Foodborne illness

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Foodborne illness is any illness resulting from the consumption of food. Although foodborne illness is commonly called food poisoning, this is often a misnomer. True food poisoning occurs when a person ingests a contaminating chemical or a natural toxin, while most cases of foodborne illness are actually food infection caused by a variety of foodborne pathogenic bacteria, viruses, prions or parasites. Such contamination usually arises from improper handling, preparation, or food storage. Good hygiene practices before, during, and after food preparation can reduce the chances of contracting an illness. The action of monitoring food to ensure that it will not cause foodborne illness is known as food safety. Foodborne disease can also be caused by a large variety of toxins that affect the environment. Foodborne illness can also be caused by the presence of pesticides or medicines in food, or by unintentionally consuming naturally toxic substances like poisonous mushrooms or reef fish.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

The delay between consumption of a contaminated food and appearance of the first symptoms of illness is called the incubation period. This ranges from hours to days (and rarely months or even years, such as in the case of Listeriosis or Creutzfeldt-Jacob disease), depending on the agent, and on how much was consumed. If symptoms occur within 1–6 hours after eating the food, it suggests that it is caused by a bacterial toxin or a chemical rather than live bacteria.

During the incubation period, microbes pass through the stomach into the intestine, attach to the cells lining the intestinal walls, and begin to multiply there. Some types of microbes stay in the intestine, some produce a toxin that is absorbed into the bloodstream, and some can directly invade the deeper body tissues. The symptoms produced depend on the type of microbe.

Bacteria are a common cause of foodborne illness. Symptoms for bacterial infections are delayed because the bacteria need time to multiply. They are usually not seen until 12–72 hours or more after eating contaminated food.

In addition to disease caused by direct bacterial infection, some foodborne illnesses are caused by exotoxins which are excreted by the cell as the bacterium grows. Exotoxins can produce illness even when the microbes that produced them have been killed. Symptoms typically appear after 1–6 hours depending on the amount of toxin ingested.

Viral infections make up perhaps one third of cases of food poisoning in developed countries. Foodborne viral infection are usually of intermediate (1–3 days) incubation period, causing illnesses which are self-limited in otherwise healthy individuals, and are similar to the bacterial forms described above.

The infectious dose is the amount of agent that must be consumed to give rise to symptoms of foodborne illness, and varies according to the agent and the consumer’s age and overall health. In the case of Salmonella a relatively large inoculum of 1 million to 1 billion organisms are necessary to produce symptoms in healthy human volunteers, as Salmonellae are very sensitive to acid. An unusually high stomach pH level (low acidity) greatly reduces the number of bacteria required to cause symptoms by a factor of between 10 and 100.

In addition to disease caused by direct bacterial infection, some foodborne illnesses are caused by exotoxins which are excreted by the cell as the bacterium grows. Exotoxins can produce illness even when the microbes that produced them have been killed. Symptoms typically appear after 1–6 hours depending on the amount of toxin ingested.

For example Staphylococcus aureus produces a toxin that causes intense vomiting. The rare but potentially deadly disease botulism occurs when the anaerobic bacterium Clostridium botulinum grows in improperly canned low-acid foods and produces botulin, a powerful paralytic toxin.

Pseudoalteromonas tetraodonis, certain species of Pseudomonas and Vibrio, and some other bacteria, produce the lethal tetrodotoxin, which is present in the tissues of some living animal species rather than being a product of decomposition.

The term alimentary mycotoxicoses refers to the effect of poisoning by Mycotoxins through food consumption. Mycotoxins have prominently affected on human and animal health such as an outbreak which occurred in the UK in 1960 that caused the death of 100,000 turkeys which had consumed aflatoxin-contaminated peanut meal and the death of 5,000 human lives by Alimentary toxic aleukia (ALA) in the USSR in World War II.^[1] The common foodborne Mycotoxins include:

• Aflatoxins – originated from Aspergillus parasiticus and Aspergillus flavus. They are frequently found in tree nuts, peanuts, maize, sorghum and other oilseeds, including corn and cottonseeds. The pronounced forms of Aflatoxins are those of B1, B2, G1, and G2, amongst which Aflatoxin B1 predominantly targets the liver, which will result in necrosis, cirrhosis, and carcinoma.^{[2] [3]} In the US, the acceptable level of total aflatoxins in foods is less than 20 μg/kg, except for Aflatoxin M1 in milk, which should be less than 0.5 μg/kg.^[4] The official document can be found at FDA‘s website.^{[5] [6]}

