2.1 In the United States

In the United States , for 76 million foodborne illnesses (26,000 cases for 100,000 inhab.):

• 325,000 were hospitalised (111 for 100,000 inhab.);
• 5,000 people died (1.7 for 100,000 inhab.).

Source:

• Food safety and foodborne illness, WHO

2.2 In France

In France, for 750,000 cases (1,210 for 100,000 inhab.):

• 70,000 people consulted in the emergency department of an hospital (113 for for 100,000 inhab.);
• 113,000 people were hospitalised (24 for 100,000 inhab.);
• 400 people died (0.1 for 100,000 inhab.).

The causes of the illness (toxic factor) are:

Causes of foodborne illness in France

	Cause	cases per year
1	salmonella	~8,000 cases (13 for 100,000 inhab.)
2	campylobacter	~3,000 cases (4.8 for 100,000 inhab.)
3	parasite incl. toxoplasma	~500 cases (0.8 for 100,000 inhab.) ~400 cases (0.65 for 100,000 inhab.)
4	listeria	~300 cases (0.5 for 100,000 inhab.)
5	hepatitis A	~60 cas (0.1 for 100,000 inhab.)

The causes of death by foodborne illness are:

Causes of death by foodborne illness in France

	Cause	cases per an
1	salmonella	~300 cases (0.5 for 100,000 inhab.)
2	listeria	~80 cases (0.13 for 100,000 inhab.)
3	parasite	~37 cases (0.06 for 100,000 inhab.) ( toxoplasma in 95% of the cases)
4	campylobacter	~15 cases (0.02 for 100,000 inhab.)
5	hepatitis A	~2 cases (0.003 for 100,000 inhab.)

Source:

• Report of the french sanitary agencies INVS/Afssa ( PDF file, 192p, 660 KB, in French)
• Sumup of the report ( PDF file, 5p, 60 KB, in French)

3 Symptoms and mortality

Symptoms typically begin several hours after ingestion and depending on the agent involved, can include one or more of the following: nausea, abdominal pain, vomitting, diarrhea, fever, headache or tiredness. In most cases the body is able to permanently recover after a short period of acute discomfort and illness. However, foodborne illness can result in permanent health problems or even death, especially in babies, pregnant women (and their fetuses), elderly people, sick people and others with weak immune systems. Similarly, people with liver disease are especially susceptible to infections from Vibrio vulnificus, which can be found in oysters.

4 Incubation period

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 years), depending on the agent, and on how much was consumed.

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. [2]

5 Infectious dose

The infectious dose is the amount of agent that must be consumed to give rise to symptoms of foodborne illness. The infective dose varies according to the agent and consumer's age and health. In the case of Salmonella, as few as 15-20 cells may suffice [3].

6 Pathogenic agents

6.1 Bacteria

Bacterial infection is the most common cause of food poisoning. In the United Kingdom during 2000 the individual bacteria involved were as follows: Campylobacter jejuni 77.3%; Salmonella 20.9% and 1.4%, all others less than 0.1% [4].

Symptoms for bacterial infections are delayed because the bacteria need time to multiply. They are usually not seen until 12-36 hours after eating contaminated food.

Common bacterial foodborne pathogens are:

• Aeromonas hydrophila , Aeromonas caviae, Aeromonas sobria
• Bacillus cereus
• Brucella spp.
• Campylobacter jejuni which causes Guillain-Barré syndrome
• Corynebacterium ulcerans
• Coxiella burnetii or Q fever
• Crohn's disease
• enterohemorrhagic (EHEC) which causes hemolytic-uremic syndrome
• Escherichia coli - enteroinvasive (EIEC)
• Escherichia coli - enteropathogenic (EPEC)
• Escherichia coli - enterotoxigenic (ETEC)
• Listeria monocytogenes
• Plesiomonas shigelloides
• Salmonella spp.
• Shigella spp.
• Streptococcus
• Vibrio cholerae, including O1 and non-O1
• Vibrio parahaemolyticus
• Vibrio vulnificus
• Yersinia enterocolitica and Yersinia pseudotuberculosis

6.1.1 Exotoxins

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.

• Clostridium botulinum
• Clostridium perfringens
• Staphylococcus aureus

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 a powerful paralytic toxin.

6.1.2 Preventing bacterial food poisoning

The prevention is mainly the role of the State, through the definition of strict rules of hygiene and a public service of veterinary survey of the food chain, from farming to the transformation industry and the delivery (shops and restaurants). This regulation includes

• traceability: in a final product, it must be possible to know the origin of the ingredients (originating farm, identification of the harvesting or of the animal) and where and when it was processed; the origin of the illness can thus be tracked and solved (and possibly penalized), and the final products can be removed from the sale if a problem is detected;
• respect of hygiene procedures like HACCP and the "cold chain";
• power of control and of law enforcement of the veterinarians.

