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Toxicology

Food Poisoning

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Food poisoning

It is any illness resulting from the consumption of contaminated food.
It is a common, usually mild, but sometimes deadly illness.
Typical symptoms include nausea, vomiting, abdominal cramping, and diarrhoea that occur suddenly (within 48 hours) after consuming a contaminated food or drink.
Depending on the contaminant, fever and chills, bloody stools, dehydration, and nervous system damage may follow.
These symptoms may affect one person or a group of people who ate the same thing (called an outbreak).

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Statistics About Food Poisoning

In USA, food poisoning causes about 76 million illnesses, 325,000 hospitalizations, and up to 5,000 deaths each year
About 300 million cases annually in India
Worldwide, diarrhoeal illnesses are among the leading causes of death. Travellers to developing countries often encounter food poisoning in the form of traveller's diarrhoea or "Montezuma’s revenge."

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Causes of Food Poisoning

The known causes of food poisoning can be divided into two categories: infectious agents and toxic agents.
Infectious agents include viruses, bacteria, and parasites.
Toxic agents include poisonous mushrooms, improperly prepared exotic foods (such as barracuda), or pesticides on fruits and vegetables.

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Agents of Poisoning

Types of contaminant

Bacteria:- Salmonellae, Campylobacter, Bacillus cereus, Staphylococcus aureus, Escherichia coli (E coli), Shigella (traveller’s diarrhoea), Clostridium botulinum (botulism), Vibrio cholerae,
Viruses:- Noroviruses, Rotavirus, Hepatitis A
Parasites:- Giardia (beaver fever), Cryptosporidium,
Toxic agents-Mushroom toxins, Aflatoxins, Ciguatera poisoning, Scombroid, Pesticides,
Radiation

Viruses account for most food poisoning cases where a specific contaminant is found.

BACTERIAL FOOD POISONING

Infection type: organisms belong mainly to salmonella, proteus, coli, streptococcus, shigella.

Toxic type, is due to ingestion of preformed toxin in prepared food.

Incubation period of staphylococcal food poisoning is 1-6 hours

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Noroviruses are a group of viruses that cause a mild illness (often termed "stomach flu") with nausea, vomiting, diarrhoea, abdominal pain, headache, and low-grade fever. These symptoms usually resolve in two to three days. It is the most common viral cause of adult food poisoning and is transmitted from water, shellfish, and vegetables contaminated by faeces, as well as from person to person. Outbreaks are more common in densely populated areas such as nursing homes, schools and cruise ships (hence why the virus is also known as the "Cruise Ship Illness"). The term Noroviruses has been approved as the official name for this group of viruses. Several other names have been used for Noroviruses, including Norwalk-like viruses, caliciviruses (because they belong to the virus family Caliciviridae), and small round structured viruses.

��Rotavirus: Causes moderate to severe illness with vomiting followed by watery diarrhoea and fever. It is the most common cause of food poisoning in infants and children and is transmitted from person to person by faecal contamination of food and shared play areas.

��Hepatitis A: Causes mild illness with sudden onset of fever, loss of appetite, and feeling of tiredness followed by jaundice, which is a yellowing of the eyes and skin. It is transmitted from person to person by faecal contamination of food.

�Bacteria can cause food poisoning in two different ways. Some bacteria infect the intestines, causing inflammation and difficulty absorbing nutrients and water, leading to diarrhoea. Other bacteria produce chemicals in foods (known as toxins) that are poisonous to the human digestive system. When eaten, these chemicals can lead to nausea and vomiting, kidney failure, and even death. ��

Salmonellae: Salmonellae are bacteria that may cause food poisoning; the illness itself is often referred to as Salmonella or Salmonella infection. Salmonellae cause a moderate illness with nausea, vomiting, crampy diarrhoea, and headache, which may come back a few weeks later as arthritis (joint pains). In people with impaired immune systems (such as people with kidney disease or HIV/AIDS or those receiving chemotherapy for cancer), Salmonellae can cause a life-threatening illness. The illness is transmitted by undercooked foods such as eggs, poultry, dairy products, and seafood.