• Altertoxins – are those of Alternariol (AOH), Alternariol methyl ether (AME), Altenuene (ALT), Altertoxin-1 (ATX-1), Tenuazonic acid (TeA) and Radicinin (RAD), originated from Alternaria spp. Some of the toxins can be present in sorghum, ragi, wheat and tomatoes.^{[7] [8] [9]} Some research has shown that the toxins can be easily cross-contaminated between grain commodities, suggesting that manufacturing and storage of grain commodities is a critical practice ^[10].
• Fumonisins – Crop corn can be easily contaminated by the fungi Fusarium moniliforme, and its Fumonisin B1 will cause Leukoencephalomalacia (LEM) in horses, Pulmonary edema syndrome (PES) in pigs, liver cancer in rats and Esophageal cancer in humans.^{[11] [12]} For human and animal health, both the FDA and the EC have regulated the content levels of toxins in food and animal feed.^{[13] [14]}
• Fumonisins – Crop corn can be easily contaminated by the fungi Fusarium moniliforme, and its Fumonisin B1 will cause Leukoencephalomalacia (LEM) in horses, Pulmonary edema syndrome (PES) in pigs, liver cancer in rats and esophageal cancer in humans.^{[11] [12]} For human and animal health, both the FDA and the EC have regulated the content levels of toxins in food and animal feed.^{[13] [14]}
• Trichothecenes – sourced from Cephalosporium, Fusarium, Myrothecium, Stachybotrys and Trichoderma. The toxins are usually found in molded maize, wheat, corn, peanuts and rice, or animal feed of hay and straw.^{[15] [16]} Four trichothecenes, T-2 toxin, HT-2 toxin, diacetoxyscirpenol (DAS) and deoxynivalenol (DON) have been most commonly encountered by humans and animals. The consequences of oral intake of, or dermal exposure to, the toxins will result in Alimentary toxic aleukia, neutropenia, aplastic anemia, thrombocytopenia and/or skin irritaion.^{[17] [18] [19]} In 1993, the FDA issued a document for the content limits of DON in food and animal feed at an advisory level.^[20] In 2003, US published a patent that is very promising for farmers to produce a trichothecene-resistant crop.^[21]

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Bacteria are a common cause of foodborne illness.

Most common bacterial foodborne pathogens are:

• Campylobacter jejuni
• Salmonella spp. – its S. Typhimurium infection is caused by consumption of eggs that are not adequately cooked or by other interactive human-animal pathogens ^{[1], [2], [3]}.
• Escherichia coli O157:H7
• Bacillus cereus
• Escherichia coli, other virulence properties, such as enteroinvasive (EIEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroaggregative (EAEC or EAgEC)
• Listeria monocytogenes
• Shigella spp.
• Staphylococcus aureus
• Streptococcus
• Vibrio cholerae, including O1 and non-O1
• Vibrio parahaemolyticus
• Vibrio vulnificus
• Yersinia enterocolitica and Yersinia pseudotuberculosis

Less common bacterial agents:

• Brucella spp.
• Corynebacterium ulcerans
• Coxiella burnetii or Q fever
• Plesiomonas shigelloides

• Clostridium botulinum
• Clostridium perfringens
• Staphylococcus aureus
• Bacillus cereus

• Aflatoxins

• Altertoxins
• Citrinin –

• Citreoviridin –

• Cyclopiazonic acid –

• Cytochalasins

• Ergot alkaloids / Ergopeptine alkaloids – Ergotamine

• Fumonisins –
• Fusaric acid –

• Fusarochromanone –

• Kojic acid – ?

• Lolitrem alkaloids –

• Moniliformin –

• 3-Nitropropionic acid –

• Nivalenol –

• Ochratoxins – In Australia, The Limit of Reporting (LOR) level for Ochratoxin A (OTA) analyses in 20th Australian Total Diet Survey was 1 µg/kg ^[4], whereas the EC restricts the content of OTA to 5 µg/kg in cereal commodities, 3 µg/kg in processed products and 10 µg/kg in dried vine fruits ^[5].

• Oosporeine –

• Patulin
• Phomopsins –

• Sporidesmin A –

• Sterigmatocystin –

• Tremorgenic mycotoxins – Five of them have been reported to be associated with molds found in fermented meats. These are Fumitremorgen B, Paxilline, Penitrem A, Verrucosidin, and Verruculogen ^[6].

