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Foodborne illness 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. There is a consensus in the public health community that regular hand-washing is one of the most effective defenses against the spread of foodborne 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. For foodborne illness caused by chemicals, see Food contaminants. Foodborne illness can also be caused by pesticides or medicines in food and naturally toxic substances such as poisonous mushrooms or reef fish. Bacteria__ Bacteria are a common cause of foodborne illness. In the United Kingdom during 2000, the individual bacteria involved were the following: Campylobacter jejuni 77.3%, Salmonella 20.9%, Escherichia coli O157:H7 1.4%, and all others less than 0.56%.[3] In the past, bacterial infections were thought to be more prevalent because few places had the capability to test for norovirus and no active surveillance was being done for this particular agent. Toxins from bacterial infections are delayed because the bacteria need time to multiply. As a result symptoms associated with intoxication are usually not seen until 12–72 hours or more after eating contaminated food. Usually the symptoms are seen the day after the food has been ingested and digested completely. However if the intoxication involves preformed toxins as is the case with Staphylococcal food poisoning, the symptoms appear within a few hours.[citation needed] Most common bacterial foodborne pathogens are: Campylobacter jejuni which can lead to secondary Guillain–Barré syndrome and periodontitis[4] Clostridium perfringens, the "cafeteria germ"[5] Salmonella spp. – its S. typhimurium infection is caused by consumption of eggs or poultry that are not adequately cooked or by other interactive human-animal pathogens[6][7][8] Salmonella Escherichia coli O157:H7 enterohemorrhagic (EHEC) which can cause hemolytic-uremic syndrome Other common bacterial foodborne pathogens are: 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 Staphylococcal enteritis 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 Enterotoxins__ In addition to disease caused by direct bacterial infection, some foodborne illnesses are caused by a enterotoxins (an exotoxin targeting the intestines). Enterotoxins can produce illness even when the microbes that produced them have been killed. Symptom appearance varies with the toxin but may be rapid on-set, as in the case of enterotoxins of Staphylococcus aureus in which symptoms appear in 1–6 hours.[9] This causes intense vomiting including or not including diarrhea (resulting in staphylococcal enteritis), and staphylococcal enterotoxins (most commonly Staphylococcal Enterotoxin A but also including Staphylococcal Enterotoxin B) are the most commonly reported enterotoxins although cases of poisoning are likely underestimated.[10] It occurs mainly in cooked and processed foods due to competition with other biota in raw foods, and humans are the main cause of contamination as a substantial percentage of humans are persistent carriers of S. aureus.[10] The CDC has estimated about 240,000 cases per year in the United States.[11] Clostridium botulinum Clostridium perfringens Bacillus cereus 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. Emerging foodborne pathogens__ Many foodborne illnesses remain poorly understood. Approximately 99.9% percent of outbreaks are caused by unknown sources.[citation needed] Aeromonas hydrophila, Aeromonas caviae, Aeromonas sobria Preventing bacterial food poisoning__ Proper storage and refrigeration of food help in the prevention of food poisoning Prevention is mainly the role of the state, through the definition of strict rules of hygiene and a public services of veterinary surveying of animal products in the food chain, from farming to the transformation industry and 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; enforcement of hygiene procedures such as HACCP and the "cold chain"; power of control and of law enforcement of veterinarians. In August 2006, the United States Food and Drug Administration approved Phage therapy which involves spraying meat with viruses that infect bacteria, and thus preventing infection. This has raised concerns, because without mandatory labelling consumers would not be aware that meat and poultry products have been treated with the spray.[12] At home, prevention mainly consists of good food safety practices. Many forms of bacterial poisoning can be prevented even if food is contaminated by cooking it sufficiently, and either eating it quickly or refrigerating it effectively[citation needed]. Many toxins, however, are not destroyed by heat treatment. Mycotoxins and alimentary mycotoxicoses__ The term alimentary mycotoxicoses refers to the effect of poisoning by Mycotoxins (The term 'mycotoxin' is usually reserved for the toxic chemical products produced by fungi that readily colonize crops) through food consumption. Mycotoxins sometimes have important effects on human and animal health. For example, an outbreak which occurred in the UK in 1960 caused the death of 100,000 turkeys which had consumed aflatoxin-contaminated peanut meal. In the USSR in World War II, 5,000 people died due to Alimentary Toxic Aleukia (ALA).[13] 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.[14][15] 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.[16] The official document can be found at FDA's website.[17][18] 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.[19][20][21] 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.[22] Citrinin Citreoviridin Cyclopiazonic acid Cytochalasins Ergot alkaloids / Ergopeptine alkaloids – Ergotamine 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.[23][24] For human and animal health, both the FDA and the EC have regulated the content levels of toxins in food and animal feed.[25][26] 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,[27] 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.[28] Oosporeine Patulin – Currently, this toxin has been advisably regulated on fruit products. The EC and the FDA have limited it to under 50 µg/kg for fruit juice and fruit nectar, while limits of 25 µg/kg for solid-contained fruit products and 10 µg/kg for baby foods were specified by the EC.[28][29] 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.[30] 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.[31][32] 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 irritation.[33][34][35] In 1993, the FDA issued a document for the content limits of DON in food and animal feed at an advisory level.[36] In 2003, US published a patent that is very promising for farmers to produce a trichothecene-resistant crop.[37] Zearalenone Zearalenols Viruses__ Viral infections make up perhaps one third of cases of food poisoning in developed countries. In the US, more than 50% of cases are viral and noroviruses are the most common foodborne illness, causing 57% of outbreaks in 2004. Foodborne viral infection are usually of intermediate (1–3 days) incubation period, causing illnesses which are self-limited in otherwise healthy individuals; they are similar to the bacterial forms described above. 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 results in jaundice, or yellowing of the skin, but rarely leads to chronic liver dysfunction. The virus has been found to cause infection due to the consumption of fresh-cut produce which has fecal contamination.[38][39] Hepatitis E Norovirus Rotavirus Rotavirus Parasites__ Most foodborne parasites are zoonoses. Platyhelminthes: Diphyllobothrium sp. Nanophyetus sp. Taenia saginata Taenia solium Fasciola hepatica See also: Tapeworm and Flatworm 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 Giardia lamblia Sarcocystis hominis Sarcocystis suihominis Toxoplasma gondii Natural toxins__ 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 defenses such as poisons and distasteful substances, for example capsaicin in chili peppers and pungent sulfur 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 alkaloids 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. Foxglove contains cardiac glycosides. Poisonous hemlock (conium) has medicinal uses. Other pathogenic agents__ Prions, resulting in Creutzfeldt–Jakob disease "Ptomaine poisoning"__ An early theory on the causes of food poisoning involved ptomaines (from Greek ptōma, "fall, fallen body, corpse"), alkaloids found in decaying animal and vegetable matter. While some alkaloids do cause poisoning, the discovery of bacteria left the ptomaine theory obsolete, though as recently as 1882 the Merck's Bulletin stated, "We name such products of bacterial origin ptomaines; and the special alkaloid produced by the comma bacillus is variously named Cadaverine, Putrescine, etc."[40] |
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