Food may be accidentally or deliberately contaminated by microbiological, chemical or physical hazards. In contrast to microbiologically caused foodborne illness, the link between exposure and effect of chemical hazards in foods is usually complicated by cumulative low doses and the delay between exposure and the onset of symptoms. Chemical hazards include environmental contaminants, food ingredients (such as iodine), heavy metals, mycotoxins, natural toxins, improper storage, processing contaminants, and veterinary medicines. Incidents have occurred because of poor harvesting or storage of grain, use of banned veterinary products, industrial discharges, human error and deliberate adulteration and fraud.

Definition of an incident 
An "incident" of chemical food contamination may be defined as an episodic occurrence of adverse health effects in humans (or animals that might be consumed by humans) following high exposure to particular chemicals, or instances where episodically high concentrations of chemical hazards were detected in the food chain and traced back to a particular event.

Socio-economic impacts 
Information on the impacts of these incidents is fragmentary and unsystematic, ranging from thousands of dollars to meet the cost of monitoring analysis, to many millions of dollars due to court prosecutions, bankruptcy, product disposal, compensation for revenue loss, damage to brand or reputation, or loss of life.

List of notable incidents

Ancient times
 Roman Empire – There is speculation that the Romans, in particular the elite, suffered severe chronic lead poisoning due to the ubiquity of lead in e.g. lined pots in which acidic foodstuffs were boiled, over and above any mere exposure to lead in water pipes. They also used sugar of lead to sweeten their wines.

Middle Ages
 Europe - numerous incidents of human poisoning due to the consumption of rye bread made from grain infected with ergot fungi

19th century
 1850s – Swill milk scandal in New York
 1857 – adulteration of bread with alum in London, causing rickets.
 1857 – Esing Bakery incident: poisoning of bread with arsenic in Hong Kong targeting the colonial community.
 1858 – sweets poisoned with arsenic in Bradford, England.

1900 to 1949
 1900 - 1900 English beer poisoning - Beer contaminated with arsenic. Traced to sugar manufactured with sulphuric acid that was naturally contaminated with arsenic from Spanish pyrites. An epidemic of 6070 cases in London, including 70 deaths
 1910–45 – Cadmium from mining waste contaminated rice irrigation water in Japan. Illness known as itai-itai disease affected more than 20% of women aged over 50 years
 1920 – In South Africa, 80 people suffered poisoning from eating bread contaminated with naturally occurring pyrrolizidine alkaloids.
 1900s–49 – Agene process; Severe and widespread neurological disorders due to bread flour bleached with agene, a process no longer in use. The denatured protein in the treated flour is toxic and causes a condition of hysteria in dogs eating biscuits made from the flour.
 1930s – An epidemic of OPIDN organophosphate poisoning occurred during the 1930s Prohibition Era. Thousands of men in the American South and Midwest developed arm and leg weakness and pain after drinking a "medicinal" alcohol substitute called "Ginger Jake". The substance contained an adulterated Jamaican ginger extract, which was contaminated with tri-ortho-cresyl phosphate (TOCP). The contamination resulted in partially reversible neurologic damage. The damage resulted in the limping "Jake Leg" or "Jake Walk", which were terms frequently used in the blues music of the period. Europe experienced outbreaks of TOCP poisoning from contaminated abortifacients. Morocco experienced outbreaks of TOCP poisoning from contaminated cooking oil.
 1942 – Prisoners at the Vapniarka concentration camp, in present day Ukraine, were fed a diet containing significant quantities of Lathyrus sativus, a species of pea that was normally used to feed livestock. A team of doctors among the inmates, led by Dr. Arthur Kessler of Cernăuţi, reached the conclusion that the disease presented all the symptoms of lathyrism, a spastic paralysis caused by the oxalyldiaminopropionic acid present in the pea fodder. Within a few weeks, the first symptoms of the disease appeared, affecting the bone marrow of prisoners and causing paralysis. By January 1943, hundreds of prisoners were suffering from lathyrism.