At home, the prevention mainly consists in:

• the respect of the food storage and food preservation methods (especially the cold), checking the use-by date;
• washing the hands before preparing the meal and before eating;
• washing the fresh vegetables with clear water, especially when not cooked (e.g. fruits, salads);
• washing the dishes after use;
• keeping the kitchen clean.

Bacteria need warmth, moisture, food and time to grow. The presence, or absence, of oxygen, salt, sugar and acidity are also important factors for growth. In the right conditions, one bacterium can multiply using binary fission to become four million in eight hours. Since bacteria can be neither smelled nor seen, the best way to ensure that food is safe is to follow principles of good food hygiene. This includes not allowing raw or partially cooked food to touch dishes, utensils, hands or work surfaces previously used to handle even properly cooked or ready to eat food.

High salt, high sugar or high acid levels keep bacteria from growing, which is why salted meats, jam, and pickled vegetables are traditional preserved foods.

The most frequent causes of bacterial foodborne illness is cross-contamination or inadequate temperature control. Therefore control of these two matters is especially important.

Thoroughly cooking food until it is piping hot, i.e. above 70°C (158°F) will quickly kill virtually all bacteria, parasites or viruses, except for Clostridium botulinum and Clostridium perfringens, which produces a heat-resistant spore that survives temperatures up to 100°C (212°F). Once cooked, hot foods should be kept hot - above 63°C (145°F) stops multiplication.

Cold foods should be kept cold, below 5°C (41°F). However, Listeria monocytogenes and Yersinia enterocolitica can both grow at refrigerator temperatures.

6.2 Viruses

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

• Norwalk virus
• Rotavirus
• 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.
• Hepatitis E

6.3 Parasites

Most foodborne parasites are zoonoses.

6.3.1 Cestoda

• Taenia saginata
• Taenia solium

See also: Tapeworm

6.3.2 Nematode

• Ascaris lumbricoides
• Trichinella spiralis
• Trichuris trichiura

6.3.3 Protozoa

• Cryptosporidium parvum
• Entamoeba histolytica
• Giardia lamblia
• Sarcocystis hominis
• Sarcocystis suihominis
• Toxoplasma gondii

6.3.4 Platyhelminths

• Fasciola hepatica

6.3.5 Other

• Acanthamoeba and other free-living amoebae
• Anisakis sp.
• Cyclospora cayetanensis
• Diphyllobothrium sp.
• Eustrongylides sp.
• Nanophyetus sp.

6.4 Natural toxins

In contrast several foods can naturally contain toxins that are not produced by bacteria and occur naturally in foods, these include:

• Aflatoxin
• Alkaloid, see Hemlock
• Ciguatera poisoning
• Grayanotoxin ( Honey intoxication)
• Mushroom toxin
• Phytohaemagglutinin (Red kidney bean poisoning)
• 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)

6.5 Other pathogenic agents

• Prions, resulting in Creutzfeldt-Jakob disease

7 Outbreaks

The vast majority of reported cases of foodborne illness occur as individual or sporadic cases. In most cases these originate, and occur, in the home. An outbreak occurs when two or more people suffer foodborne illness after consuming food from a contaminated batch.

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, some are identified by public health staff from unexpected increases in laboratory results for certain strains of bacteria.

8 Political issues

8.1 United Kingdom

Since the 1970s, key changes in UK food safety law have taken place following serious outbreaks of food poisoning. These included the death of 19 patients in the Stanley Royd Hospital outbreak [5]; and the death of 17 people in the 1996 Wishaw outbreak of E.coli O157 [6], which was a precursor to the establishment of the independent Food Standards Agency which is dedicated to the interests of consumers.

8.2 United States

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 State's violation of World Health Organization proscriptions to lessen the risk of infection by variant Creutzfeldt-Jakob disease [7]

9 See also

• HACCP
• List of infectious diseases
• United States Disease Control and Prevention

10 External links

• Foodborne diseases, emerging, WHO, Fact sheet N°124, revised January 2002
• Food safety and foodborne illness, WHO, Fact sheet N°237, revised January 2002
• UK Health protection Agency
• US PulseNet
• Nottingham Trent University Foodborne illness research data
• US CDC food poisoning guide

Nutrition Food science Infectious diseases

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