109 Fun Facts About Food Safety

Food-safety agencies define the bacterial 'danger zone' as roughly what temperature range?

4 to 60 °C (40 to 140 °F) is where germs multiply quickest, which is why big batches of leftovers go into shallow containers so they cool through it fast.

Under US guidance, perishable food left out at room temperature for more than how many hours should be thrown out?

Two hours is the limit, but on a day above 32 °C (90 °F), like a summer picnic or inside a hot car, perishables should be refrigerated within one hour.

After a power cut, what does US guidance say shows thawing freezer food is safe to refreeze?

It still has ice crystals, or sits at 4 °C (40 °F) or below, so it can be refrozen, but looks, smell and taste cannot tell you whether thawed food is safe.

Why does US food-safety guidance say to skip rinsing raw chicken?

It splashes germs onto nearby surfaces, so a rinse meant to clean the chicken raises the risk instead, while cooking it to a safe internal temperature kills the germs.

Why must ground beef reach 160 °F, when a steak is safe at 145 °F?

Grinding spreads surface germs inside, while bacteria on an intact steak mostly stay on the outside, and US inspectors treat blade-tenderized steaks as a risk for the same reason.

Where should the tip of a meat thermometer probe go?

The thickest part, not touching bone, gives the true reading, and a thermometer beats judging by eye, since ground beef can look brown and done before it is safely cooked.

WHO estimates contaminated food made roughly what share of the world's people ill in 2021?

1 in 9 people, some 866 million, fell ill from contaminated food in 2021, and the lost productivity alone cost an estimated US$310 billion.

The CDC's 2011 estimate put yearly foodborne illnesses in the US at roughly how many?

48 million is about 1 in 6 Americans a year, yet only about 9.4 million of those cases could be pinned on 31 known pathogens, and unspecified agents account for the rest.

Norovirus causes roughly what share of US foodborne illnesses traced to a known pathogen?

About 58% of those illnesses are norovirus, and outbreaks most often start when an infected food worker handles ready-to-eat food during preparation.

Norovirus takes its name from an outbreak in 1968 at an elementary school in which Ohio town?

Norwalk's outbreak samples were saved, and in 1972 Albert Kapikian finally spotted the tiny virus in them using an electron microscope.

Why do alcohol-based hand sanitisers tend not to work against norovirus?

The virus has no lipid envelope for alcohol to break apart, which is why handwashing with soap and water beats sanitiser gel during norovirus outbreaks.

Which two categories of food are most often implicated in norovirus outbreaks?

Shellfish and salad ingredients often reach the plate uncooked, so no heating step kills the virus before it is eaten.

In Rutgers' 2016 test of the five-second rule, which dropped food picked up the most bacteria?

Watermelon, the wettest food tested, picked up the most, and some bacteria crossed over in under a second, disproving the five-second rule.

A 2011 E. coli outbreak in Germany that killed dozens was traced to which food?

Sprouts carried the strain, and unusually, 88% of patients who developed the kidney-damaging haemolytic-uraemic syndrome were adults rather than young children.

Which pets did the US ban from sale below four inches long in 1975, to curb Salmonella in children?

Turtles with shells under four inches were targeted because small children put them in their mouths, and the ban cut turtle-linked Salmonella cases among children.

Which food spread Salmonella to 714 people in 46 US states in 2008–09, killing nine?

Peanut butter and paste from one company went into so many other foods, from cookies to ice cream, that the recall covered thousands of products.

Why must eggs be refrigerated in the US but not in much of Europe?

US producers wash them, eroding the cuticle, a natural barrier on the shell, which is why EU rules ban washing Class A eggs to keep bacteria from getting inside.

Which cattle disease led the EU to ban exports of British beef in 1996?

Mad cow disease had just been linked to new cases of Creutzfeldt-Jakob disease, a fatal human brain illness, so all British beef exports were halted.