1950 to 2000
 1951 - 1951 Pont-Saint-Esprit mass poisoning in France, probably caused by ergot.
 1950s – Minamata disease: Mercury poisoning in fish in Japan, contaminated by industrial discharge. By 2010 more than 14,000 victims had received financial compensation.
 1955 – Morinaga Milk arsenic poisoning incident: Arsenic in milk powder in Japan. An industrial grade of monosodium phosphate additive which inadvertently contained 5–8% arsenic, was added to milk fed to infants. Over 600 died, and over 6,000 people suffered health effects such as severe intellectual disability. Those health effects have continued in the remaining survivors today.
 1957 – In the United States, millions of chickens died after eating dioxin-contaminated feed, and 300,000 more were destroyed to prevent consumption. It was later discovered that the feed was made with contaminated tallow, eventually traced to the use of trimmings from pentachlorophenol-treated cow hides at rendering plants.
 1959 – Moroccan oil poisoning disaster: several thousand people in Meknes suffer flaccid paralysis caused by deliberate contamination of cooking oil with jet engine lubricating oil containing tricresyl phosphate got as surplus from a US airbase at Nouaceur.
 1965 - Mass poisoning resulting from contamination of flour with 4,4'-methylenedianiline in Epping, Essex, United Kingdom
 1968 - Yushō disease; mass poisoning resulting from rice bran oil contaminated with polychlorinated biphenyls in Kyūshū, Japan
 1971 – 1971 Iraq poison grain disaster: 100 to 400 died of mercury poisoning by eating seeds intended for planting and treated with mercury as a fungicide.
 1973 – Michigan PBB contamination incident: Widespread poisoning of people in Michigan by meat from cattle fed feed contaminated with polybrominated biphenyl flame retardant.
 1974–1976 – Afghanistan: widespread poisoning (an estimated 7800 people affected with hepatic veno-occlusive disease (liver damage) and about 1600 deaths) was attributed to wheat contaminated with weed seeds known as charmac (Heliotropium popovii. H Riedl) that contain pyrrolizidine alkaloids.
 1976 – Seveso dioxin contamination in Italy.
 1979 – in central Taiwan, Over 2,000 individuals were affected by dioxin-contaminated cooking oil in what came to be called Yu-Cheng.
 1981 – Spanish toxic oil syndrome. Thousands permanently damaged by eating industrial colza oil denatured with aniline and sold as olive oil. There was strong suspicion that the cause was in fact insecticide in Spanish tomatoes, and that official agencies actively supported the contaminated oil position, suppressing evidence contradicting it.
 1984 – Rajneeshee bioterror attack: Cult members of a small town in Oregon spiked the salad bars of ten local restaurants with salmonella in an attempt to incapacitate voters ahead of an upcoming election. About 750 people contracted salmonellosis.
 1984/85 - hamburger thyrotoxicosis among residents of southwestern Minnesota and adjacent areas of South Dakota and Iowa.
