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Food Contamination and Poisoning

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Overview of food contamination and poisoning

Contaminated food and water are major causes of morbidity and mortality in the developing world, particularly among children.1 Even though contaminated foods are responsible for more than half of diarrheal episodes, efforts to prevent diarrheal diseases often overlook food safety. Food safety is at least as important as providing a safe water supply and sanitation services.

Recent changes in human demographics, food preferences, microbial adaptation and lack of support for public health resources have led to the emergence of new as well as established illnesses caused by food contamination and poisoning.2 The very young, the elderly and the immunocompromised people are frequently affected from food-borne illnesses.

Selection of appropriate treatment of food poisoning depends on identification of the responsible pathogen and the status of hydration. Spontaneous recovery is the most likely outcome once supportive measures such as fluid and electrolyte replacement are addressed. The increase in the antimicrobial resistance for some pathogens has led to judicious use of antibiotics.


Causes of food contamination and poisoning

Food-borne illness usually arises from improper handling, preparation or storage of food. Food contamination sources include unclean hands, polluted water, flies, pests, inadequately cleaned utensils and an unsanitary environment. Cross-contamination during food preparation (contact between raw and cooked foods) is also responsible for food-borne illnesses. 

In many countries, bacterial food-borne infections are the commonest cause of intestinal disease. Salmonella and Campylobacter spp. account for over 90% of all reported cases of bacteria-related food poisoning worldwide.3 The poisoning is caused by toxins released by the microorganisms. These toxins cause inflammation of the stomach and intestines causing the typical gastrointestinal (GI) symptoms.

Among the viruses, the norovirus and hepatitis A virus are the most important food-borne pathogens with regard to the number of outbreaks and people affected in the Western world.4 In addition to bacteria and viruses, pesticide, chemicals, heavy metals, parasite and fungi are some of the other contaminants.


Symptoms of food contamination and poisoning

Symptoms of food poisoning depend on the type and the amount of contaminant eaten. The symptoms can develop rapidly, within 30 min or slowly, worsening over days to weeks. In general, most of the common contaminants cause nausea, vomiting, diarrhea, abdominal cramps and fever. 

In severe cases, patients may present with bloody stools, dehydration, fever with chills, muscle aches and weakness. Rarely food poisoning may lead to paralysis or death. The signs or symptoms of dehydration include excessive thirst, dry mouth, little or no urination, dizziness, sunken eyes and loss of skin turgor.


Diagnosis and Evaluation of food contamination and poisoning

Food poisoning is usually diagnosed by specific laboratory tests that identify the specific organism which cause the illness. Bacteria such as Campylobacter, Salmonella spp. and E. coli are identified through stool culture. Parasites can be identified through microscopic examination of ova and cysts. Viruses are usually identified by stool samples examination for genetic markers of a specific virus.

Blood cultures should be obtained when bacteremia or systemic infection is suspected. Direct antigen detection tests and molecular biology techniques are available for rapid identification of certain bacterial, viral and parasitic agents.

A differential diagnosis should include the underlying medical conditions such as irritable bowel syndrome, inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis, malignancy, use of medication (particularly antibiotic), malabsorption syndromes and immune deficiencies.


Management of food contamination and poisoning

Many episodes of food poisoning are self-limiting and require only fluid replacement and supportive care. Oral rehydration is indicated for patients with mild-to-moderate dehydration and intravenous therapy may be required for those with severe dehydration. 

Routine use of antidiarrheal agents is not recommended as many of these agents have serious adverse effects in infants and young children. Antibiotics are often not required and may prolong fecal excretion of certain bacteria.5 In very serious cases of food poisoning, medications may be given to stop the abdominal cramps and vomiting.


Alternative Therapies/Home Remedies for food contamination and poisoning

These include the following: 

  • Avoid eating for few hours or reduce overall food intake.
  • Drink plenty of fluids.
  • Avoid milk products, spicy and oily food, alcohol and fresh fruit.
  • Recommend the BRAT diet: banana, rice, applesauce and toast.
  • Drink ginger tea for indigestion, heartburn and nausea.


Prevention food contamination and poisoning
  • Frequently wash hands, utensils and food surfaces.
  • Avoid cross-contamination. Keep raw foods separate from ready-to-eat foods.
  • Refrigerate leftovers promptly. Do not let food stand at room temperature.
  • Avoid contaminating surfaces and foods with the juices of uncooked meats.
  • Do not thaw frozen foods at room temperature.
  • Throw away bulging or leaking cans or any food that smells spoiled.
  • Sanitize food preparation surfaces regularly.


Surveillance and Reporting of Food-Borne Illness

Food-borne disease reporting is not only important for disease prevention and control, but also allows more accurate assessments of the burden in the community. As infectious diarrhea spreads easily and is highly contagious, appropriate reporting will help in rapid and definitive identification of the etiologic agent and thus, control an outbreak of a disease. Occasionally, reporting may lead to the identification of a previously unrecognized agent of food-borne illness.

Written by: Healthplus24 team
Date last updated: November 09, 2012