• Trichothecenes
• Zearalenone –

• Zearalenols –

Much is still not known about foodborne illness. Approximately sixty percent of outbreaks are still caused by unknown sources.

• Aeromonas hydrophila, Aeromonas caviae, Aeromonas sobria

• Enterovirus
• Hepatitis A is distinguished from other viral causes by its prolonged (2–6 week) incubation period and its ability to spread beyond the stomach and intestines, into the liver. It often induces jaundice, or yellowing of the skin, and rarely leads to chronic liver dysfunction. The virus has been found to cause the infection due to the consumption of fresh-cut produce which has fecal contamination ^{[7], [8]}.
• Hepatitis E
• Norovirus
• Rotavirus

Most foodborne parasites are zoonoses.

Platyhelminthes:

• Diphyllobothrium sp.
• Nanophyetus sp.
• Taenia saginata
• Taenia solium
• Fasciola hepatica

Nematode:

• Anisakis sp.
• Ascaris lumbricoides
• Eustrongylides sp.
• Trichinella spiralis
• Trichuris trichiura

Protozoa:

• Acanthamoeba and other free-living amoebae
• Cryptosporidium parvum
• Cyclospora cayetanensis
• Entamoeba histolytica
• Giardia lamblia
• Sarcocystis hominis
• Sarcocystis suihominis
• Toxoplasma gondii

Several foods can naturally contain toxins, many of which are not produced by bacteria. Plants in particular may be toxic; animals which are naturally poisonous to eat are rare. In evolutionary terms, animals can escape being eaten by fleeing; plants can use only passive defences such as poisons and distasteful substances, for example capsaicin in chilis and pungent sulphur compounds in garlic and onions. Most animal poisons are not synthesised by the animal, but acquired by eating poisonous plants to which the animal is immune, or by bacterial action.

• Alkaloids
• Ciguatera poisoning
• Grayanotoxin (honey intoxication)
• Mushroom toxins
• Phytohaemagglutinin (red kidney bean poisoning; destroyed by boiling)
• Pyrrolizidine alkaloid
• Shellfish toxin, including paralytic shellfish poisoning, diarrhetic shellfish poisoning, neurotoxic shellfish poisoning, amnesic shellfish poisoning and ciguatera fish poisoning
• Scombrotoxin

• Tetrodotoxin (fugu fish poisoning)

Some plants contain substances which are toxic in large doses, but have therapeutic properties in appropriate dosages.

• The foxglove contains belladonna.
• Poisonous hemlock (conium) has medicinal uses.

• Prions, resulting in Creutzfeldt-Jakob disease

An early theory on the causes of food poisoning involved ptomaines, alkaloids found in decaying animal and vegetable matter. While some alkaloids do cause poisoning, the discovery of bacteria left the ptomaine theory obsolete and the word “ptomaine” is no longer used scientifically.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

In modern times, rapid globalization of food production and trade has increased the potential likelihood of food contamination. Many outbreaks of foodborne diseases that were once contained within a small community may now take place on global dimensions. Food safety authorities all over the world have acknowledged that ensuring food safety must not only be tackled at the national level but also through closer linkages among food safety authorities at the international level. This is important for exchanging routine information on food safety issues and to have rapid access to information in case of food safety emergencies.

It is difficult to estimate the global incidence of foodborne disease, but it has been reported that in the year 2000 about 2.1 million people died from diarrheal diseases. Many of these cases have been attributed to contamination of food and drinking water. Additionally, diarrhea is a major cause of malnutrition in infants and young children.

Even in industrialized countries, up to 30% of the population of people have been reported to suffer from foodborne diseases every year. In the U.S, around 76 million cases of foodborne diseases, which resulted in 325,000 hospitalizations and 5,000 deaths, are estimated to occur each year. Developing countries in particular, are worst affected by foodborne illnesses due to the presence of a wide range of dieases, including those caused by parasites. Foodborne illnesses can and did inflict serious and extensive harm on society. In 1994, an outbreak of salmonellosis due to contaminated ice cream occurred in the USA, affecting an estimated 224,000 persons. In 1988, an outbreak of hepatitis A, resulting from the consumption of contaminated clams, affected some 300,000 individuals in China.

Food contamination creates an enormous social and economic strain on societies. In the U.S., diseases caused by the major pathogens alone are estimated to cost up to US $35 billion annually (1997) in medical costs and lost productivity. The re-emergence of cholera in Peru in 1991 resulted in the loss of US $500 million in fish and fishery product exports that year.