 1985 - Aldicarb pesticide residue present in watermelons grown in California caused an outbreak of pesticide food poisoning which affected over 2,000 people, and lead to a temporary ban on watermelon sales.
 1985 – Adulteration of Austrian wines with diethylene glycol.
 1986 – Adulteration of Italian wines with ethylene glycol killed more than 18 people.
 1987 – Beech-Nut Nutrition Corporation paid $2.2 million, then the largest fine issued, for violating the Federal Food, Drug, and Cosmetic Act by selling artificially flavored sugar water as apple juice. John F. Lavery, the company's vice president for operations was convicted in criminal court and sentenced to a year and a day in jail; Niels L. Hoyvald, the president of the company, also convicted, served six months of community service. Each of them also paid a $100,000 fine.
 1989 – Milk contamination with dioxin in Belgium
 1993 – Jack in the Box E. coli outbreak - Escherichia coli O157:H7 bacterium originating from contaminated beef patties killed four children and infected 732 people across four states in the United States.
 1994 – Ground paprika in Hungary was found to be adulterated with lead oxide, causing deaths of several people, while dozens of others became sick.
 1996 - Odwalla E. coli outbreak - apple juice made using blemished fruit contaminated with E. coli bacterium, which ultimately killed one and sickened 66 people.
 1996 - Japan E. coli O157:H7 outbreak in Osaka, Japan schools, with over 7,000 students affected. Linked to white radish sprouts.
 1996 - Wishaw, Scotland E. coli outbreak. Butchers John M. Barr & Son sold contaminated meat products to several events. Deadliest outbreak of the 0157 strain, with 21 people killed.
 1998 – Delhi oil poisoning. In New Delhi, India, edible mustard oil adulterated with Argemone mexicana seed oil caused epidemic dropsy in thousands of people, because Argemone mexicana seed oil contains the toxic alkaloids sanguinarine and dihydrosanguinarine. Over 60 people died and more than 3000 were hospitalized in the 1998 incident. Similar incidents have occurred in India since that time: in 2000 at Gwalior (2000), and in 2002 at Kannauj, and in 2005 at Lucknow.
 1998 – In Germany and the Netherlands, meat and milk were found with elevated dioxin concentrations. The dioxin was traced to citrus pulp from Brazil that had been neutralized with lime contaminated with dioxin. 92,000 tons of citrus pulp was discarded. The citrus pulp market collapsed in some European countries. A tolerance level for dioxins in citrus pulp was set by the European Commission.
 1999 – In Belgium, animal feed contaminated with dioxins and polychlorinated biphenyls affected more than 2500 poultry and pig farms. This incident led to the formation of the Belgium Federal Food Safety Agency. The loss to the Belgium economy was estimated at €1500-€2000M.
 1999–2000 – In Afghanistan, there were an estimated 400 cases of liver damage and over 100 deaths due to pyrrolizidine alkaloid poisoning. The food source was not identified.

