Foodborne Illness and Causes

- Major Foodborne Illnesses and Causes

Foodborne illnesses are usually contagious or toxic and are caused by bacteria, viruses, parasites or chemicals entering the body through contaminated food. Chemical pollution can cause acute poisoning or long-term illness, such as cancer. 

Many foodborne illnesses can lead to long-term disability and death. Some examples of food hazards are listed below.

• Bacteria
• Virus
• Parasite
• Prion
• Chemicals

- Bacteria

Salmonella, Campylobacter, and EHEC are some of the most common foodborne pathogens, affecting millions of people each year, sometimes with serious and fatal consequences. Symptoms may be fever, headache, nausea, vomiting, abdominal pain, and diarrhea. Foods associated with outbreaks of salmonellosis include eggs, poultry, and other products of animal origin. Foodborne cases of Campylobacter are mainly caused by raw milk, raw or undercooked poultry, and drinking water. EHEC has been linked to unpasteurized milk, undercooked meat, and contaminated fresh fruits and vegetables.

Listeria infection can cause miscarriage in pregnant women or death of newborn babies. Although the incidence of illness is relatively low, the serious and sometimes fatal health consequences of Listeria, especially in infants, children and the elderly, make it one of the most serious foodborne infections. Listeria is found in unpasteurized dairy products and a variety of ready-to-eat foods, and can grow at refrigerated temperatures.

Vibrio cholerae can infect humans through contaminated water or food. Symptoms may include abdominal pain, vomiting, and profuse watery diarrhea, which can quickly lead to severe dehydration and possibly death. Rice, vegetables, millet porridge and various types of seafood have been linked to cholera outbreaks.

Antimicrobial agents, such as antibiotics, are critical to treating infections caused by bacteria, including foodborne pathogens. However, their overuse and misuse in veterinary and human medicine has been linked to the emergence and spread of drug-resistant bacteria, resulting in ineffective treatment of infectious diseases in animals and humans.

- Virus

Some viruses can be spread by eating food. Norovirus is a common cause of foodborne infections characterized by nausea, severe vomiting, watery diarrhea, and abdominal pain. The hepatitis A virus is also spread through food and can cause long-term liver disease, usually through raw or undercooked seafood or contaminated raw produce.

- Parasite

Some parasites, such as fish-borne trematodes, can only be spread through food. Others, such as tapeworms such as Echinococcus or Taenia spp., may infect humans through food or direct contact with animals. Other parasites, such as roundworms, Cryptosporidium, Entamoeba histolytica or Giardia, enter the food chain through water or soil and can contaminate fresh produce.

- Prion

Prions are infectious agents made of proteins that are unique in that they have been linked to specific forms of neurodegenerative disease. Bovine spongiform encephalopathy (BSE, or so-called mad cow disease) is a prion disease in cattle that is related to variant Creutzfeldt-Jakob disease (vCJD) in humans. Consuming meat products that contain certain risk substances, such as brain tissue, is the most likely route of transmitting prion agents to humans.

- Chemicals

Of greatest health concern are naturally occurring toxins and environmental pollutants.

Naturally occurring toxins include mycotoxins, marine biotoxins, cyanogenic glycosides and toxins produced in poisonous mushrooms. Staple foods such as corn or grains can contain high levels of mycotoxins such as aflatoxins and ochratoxins produced by molds that grow on grains. Long-term exposure can affect the immune system and normal development, or cause cancer.

Persistent organic pollutants (POPs) are chemical compounds that accumulate in the environment and in the human body. Known examples are dioxins and polychlorinated biphenyls (PCBs), which are unwanted by-products of industrial processes and waste incineration. They are found in environments all over the world and accumulate in animal food chains. Dioxins are highly toxic and can cause reproductive and developmental problems, damage the immune system, interfere with hormones and cause cancer.

Heavy metals such as lead, cadmium, and mercury can cause nerve and kidney damage. The pollution of heavy metals in food is mainly realized through the pollution of water and soil.

Other chemical hazards in food include radioactive nucleotides that can be released into the environment from industry and civil or military nuclear operations, food allergens, drug residues, and other contaminants that are incorporated into food during processing.

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