Food Poisoning

Dr Mohd Kaleem Khan

Assistant ProfessorDepartment Of Forensic Medicine

JNMCH AMU Aligarh

Causes Of Food Poisoning Bacteria and their toxins (bacterial food poisoning).

Food poisoning through plants (natural food poisons).

Food poisoning through animals, for example, poisonous fish, mussel, etc.

Chemicals: intentionally added such as flavouring agents

in processed food, colouring agents, preservatives, etc. Accidentally added such as pesticides and insecticides.

Migrants from the packaging materials and metallic contaminants etc.

BACTERIAL FOOD POISONING

Food – poisoning is an acute gastro-enteritis caused by the ingestion of the food or drink contaminated with either living bacteria or their toxins Bacterial food poisoning may be divided into two groups—

Infection typeMicroorganisms that multiply in the gastrointestinal tract producing infection producing infection, for example, Salmonella group of organisms

Toxin type. Incubation period is short (1–6 hours ),

Toxin is usually preformedStaphylococcus aureus or bacillus cereusToxin can be detected in the food

Incubation period is longer(between 8 and 16 hours), The organism is present in the food and produces

toxin after being ingested. Clostridium perfringens, Toxin can be detected in food or stool specimens.

Staphylococcus aureus

It is perhaps the commonest cause of food poisoning. I.P.:1–8 hours. Sources: Meat, milk, dairy products, potato, egg, salad,

etc. Pathogenesis: Production of enterotoxin. Features: Abrupt onset, intense vomiting. Recovery : is usually in 24–48 hours.Diagnosis: stool culture. No treatment usually necessaryRestore fluids and electrolytes.

Bacillus cereus

Two types of toxins. One is a heat-labile,

Large molecular weight protein Diarrhoea Incubation period is 8–16 hours.

The other toxin is a heat-stable, Low molecular weight peptideSevere emetic (vomiting) Incubation period is 3–6 hours.

Sources are fried rice, dried fruit, powder milk, etc.

Diagnosis is through culture of contaminated food.

Clostridium perfringens

Spores of the organism persist in soil, dust and foods (raw meat, poultry, fish, vegetables, legumes, gravies, etc.).

I.P.: 8–16 hours. Pathogenesis: Enterotoxin produced in food

and in the gut causes hyper secretion in small intestine.

Symptoms: Abrupt onset of profuse diarrhoea; vomiting occasionally.

Recovery is usual in 1–4 days. Clostridia demonstrable in food and faeces.

Clostridium botulinum Toxin, a heat-labile , destroyed by heat at 80° c for 10 minutes) Seven immunogenic types (A to G) of the toxin have been identified. Types a, b and e toxins often cause human botulism I.P.: 6 hours to 1 week. blocks acetylcholine at neuro-muscular junction , Bilaterally symmetrical

descending motor paralysis (bulbar paralysis). diplopia, dysphagia, dry mouth, dysphonia, Dysarthria, respiratory embarrassment, etc

Treatment: clearing of the airways, ventilation and intravenous polyvalent antitoxin.

Toxin can be demonstrated in food and serum. Sources: under-processed sausages, potted meats, tinned fish, canned

acidic vegetables, fruits,

Postmortem Appearances

An important feature in most cases (except botulism) is gastrointestinal congestion.

In some cases, there may be ulceration of intestinal mucosa.

Botulism fatalities are usually characterised by a lack of postmortem findings.

Asphyxial signs may be present

Isolated cases of food poisoning may have medico legal importance, an intended victim of homicide.

Cases of mass food poisoning are not uncommon in India,

Contamination may result from unhygienic measures during the preparation or storage of articles of food.

The public health authorities must be contactedDoctors coming across cases of food poisoning from

public eateries such as hotels and canteens must report them to the public health authorities.

Botulism in India (the main source of Clostridium botulinum) is relatively less as canned food less popular.

POISONOUS FOODS

Is restricted to poisoning by articles of food that contain poison derived from plants animals and inorganic chemicals.

Metallic contamination of food or drink and migrants from packaging material may also be included in this entity.

Lathyrus sativus (Kesari Dal)This is a drought-resistant pulse. staple food for low-income groups in some areas of Central

India. Consumption of seeds >30% of the total diet for more than

six months can cause paralysis (neurolathyrism).The active neurotoxic principle is B(N) oxalylamino-alanine, The condition manifests as a spastic paralysis of the lower

limbs due probably to a localised lesion of the pyramidal tracts.

In mild cases, there is only stiffness and weakness of the legs.

Death in the acute stage is very rare. Sclerosis of the lateral columns is seen o postmortem

examination.

Mushrooms

Amanita phalloides and Amanita muscaria are the common varieties of poisonous fungi.

Active principles are phalloidins (only in Amanita species), amatoxins (most important toxic principle) and virotoxins.

Amatoxins are powerful inhibitors of cellular protein synthesis.

Cells with high replication rates (liver, kidney, intestinal cells) develop necrosis.

Liver usually shows centrilobular necrosis.

Symptoms

There is usually an incubation period of 6–12 hours. Three stages may be recognised:

(i ) Gastroenteritis stage: lasting for 24 hours and is characterised by cholera-like diarrhoea, abdominal pain, vomiting, fever, etc.

(ii ) Latent stage: lasting for a variable period during which most of the symptoms subside. However, a patient may return in 2–3 days in a moribund condition.

(iii)Hepato-renal stage: showing jaundice, confusion, delirium, metabolic acidosis, Coagulopathy, renal failure and coma.

DiagnosisAmatoxins detected by Meixner Test.

Treatmentdecontamination, correction of dehydration, forced

diuresis and other supportive measures.

Argemone mexicanaCommon names: prickly poppy, pila dhatura,

ujarkanta, kutila,Belonging to the family papaveraceae and grows

wild in the countryside all over india.Small black seeds, which resemble mustard

seeds.About 1% of argemone oil as an adulterant is

necessary to produce clinical epidemic dropsy. Pressed on a slide, they burst with a report,

whereas mustard seeds collapse silently.

Active Principles

Seeds contain Berberine Protopine,

Oil containsSanguinarine Dihydrosanguinarine.

Epidemic dropsy.

This conditionpresents with vomiting, diarrhoea, oedema,

especially of the feet and sometimes a generalised anasarca may be seen.

Pleural and pericardial effusions, hepatomegaly, and congestive heart failure with breathlessness may also be noticed.

Hair loss is noted in some cases. Death may result from myocardial damage.

Medicolegal Aspects

Adulteration of mustard oil with argemone oil is common in certain parts of India.

The recent outbreak of epidemic dropsy in Delhi and neighbouring states (1998) claimed nearly a hundred lives, and has projected the catastrophic consequences of edible oil adulteration.