37

What is the normal glycoalkaloid level in tubers destined for human consumption?

Answer 37

20 – 100mg/kg.

Question 38

What are some examples of non-bacterial food poisoning sources?

Answer 38

* Poisonous plants (e.g., rhubarb leaves, kidney beans) * Chemical contaminants (e.g., bleach, mercury) * Mycotoxigenic fungi (e.g., aflatoxin) * Poisonous shellfish and fish (e.g., scombrotoxin)

Question 39

What are the symptoms of xanthine alkaloid overdose?

Answer 39

* Nausea * Diarrhea * Vomiting * Stomach cramps * Cardiac dysrhythmia * Headache * Dizziness

Question 40

What is the life-threatening dose of solanine?

Answer 40

400mg.

Question 41

What are the three primary types of mycotoxins mentioned?

Answer 41

* Fumonisins * Ochratoxins * Aflatoxins

Question 42

Which mycotoxin is most prevalent and linked to urinary tract tumors?

Answer 42

Ochratoxin A (OTA).

Question 43

What is the main health effect of aflatoxin consumption?

Answer 43

Hepatocellular carcinoma.

Question 44

What is the protective potential of phytoestrogens?

Answer 44

Potential protective effects against colon cancer and osteoporosis.

Question 45

What is the mechanism of action of alkaloids?

Answer 45

Inhibit acetylcholinesterase and disrupt cell membranes.