��Campylobacter: Causes mild illness with fever, watery diarrhoea, headache, and muscle aches. Campylobacter is the most commonly identified food-borne bacterial infection encountered in the world. It is transmitted by raw poultry, raw milk, and water contaminated by animal faeces.

��Staphylococcus aureus: Causes moderate to severe illness with rapid onset of nausea, severe vomiting, dizziness, and abdominal cramping. These bacteria produce a toxin in foods such as cream-filled cakes and pies, salads (most at risk are potato, macaroni, egg, and tuna salads, for example) and dairy products. Contaminated salads at picnics are common if the food is not chilled properly.

��Bacillus cereus: Causes mild illness with rapid onset of vomiting, with or without diarrhoea and abdominal cramping. It is associated with rice (mainly fried rice) and other starchy foods such as pasta or potatoes. It has been speculated that this bacteria may also be used as a potential terrorist weapon.

��Escherichia coli (E coli): Causes moderate to severe illness that begins as large amounts of watery diarrhoea, which then turns into bloody diarrhoea. There are many different types of this bacteria. The worst strain can cause kidney failure and death (about 3%-5% of all cases). It is transmitted by eating raw or undercooked hamburger, unpasteurized milk or juices, or contaminated well water. Outbreaks of food poisoning due to E. coli have also occurred following ingestion of contaminated produce.

��Shigella (traveller's diarrhoea): Causes moderate to severe illness with fever, diarrhoea containing blood or mucus or both, and the constant urge to have bowel movements. It is transmitted in water polluted with human wastes.

��Clostridium botulinum (botulism): Causes severe illness affecting the nervous system. Symptoms start as blurred vision. The person then develops problems talking and overall weakness. Symptoms then progress to breathing difficulty and the inability to move arms or legs. Infants and young children are particularly at risk. It is transmitted in foods such as home-packed canned goods, honey, sausages, and seafood.

Because botulism can be released in the air, it is considered a potential biological weapon for terrorists.��Vibrio cholerae: Causes mild to moderate illness with crampy diarrhoea, headache, nausea, vomiting, and fever with chills. It strikes mostly in the warmer months of the year and is transmitted by infected, undercooked, or raw seafood.

�Parasites rarely cause food poisoning. When they do, they are usually swallowed in contaminated or untreated water and cause long-lasting but mild symptoms. ��

Giardia (beaver fever): Causes mild illness with watery diarrhoea often lasting one to two weeks. It is transmitted by drinking contaminated water, often from lakes or streams in cooler mountainous climates.

The infection can also be spread from person to person by food or other items contaminated with faeces from an infected person.��Cryptosporidium: Causes moderate illness with large amounts of watery diarrhoea lasting two to four days. May become a long-lasting problem in people with poor immune systems (such as people with kidney disease or HIV/AIDS or those on chemotherapy for cancer). It is transmitted by contaminated drinking water.

�Toxic agents are the least common cause of food poisoning. Illness is often an isolated episode caused by poor food preparation or selection (such as picking wild mushrooms). ��

Mushroom toxins: Illness can range from mild to deadly depending on the type of mushroom eaten. Often there is nausea, vomiting, and diarrhoea. Some types of mushrooms produce a nerve toxin, which causes sweating, shaking, hallucinations, and coma.

��Ciguatera poisoning: Caused by eating fish that contains toxins produced by a marine algae called Gambierdiscus toxicus. It can cause moderate to severe illness with numbness of the area around the mouth and lips that can spread to the arms and legs, nausea, vomiting, muscle pain and weakness, headache, dizziness, and rapid heartbeat. The toxin may cause sensory problems in which hot things feel cold and cold things feel hot. It is transmitted by eating certain large game fish from tropical waters-most specifically barracuda, grouper, snapper, and jacks. According to the CDC, ciguatera has no cure. Symptoms may disappear in days or weeks, but may persist for years.