Pregnant women are advised to avoid soft cheeses such as Brie and feta because of which bacterium?

Listeria can cross the placenta, so an infection during pregnancy can cause miscarriage or stillbirth.

Raw poultry is a major source of which bacterium, one of the most common causes of gastroenteritis worldwide?

Campylobacter lives in chickens' guts without making the birds ill, which is why so much raw poultry carries it.

Which paralysing nerve disorder is most commonly triggered by a bacterial infection caught from undercooked chicken?

Guillain-Barré syndrome can follow because antibodies made against the bacterium's surface sugars also latch onto matching sugars on nerve cells.

The 1992-93 E. coli outbreak that killed four children was traced to undercooked beef patties from which chain?

Jack in the Box's outbreak pushed US regulators to declare E. coli O157:H7 an adulterant in raw ground beef, so contaminated meat could be pulled from sale.

Why can cattle carry E. coli O157:H7 without falling ill themselves?

They lack the toxin's receptor, so healthy-looking cattle act as a reservoir, and beef or fresh produce touched by their manure can carry the strain.

Which fish does FDA advice for pregnant women list as a 'choice to avoid' for high mercury?

Swordfish, like other large predatory fish, carries high levels of methylmercury, which can cause intellectual disability in young children.

Honey should not be fed to children under what age because it can contain botulism spores?

12 months is the advised cut-off, because swallowed spores can germinate in a younger child's immature gut and release toxin, which older children's gut defences prevent.

Foodborne botulism has most often resulted from home-canned foods with what characteristic?

Low acid content lets surviving spores grow, and since the spores outlast boiling, commercial canning uses much higher temperatures to kill them.

The word 'botulism' comes from the Latin word for what?

Sausage is the root because the illness was first traced to tainted sausages, and 'sausage poisoning' was an old German name for it.

'Fried rice syndrome' is the nickname for poisoning by which spore-forming bacterium?

Bacillus cereus contaminates starchy foods such as rice and pasta, and leaving them unrefrigerated after cooking lets it build up its vomiting toxin, cereulide.

Which cooking method do food scientists warn can leave red kidney beans' natural toxin intact?

Slow cooking often stays below about 80 °C (176 °F), too cool to destroy the beans' lectin, while a proper boil breaks it down.

Aflatoxins, which contaminate crops such as maize, are produced by which type of organism?

Moulds such as Aspergillus produce them, and in children, exposure to aflatoxins has been linked to stunted growth.

Aflatoxin was discovered after a mysterious 1960 outbreak in England among which animals?

Turkeys, about 100,000 of them, died in England after eating contaminated feed, and tracing what had killed them uncovered aflatoxin.

What happens to the toxin behind ciguatera poisoning when the reef fish is cooked?

It stays just as dangerous, and a toxic fish tastes and smells normal, so the only real protection is avoiding high-risk reef fish such as barracuda.

Trichinosis, often caught from undercooked pork or wild game, is caused by what kind of organism?

A roundworm's larvae hide in muscle, and some species in bears and other wild carnivores survive freezing for years, so only thorough cooking makes the meat safe.

HACCP was developed in the early 1960s by Pillsbury, the US Army and which agency?

NASA needed food that wouldn't make astronauts ill, but testing finished batches used up almost all of it, so the team switched to controlling each production step instead.

Besides meat and seafood, which US drink must be produced under a mandatory HACCP plan?

Juice makers must cut the most resistant harmful microbe at least 100,000-fold, a rule brought in after outbreaks from contaminated juice, including one that killed a child.

The Codex Alimentarius, the international food code founded in 1963, is published by the WHO and which other organisation?

The FAO publishes it with the WHO, and because WTO trade rules reference its standards, countries wanting stricter food rules may have to justify them scientifically.

In Bangladesh, which spice has been adulterated with lead chromate?

Turmeric was polished with the yellow pigment because buyers wanted vividly yellow curries, which exposed the Bangladeshi children who ate it to lead.