2001 to 2010
 2001 – Spanish olive pomace oil was contaminated with polycyclic aromatic hydrocarbons. Contaminated product was recalled.
 2002 – In Northern Ireland, nitrofurans were detected in 5 (of 45) samples of chicken imported from Thailand and Brazil. The product was withdrawn and destroyed.
 2002 – In the UK, nitrofurans were detected in 16 (of 77) samples of prawns and shrimps imported from SE Asia. Affected batches were withdrawn and destroyed.
 2002 –  In the UK and Canada, the banned antibiotic, chloramphenicol, was found in honey from China
 2002 - In China, 42 people, mostly schoolchildren, died after eating poisoned food from a breakfast shop in the city of Nanjing. More than 300 were also seriously injured. The authority later tried and executed a man who was said to have deliberately poisoned his rival shop's food. 
 2003 – Dioxins were found in animal feed that was contaminated with bakery waste that had been dried by firing with waste wood.
 2003 – The banned veterinary antibiotic nitrofurans were found in chicken from Portugal. Poultry from 43 farms was destroyed. Nitrofurans are banned from food because of concerns including a possible increased risk of cancer in humans through long-term consumption.
 2004 – Organic free-range chicken was found to contain traces of the banned veterinary drug, nitrofuran. Up to 23 tonnes of affected chicken, originating from a farm in Northern Ireland, was distributed to supermarkets across the UK resulting in a voluntary product recall and consumer warnings.
 2004 – The Canadian Food Inspection Agency (CFIA) detected chloramphenicol in honey labelled as product of Canada. Chloramphenicol is banned for use in food-producing animals, including honey bees, in Canada as well as in a number of other countries. The Canadian Food Inspection Agency (CFIA) informed Health Canada that five lots of honey labelled as "Product of Canada" were distributed in British Columbia and were found to contain residues of the banned drug chloramphenicol. A voluntary food recall occurred.
 2004 – New Zealand soy milk manufactured with added kelp contained toxic levels of iodine. Consumption of this product was linked to five cases of thyrotoxicosis. The manufacturer ceased production and re-formulated the product line.
 2004 – New Zealand cornflour and cornflour-containing products were contaminated with lead, thought to have occurred as a result of bulk shipping of corn (maize) contaminated by previous cargo in the same storage. Affected product was distributed in New Zealand, Fiji and Australia. Four products were recalled.
 2004 – Aflatoxin-contaminated maize in Kenya resulted in 317 cases of hepatic failure and 125 deaths.
 2004 – EHEC O104:H4 in South Korea, researchers pointed at contaminated hamburgers as a possible cause.
 2005 – Worcester sauce in the UK was found to contain the banned food colouring, Sudan I dye, that was traced to imported adulterated chilli powder. 576 food products were recalled.
 2005 – Farmed salmon in British Columbia, Canada was found to contain the banned fungicide malachite green. 54 tonnes of fish was recalled. The incident resulted in an estimated $2.4-13M (USD) lost revenue.
 2006 – Pork, in China, containing clenbuterol when pigs were illegally fed the banned chemical to enhance fat burning and muscle growth, affected over 300 persons.
 2007 – Pet food recalls occurred in North America, Europe, and South Africa as a result of Chinese protein export contamination using melamine as an adulterant.
 2008 – Baby milk scandal, in China. 300,000 babies affected, 51,900 hospitalisations and 6 infant deaths. Lost revenue compensation~$30M, bankruptcy, trade restrictions imposed by 68 countries, 60 or more arrests, executions, prison sentences, and loss of consumer confidence. Melamine from the contaminated protein worked into the food chain a year later
 2008 – Wheat flour contaminated with naturally-occurring pyrrolizidine alkaloids is thought to be the cause of 38 cases of hepatic veno-occlusive disease including 4 deaths in Afghanistan
 2008 – Irish pork crisis of 2008: Irish pork and pork products exported to 23 countries was traced and much was recalled when animal feed was contaminated with dioxins in the feed drying process. The cost of cattle and pig culling exceeded €4M, compensation for lost revenue was estimated to be €200M.
 2008 – In Italy, it was discovered that additives included substances like sulfuric acid and hydrochloric acid had been used to dilute wines.
 2008 – In Italy, dioxin was found in buffalo milk from farms in Caserta. The probable source was groundwater contamination from illegal waste dumping in the Triangle of death (Italy).
 2008 United States salmonellosis outbreak - an outbreak of salmonellosis across multiple U.S. states linked to jalapeño peppers imported from Mexico.
 2009 – Pork, in China, containing the banned chemical clenbuterol when pigs were illegally fed it to enhance fat burning and muscle growth. 70 persons were hospitalised in Guangzhou with stomach pains and diarrhoea after eating contaminated pig organs
 2009 – Hola Pops from Mexico contaminated with lead
 2009 – Bonsoy-brand Soymilk in Australia, enriched with 'Kombu' seaweed resulted in high levels of iodine, and 48 cases of thyroid problems. The product was voluntarily recalled and a settlement of 25 million AUS$ later reached with the victims.
 2010 – Snakes in China were contaminated with clenbuterol when fed frogs treated with clenbuterol. 13 people were hospitalised after eating contaminated snake. There were 113 prosecutions in 2011 relating to clenbuterol, with sentences ranging from three years imprisonment to death.