��Scombroid: Causes mild to moderate illness with facial flushing, burning around the mouth and lips, peppery-taste sensations, a red rash on the upper body, dizziness, headache, and itchy skin. Severe symptoms may include blurry vision, respiratory distress, and swelling of the tongue and mouth. Symptoms typically last from four to six hours, and rarely more than one or two days. It is transmitted in seafood, mostly mahi-mahi and tuna, but can also be in Swiss cheese.

��Pesticides: Cause mild to severe illness with weakness, blurred vision, headache, cramps, diarrhoea, increased production of saliva, and shaking of the arms and legs. Toxins are transmitted by eating unwashed fruits or vegetables contaminated with pesticides.

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BOTULISM

It is caused by neurotoxin, an exotoxin of clostridium botulinum multiplied in the food e.g. tinned meat| fish, fruits etc.
The calculated single fatal dose for an adult is 0.00005 mg. In food fatal dose is 0.01 mg, The toxin paralyses the nerve ending.
The incubation period is 12 to 30 hours.
Signs and Symptoms:

There is nausea, vomiting, constipation, (There are no symptoms of gastroenteritis i.e. no diarrhoea) ocular , pharyngeal paralysis, salivation, sometimes aphonia. Excessive fatigue, diplopia. marked muscular weakness. The patient is conscious till death, which is preceded by coma or-delirium. Bulbar palsy and descending paralysis is seen.

Differential diagnosis of botulism includes Tetanus, Epilepsy and Acute gastroenteritis.
Management

Artificial Respiration, antitoxin- 50000 units and symptomatic treatment�

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Lathyrus Sativus (Khesari dal)

Consumption exceeding 30% of the total diet for more than 6 months; produces lathyrism.
The active neurotoxic principle is B(N)-oxalyl aminoalanine -> BOAA.
The continuous use of L. sativus produces neurolathvrism,

Characterised by progressive spastic paraplegia,
Sphincters, sensation and mental faculties are preserved.�

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Argemone Mexicana

Mustard oil is often adulterated with the Argemone oil Causing epidemic dropsy
Argemone oil contains toxic alkaloids:

sanguinarine , berberine, and protopine.

Sign & Symptoms of Epidemic dropsy

Sudden non inflammatory, bilateral oedema of legs, Hypersecretory glaucoma, Diarrhoea, CCF are seen ( no convulsions).
Sanguinarine interferes with the oxidation of pyruvic acid, which accumulates in blood

Tests for detection of Argemone oil are
(i) Nitric acid test: The colour becomes brown to orange-red shows presence of Argemone oil, positive when concentration is 0.25 percent.

(ii) Paper chromatography test: This is the most sensitive test. It can detect argemone oil up to 0.0001 percent in all edible oils and fats.-

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Poisonous Fungi�(Mushrooms)

Species Poisonous

Amanita muscaria ( fly agaric)
Amanita phalloids (destroying angel)

Action

Active principle

Amanita muscaria

Muscarine & Muscardine

Amanita phalloids

Phaloidin, Phallon, Alpha & Beta amanatincyclopeptides with a thioamide structure

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Clinical picture

Early onset

Cholinergic(muscarinic) effect in less than 2 hours
Psychedelic more potent than magic mushroom
This is typical of muscaria
Treatment

Large doses of atropine

Late onset

Abdominal pain, vomiting, diarrhoea,
Signs of acute liver and renal damage
Severe hypoglycaemia and electrolyte disturbance
Occurs more than 5 hours after ingestion
Death common
Typical of phalloides poisoning
Treatment on general principle& Antiphalloidin serum

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Poisonous Fungi

Non-specific gastroenteritis
It may not be easy to differentiate the three kinds of clinical effects in early stages
Fatal dose-