Every year there are about 76 million foodborne illnesses in the United States (26,000 cases for 100,000 inhabitants), 2 million in the United Kingdom (3,400 cases for 100,000 inhabitants) and 750,000 in France (1,210 cases for 100,000 inhabitants).

In the United States, there are approximately 76 million foodborne illnesses (26,000 cases for 100,000 inhabitants):^[1]

• 325,000 were hospitalized (111 per 100,000 inhabitants)
• 5,000 people died (1.7 per 100,000 inhabitants)
• Major pathogens from food borne illness in the United States cost upwards of US $35 billion dollars in medical costs and lost productivity (1997)

In France, for 750,000 cases(1,210 per 100,000 inhabitants):

• 70,000 people consulted in the emergency department of an hospital (113 per 100,000 inhabitants);
• 113,000 people were hospitalized (24 per 100,000 inhabitants);
• 400 people died (0.9 per 100,000 inhabitants).

In Australia, there are an estimated 5.4 million cases of food-borne illness every year, causing:^[2]

• 18,000 hospitalizations
• 120 deaths
• 2.1 million lost days of work
• 1.2 million doctor consultations
• 300,000 prescriptions for antibiotics

Causes of foodborne illness in France^[3][4]

	Cause	Annual cases	Rate (per 100,000 inhabitants)
1	Salmonella	~8,000 cases	13
2	Campylobacter	~3,000 cases	4.8
3	Parasites incl. Toxoplasma	~500 cases ~400 cases	0.8 0.65
4	Listeria	~300 cases	0.5
5	Hepatitis A	~60 cases	0.1

Causes of death by foodborne illness in France

	Cause	Annual	Rate (per 100,000 inhabitants)
1	Salmonella	~300 cases	0.5
2	Listeria	~80 cases	0.13
3	Parasites	~37 cases	0.06 (95% due to toxoplasma)
4	Campylobacter	~15 cases	0.02
5	Hepatitis A	~2 cases	0.003

The vast majority of reported cases of foodborne illness occur as individual or sporadic cases. The origin of most sporadic cases is undetermined. In the United States, where people eat outside the home frequently, most outbreaks (58%) originate from commercial food facilities (2004 FoodNet data). An outbreak is defined as occurring when two or more people experience similar illness after consuming food from a common source.

Often, a combination of events contributes to an outbreak, for example, food might be left at room temperature for many hours, allowing bacteria to multiply which is compounded by inadequate cooking which results in a failure to kill the dangerously elevated bacterial levels.

Outbreaks are usually identified when those affected know each other. However, more and more, outbreaks are identified by public health staff from unexpected increases in laboratory results for certain strains of bacteria. Outbreak detection and investigation in the United States is primarily handled by local health jurisdictions and is inconsistent from district to district. It is estimated that 1–2% of outbreaks are detected.

In the UK serious outbreaks of foodborne illness since the 1970s prompted key changes in UK food safety law. These included the death of 19 patients in the Stanley Royd Hospital outbreak ^[5] and the bovine spongiform encephalopathy (BSE, mad cow disease) outbreak identified in the 1980s. The death of 17 people in the 1996 Wishaw outbreak of E. coli O157 was a precursor to the establishment of the Food Standards Agency which, according to Tony Blair in the 1998 white paper A Force for Change Cm 3830 “would be powerful, open and dedicated to the interests of consumers”.

In 2001, the Center for Science in the Public Interest (CSPI) petitioned the United States Department of Agriculture to require meat packers to remove spinal cords before processing cattle carcasses for human consumption, a measure designed to lessen the risk of infection by variant Creutzfeldt-Jakob disease. The petition was supported by the American Public Health Association, the Consumer Federation of America, the Government Accountability Project, the National Consumers League, and Safe Tables Our Priority. This was opposed by the National Cattlemen’s Beef Association, the National Renderers Association, the National Meat Association, the Pork Producers Council, sheep raisers, milk producers, the Turkey Federation, and eight other organizations from the animal-derived food industry. This was part of a larger controversy regarding the United States’ violation of World Health Organization proscriptions to lessen the risk of infection by variant Creutzfeldt-Jakob disease.

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• Campylobacter jejuni which can lead to secondary Guillain-Barré syndrome and periodontitis.^[1]
• Escherichia coli O157:H7 enterohemorrhagic (EHEC) which causes hemolytic-uremic syndrome.

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