2011 to 2022
 2011 United States listeriosis outbreak - a widespread outbreak of Listeria monocytogenes food poisoning across 28 US states that resulted from contaminated cantaloupes linked to Jensen Farms of Holly, Colorado. As of the final report on 27 August 2012, there were 33 deaths and 147 total confirmed cases since the beginning of the first recorded case on 31 July 2011.
 2011 – contaminated illegal alcohol in West Bengal resulted in an estimated 126 deaths. The alcohol may have contained ammonium nitrate and/or methanol.
 2011 – German E. coli O104:H4 outbreak was caused by EHEC O104:H4 contaminated fenugreek seeds imported from Egypt in 2009 and 2010, from which sprouts were grown in Germany.
 2011 – Vinegar from China contaminated with ethylene glycol when stored in tanks that previously contained antifreeze, led to 11 deaths and an estimated 120 cases of illness.
 2011 – Meat, eggs and egg products in Germany contaminated from animal feed containing fat contaminated with dioxins. 4,700 German farms affected. 8,000 hens and hundreds of pigs were culled. Imports from Germany to China were banned.
 2012 – More than a quarter of a million chicken eggs were recalled in Germany after in-house testing discovered "excessive levels" of the poisonous chemical, dioxin.
 2012, June – A Brazilian housewife discovered an apparently used condom at the bottom of a can of Knorr tomato paste. Unilever was fined £3,100 ($4,800) by the Supreme Federal Court. She was awarded £1,110 ($1,700) for moral damages, as she and her family had consumed a meal prepared with the paste.
 2012, July – Around 1 million pots of herbs had to be destroyed in North Rhine-Westphalia after treatment with an apparently organic plant growth strengthener was found to contain DDAC (didecyl-dimethylammonium chloride) which resulted in contamination levels above the EU MRL of 0.01 mg/kg. This has resulted in significant additional costs to member states across the EU who put in place a monitoring programme until February 2013 for DDAC and other quaternary ammonium compounds across a wide range of commodity groups. 
 2012, August to September – Multiple American Licorice Company black licorice products recalled due to high lead levels in the products.  Consuming a bag of product could give children lead levels as high as  double the amount regulators consider actionable.
 2012, October - frozen Chinese strawberries contaminated with norovirus infected over 11,000 children in Germany.
 2013, January – It was disclosed that horse meat contaminated beef burgers had been on sale in Britain and Ireland. Two companies, ABP Food Group and Liffey Meats, had supplied various supermarkets with contaminated own brand burgers from their meat factories in the UK and Ireland.
 2013, February – In Germany 200 farms are suspected of selling eggs as "organic" but not adhering to the conditions required for the label.
 2013, March – A batch of 1800 almond cakes with butter cream and butterscotch from the Swedish supplier, Almondy, on its way to the IKEA store in Shanghai were found by Chinese authorities to have a too high amount of coliform bacteria and were subsequently destroyed.
 2013, March – A vegetable seller in western Germany, Rhine Main, realized that the lettuce he had been selling throughout the day contained rat poison. The poison appears as small blue kernels.
 2013 aflatoxin contamination – Contamination with aflatoxins results in a milk recall in Europe and a dog food recall in the United States in February and March.
 2013, May – A Chinese crime ring was found to have passed off rat, mink, and small mammal meat as mutton for more than  in Shanghai and Jiangsu province markets.
 2013, May – Halal Lamb Burgers contained samples of Pork DNA, affected 19 schools in Leicester, UK.
 2013, July – Bihar school meal poisoning incident, India.
 2013, October – 2013 Taiwan food scandal
 2014, September – 2014 Taiwan food scandal
 2015, January - Mozambique funeral beer poisoning, Beer served at a funeral in Mozambique was contaminated with bongkrekic acid, resulting in 75 deaths and more than 230 people falling ill.
 2015, April – Contaminated milk tea resulted in the deaths of two individuals and affected another in Sampaloc, Manila, the cause of which was determined to have been oxalic acid being deliberately laced at more than the lethal oral dose.
 2015, April – In the US, Blue Bell Creameries recalled eight million US gallons (thirty million L) of ice cream after an outbreak of listeria at one of their production facilities led to ten hospitalizations and three deaths.
 2015, June - In India and Nepal, lead contamination in Nestlé's Maggi brand instant noodles made headlines in India, with some seven times the allowed limit; several Indian states banned the product, as did Nepal.
 2015, July – 2015 Caraga candy poisonings in the Philippines
 2015, November–December – United States E. coli outbreak
 2016, February–March – Mars Chocolates contamination incident, in which plastic found in candy bars lead to a recall affecting 55 countries.
