Foodborne illness

Foodborne illness or food poisoning is caused by consumingfoodcontaminated with pathogenicbacteria, toxins, viruses, prionsor parasites. Such contamination usually arises from improper handling, preparation or storageof food. Foodborne illness can also be caused by adding pesticidesor medicinesto food, or by accidentally consuming naturally poisonous substances like poisonous mushroomsor reef fish. Contact between foodand pests, especially flies, rodentsand cockroaches, is a further cause of contamination of food.

Some common diseases are occasionally foodborne mainly through the water vector, even though they are usually transmitted by other routes. These include infections caused by Shigella, Hepatitis A, and the parasites Giardia lamblia and Cryptosporidium parvum.

The World Health Organizationdefines it as diseases, usually either infectious or toxic in nature, caused by agents that enter the body through the ingestion of food. Every person is at risk of foodborne illness[1].

Good hygienepractices before, during, and after food preparation can reduce the chances of contracting an illness.

Symptoms and mortality

Symptomstypically begin several hours after ingestionand depending on the agent involved, can include one or more of the following: nausea, abdominal pain, vomiting, diarrhea, fever, headacheor tiredness. In most cases the body is able to permanently recover after a short period of acutediscomfort and illness. However, foodborne illness can result in permanent health problems or even death, especially in babies, pregnantwomen(and their fetuses), elderlypeople, sickpeople and others with weak immune systems. Similarly, people with liverdisease are especially susceptible to infections from Vibrio vulnificus, which can be found in oysters.

Incubation period

The delay between consumption of a contaminated food and appearance of the first symptomsof illness is called the incubation period. This ranges from hours to days (and rarely months or even years), 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 rather than live bacteria.

During the incubation period, microbespass through the stomachinto the intestine, attach to the cellslining the intestinal walls, and begin to multiply there. Some types of microbes stay in the intestine, some produce a toxinthat is absorbed into the bloodstream, and some can directly invade the deeper body tissues. The symptoms produced depend on the type of microbe. [2]

Infectious dose

The infectious doseis 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].

Pathogenic agents

An early theory on the causes of food poisoning involved ptomaines, alkaloidsfound in decaying animal and vegetable matter. While some poisonous alkaloids are the cause of poisoning, the discovery of bacteria left the ptomaine theory obsolete.

Bacteria

Bacterialinfection is the most common cause of food poisoning. In the United Kingdomduring 2000the individual bacteria involved were as follows: Campylobacter jejuni 77.3%, Salmonella 20.9%, Escherichia coli O157:H7 1.4%, and 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 hoursafter 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
• Escherichia coli O157:H7 enterohemorrhagic (EHEC) which causes hemolytic-uremic syndrome
• Escherichia coli - enteroinvasive(EIEC)
• Escherichia coli - enteropathogenic(EPEC)
• Escherichia coli - enterotoxigenic(ETEC)
• Escherichia coli - enteroaggregative(EAEC or EAgEC)
• 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

Exotoxins

In addition to disease caused by direct bacterial infection, some foodborne illnesses are caused by exotoxinswhich are excretedby 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 botulismoccurs when the anaerobicbacterium Clostridium botulinum grows in improperly canned low-acid foods and produces a powerful paralytic toxin.

Preventing bacterial food poisoning

The prevention is mainly the role of the state, through the definition of strict rules of hygieneand a public serviceof veterinarysurvey of the food chain, from farmingto 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 HACCPand the "cold chain";
• power of control and of law enforcement of the veterinarians.

At home, the prevention mainly consists of:

• separating foods while preparing and storing to prevent cross contamination. (i.e. clean cutting boards, utensils, and hands after handling meat and before cutting vegetables, etc.) Wash hands and/or gloves before handling ready-to-eat foods.
• the respect of the food storage(hot foods hot and cold foods cold) and food preservationmethods (especially refrigeration), and checking the expiration date;
• washing the hands before preparing the meal and before eating;
• washing the fresh fruits and vegetables with clear water, especially when not cooked (e.g. fruits, salads)Scrub firm fruits and vegetables with a brush to clean.;
• washing the dishes after use;
• keeping the kitchen and cooking utensils clean.