Uncertain, 300 mg has caused death
1/3 of top of phalloides caused death

Fatal period

Usually within 24 hours.
May be delayed up to 3 to 8 days

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Treatment

Gastric lavage with Kmno₄
Activated finely powdered charcoal
Saline purgative
Atropine Initially IV may be needed
Cal.gluconate I.V.
I.V.glucose with insulin,Vit-K,C, B-complex & Thioctic acid 300mg (For protection of liver & kidneys)
Pethidine for pain
Prednisolone 100mg daily
Wide spectrum antibiotic
Fluid & electrolyte balance
Symptomatic

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P.M.Findings

Inflammatory signs in mucosa of G.I.T.
Fatty degeneration of Liver & heart
Necrosis of renal tubules
Areas of necrosis, haemorrhage & Congestion of brain
Subpleural & sub pericardial haemorrhage

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Medico-legal Aspects

Accidental
Inhabitants of eastern Siberia use the fungus habitually for its C.N.S. stimulant effect

Spirit of exhilaration, talkativeness & intoxication is caused
In winter months when fungus is not available some of them drink their own urine to recover alkaloids

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Ptomaines

General

These are alkaloidal bodies formed as a result of bacterial decomposition of protein

Cadaveric alkaloids

Ptomaines formed in dead tissues

Active principles

Most of ptomaines are non poisonous Except
Neurine & Mydaleine

These are produced in traces 5-7 days after death in cadavers
Produced in food when very much rotten

Medico-legal

These are not the cause of food poisoning

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Clinical Picture in General

Usually food poisoning is not serious, and the illness runs its course in 24-48 hours.
The symptoms can develop rapidly, within 30 minutes, or slowly, worsening over days to weeks depending on the

Agent &
Quantity eaten

Incubation period of staphylococcal food poisoning is 1-6 hours

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Sign & Symptoms

Most of the common contaminants cause nausea, vomiting, diarrhoea, and abdominal pain,
In serious cases associated fever, headache or fatigue. may be present.
More than 250 known diseases can be transmitted through food.

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Medical Care to be Provided

Nausea, vomiting, or diarrhoea lasting for more than two days even with ORS.
Children under three years.
The abdominal symptoms are associated with a low-grade fever.
Symptoms began after recent foreign travel.
Other family members or friends who ate the same thing are also sick.
Diarrhoea with vomiting.
The ill person has a disease or illness that weakens his/her immune system (for example, HIV/AIDS, cancer and undergoing chemotherapy, kidney disease).
The ill person cannot take normally prescribed medications because of vomiting.
The ill person has associated nervous system symptoms such as slurred speech, muscle weakness, double vision, or difficulty in swallowing.
Anaemia, loss of hair is associated with GI symptoms

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Emergency Admission

The ill person or caretaker considers the situation to be an emergency.
Collapse, or problems with vision.
Temperature 101°F or above with the abdominal symptoms.
Signs of dehydration
Abdomen swells indicating gut paralysis.
Jaundice.
Blood in vomitus or having bloody stool.
Anuria or blood in urine.
The ill person develops problems with breathing, speaking, or swallowing.
One or more joints swell or a rash breaks out on skin.

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Management

Rehydration

ORS
IV fluid

Antiemetic
Antidiarrhoeal / broad spectrum chemotherapeutic agents.
Activated Charcoal Slurry
Gastric lavage/ Emetic for pesticide poisoning
Antidote/ antitoxins
General Management
Regular ‘hand washing’ single most important preventive measure

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Medico-Legal Aspects

Food poisoning is a health hazard associated with adulteration , putrefaction, bad preservation of food material.
Poverty forcing people to eat or drink unhealthy material.
Homicidal poisoning faked as food poisoning
Poisoning of water supply as an attempt to kill or injure large population.
Additionally, there are possible new global threats to the world's food supply through terrorist actions using food toxins as weapons.

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