 2016, April–May, CRF Frozen Foods recalled over 400 frozen food products due to listeria outbreak that sickened 8 people.
 2016, April–May - 2016 Punjab sweet poisoning, confectioneries contaminated with the toxic insecticide chlorfenapyr caused 33 deaths.
 2017 fipronil eggs contamination in Europe and Asia
 2017-18 South African listeriosis outbreak, linked to contaminated polony. Remains the largest listeriosis outbreak on record.
 2018 Australian rockmelon listeriosis outbreak, listeriosis traced to rockmelon (also known as cantaloupe) grown in New South Wales, Australia.
 2018 Australian strawberry contamination, where strawberries were found to contain needles.
 2019 - Dioxin contamination of eggs in Tropodo, Indonesia. The dioxin is produced by the burning of plastic as fuel for the local tofu industry.
 2019 - An Internet trend in the United States saw individuals filming themselves opening containers of ice cream from shelves, licking the ice cream, and returning the container to the shelf. One man from Texas was convicted of misdemeanor criminal mischief after filming himself licking Blue Bell ice cream in a Walmart.
 2020 sesame seeds contamination Sesame seeds sold in Europe, originating in India, contaminated by ethylene oxide.
 2020 - 10 people died and 16 were left disabled after an ethylene glycol contamination in brazilian craft beers produced in Minas Gerais. Made by Backer, the "Belorizontina" branded beers first showed issues in January of 2019, but this information wasn't presented to health officials. When inspected, the production was shown to be irregular, with a leaking tank and spots of contamination. Their beers were recalled, with 79.481,34 liters of the drink being apprehended in Backer's production line and also markets. Of those, 56.659 bottles were considered too risky for human consumption. Although Anvisa prohibited Backer from operating in 2020 and they were sued almost R$12,000,000 (around U$2.503.390 in 2022), they are allowed to produce again since April 2022, while their victims are still suffering from the poisoning and fighting for justice.   In the 21st of July 2023, Backer settled with the Ministério Público and will have to pay R$500,000 ($104.308 in 2023) to each victim (at the moment, only 9 of them are officially recognized) plus $150000 (U$31.292,38) to each of their first-degree relatives, the same amount of money from the victim's last paycheck and their medical treatment, plus for any job or opportunity lost because of the incident. Some relatives from the people that passed away say they weren't included in the restitution, because their family members' death happened before the investigation started. To G1, the widow of a 63 years old man affirmed he was hospitalized and passed away in February:; "I have 3 reports, including one from the Civil Police, the coroner, I have his necropsy reports, I have a report from the medical board, saying 'We can confirm that Mr. José Osvaldo de Faria was intoxicated by the poison diethylene glycol produced by the Backer Beer'".
 2020 - In Jixi city, China nine people died after eating homemade fermented corn noodles contaminated with bongkrekic acid.
 2021 - Butterball recalled over 14,000 lbs of turkey meat due to suspected plastic contamination.
 2022 - Abbott Nutrition recalled Similac baby formula after the death of an infant from Cronobacter sakazakii. The recall caused significant shortages in baby formula across the United States.
 2022 - At least 40 dogs died in Brazil after consuming Bassar produced snacks for dental care that were also sold under the Petz brand. The snacks were contaminated with ethylene glycol, probably originating from contamined propylene glycol. All products made by Bassar were recalled on the 7th of September.

2023 to present

Responses
In 2013, Professor Chris Elliott, Professor of Food Safety and Director of the Institute for Global Food Security at Queen's University Belfast, was asked by the UK's Secretaries of State for Defra and Health to undertake a review of the weaknesses within UK food supply networks and to suggest measures which might be taken to address these issues. After an interim report was published in December 2013, his final report was published in July 2014, recommending that the UK adopt a National Food Crime Prevention Framework.

His 8 recommendations, or "eight pillars of food integrity", provided for:
 maintaining customer confidence in food as a chief priority
 a "zero tolerance" approach to food fraud or food crime
 a focus on intelligence gathering
 the role of laboratory services
 the value of audit and assurance regimes
 targeted government support for the integrity and assurance of food supply networks
 leadership, and
 crisis management in response to any serious food safety or food crime incident.

See also
 List of foodborne illness outbreaks by death toll
 List of foodborne illness outbreaks
 Gutter oil
 List of medicine contamination incidents
 List of man-made mass chronic poisoning incidents
 Identity preservation

References 

Food Contamination Incidents
Food contamination