Bacteria need warmth, moisture, food and timeto grow. The presence, or absence, of oxygen, salt, sugarand acidityare also important factors for growth. In the right conditions, one bacterium can multiply using binary fissionto become four millionin eight hours. Since bacteria can be neither smellednor seen, the best way to ensure that food is safe is to follow principles of good food hygiene. This includes not allowing rawor partially cooked food to touch dishes, utensils, handsor 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 pickledvegetables are traditional preserved foods.

The most frequent causes of bacterial foodborne illnesses are cross-contamination and inadequate temperaturecontrol. Therefore control of these two matters is especially important.

Thoroughly cookingfood 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 sporethat survives temperatures up to 100 °C (212 °F). Once cooked, hot foods should be kept at temperatures out of the danger zone. Temperatures above 63 °C (145 °F) stop microbial growth.

Cold foods should also be kept colder than the danger zone, below 5 °C (41 °F). However, Listeria monocytogenes and Yersinia enterocolitica can both grow at refrigeratortemperatures.

Viruses

Viralinfections 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.

• Norovirus(formerly Norwalk virus)
• Rotavirus
• Hepatitis Ais distinguished from other viral causes by its prolonged (2-6 week) incubation periodand 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

Parasites

Most foodborne parasitesare zoonoses.

Platyhelminthes:

• Taenia saginata
• Taenia solium
• Fasciola hepatica

See also: Tapeworm

Nematode:

• Ascaris lumbricoides
• Trichinella spiralis
• Trichuris trichiura

Protozoa:

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

Other:

• Anisakis sp.
• Cyclospora cayetanensis
• Diphyllobothrium sp.
• Eustrongylides sp.
• Nanophyetus sp.

Natural toxins

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

• Aflatoxin
• Alkaloid, see hemlock
• Ciguatera poisoning
• Grayanotoxin(honeyintoxication)
• Mushroomtoxins
• Phytohaemagglutinin(Red kidney beanpoisoning)
• Pyrrolizidine alkaloid
• Shellfish toxin, including Paralytic shellfish poisoning, Diarrhetic shellfish poisoning, Neurotoxic shellfish poisoning, Amnesic shellfish poisoningand Ciguatera fish poisoning
• Scombrotoxin
• Tetrodotoxin(Fugu fishpoisoning)

Other pathogenic agents

• Prions, resulting in Creutzfeldt-Jakob disease

Statistics

There are every year 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

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

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

Source:

• Food safety and foodborne illness, WHO

In France

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

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

The causes of the illness (toxic factor) are:

The causes of death by foodborne illness are:

Source:

• Report of the French sanitary agenciesINVS/Afssa (PDFfile, 192p, 660 KB, in French)
• Sumup of the report(PDFfile, 5p, 60 KB, in French)

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 multiplywhich 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 healthstaff from unexpected increases in laboratory results for certain strains of bacteria.

Political issues

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 1996Wishaw outbreak of E.coli O157 [6], which was a precursor to the establishment of the Food Standards Agencywhich, according to Tony Blairin the 1998white paper A Force for Change Cm 3830"would be powerful, open and dedicated to the interests of consumers". There remain questions, however, over the nature of any agency funded by a government which has not an insignificant say in staffing.

United States

In 2001, the Center for Science in the Public Interest (CSPI) petitioned the United States Department of Agricultureto require meat packers to remove spinal cordsbefore 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 Organizationproscriptions to lessen the risk of infection by variant Creutzfeldt-Jakob disease [7].

See also

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

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
• Safe Tables Our Priority (S.T.O.P.)de:Lebensmittelvergiftung

fr:intoxication alimentaire nl:Voedselvergiftiging ja:食中毒 zh-cn:食物中毒

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Foodborne+illness Wikipedia article Foodborne illness.