Which 1906 novel about Chicago's meatpacking plants prompted the Pure Food and Drug Act?

The Jungle was meant to expose workers' misery, but Sinclair said he 'aimed at the public's heart, and by accident I hit it in the stomach'.

Which US president signed the Pure Food and Drug Act into law in June 1906?

Theodore Roosevelt signed it the same day as the Meat Inspection Act, capping a long campaign by government chemist Harvey Wiley, the law's chief champion.

Which sitcom popularised 'double-dipping', dunking an already bitten chip back into the shared dip?

Seinfeld had George Costanza confronted at a wake for doing it, and Clemson food scientists later found bitten chips really do carry mouth bacteria into dip, salsa picking up the most at first.

Meat, poultry and processed egg products in the US are inspected by an arm of which department?

Agriculture's inspectors examine livestock before slaughter to keep diseased animals out, then check carcasses afterwards for disease that was not visible beforehand.

How does US food-safety guidance say to wash fresh fruit and vegetables at home?

Under plain running water is enough, and US guidance says to rinse even melons whose rind you won't eat and to scrub firm produce with a clean brush.

Harvey Wiley's 'Poison Squad' volunteers ate meals laced with what, to test the effects on health?

Food preservatives such as borax and formaldehyde went into their meals, and the headlines helped build public support for the 1906 Pure Food and Drug Act.

High-temperature short-time (HTST) milk pasteurisation heats milk to about 72 °C for how long?

15 seconds at about 72 °C is calibrated to kill Coxiella burnetii, the most heat-resistant disease germ found in raw milk.

What mainly lets unopened long-life milk sold in cartons keep for months without refrigeration?

Brief sterilising heat, far above boiling for a few seconds, kills even bacterial spores, and sterile cartons then keep new germs out.

Which French confectioner pioneered preserving food by sealing it in glass bottles and heating them?

Nicolas Appert never truly understood why his method worked, since bacteriology didn't yet exist, and in 1810 Peter Durand patented the idea for tin cans.

After a 1915 typhoid outbreak, how did New York stop 'Typhoid Mary' Mallon from spreading the disease for good?

Isolating her on an island, North Brother Island, lasted until her death in 1938, after she broke her 1910 release pledge by taking kitchen work as 'Mary Brown'.

How long does US food-safety guidance say to scrub your hands with soap?

20 seconds is the minimum, and US guidance says to wash before, during and after preparing food and after handling raw meat or poultry.

Which doctor showed in 1847 that handwashing slashed deaths on a Vienna maternity ward?

Ignaz Semmelweis cut deaths sharply by having doctors wash with chlorinated lime after autopsies, yet colleagues rejected his idea until germ theory explained it.

Global Handwashing Day began in 2008, which the UN had declared an International Year of what?

Sanitation got its own UN year to push a neglected cause, since progress in getting people basic sanitation had lagged badly.

Which instruction opens the WHO's Five Keys to Safer Food?

Keep clean comes first, starting with washing your hands before handling food and often while preparing it.

Which allergen in a sandwich caused the death that led to the UK's 'Natasha's Law'?

Sesame was baked into the baguette's dough but missing from its label, so the law now makes food packed where it is sold carry a label listing everything in it.

Which power over most foods did the 2011 Food Safety Modernization Act give the FDA for the first time?

Ordering recalls was new, since before 2011 the FDA could only request them for most foods, and the law also shifted its focus from reacting to outbreaks to preventing them.

Which food is the only one US federal law requires to carry an expiration date?

Infant formula must carry a 'use by' date backed by tests showing it still holds the nutrients on its label, because formula stored too long can lose nutritional value.

Which independent government body polices hygiene in England, Wales and Northern Ireland?

The Food Standards Agency was created in 2000 in the wake of deadly food-poisoning outbreaks, and it is governed by an independent board rather than by ministers.

On UK food labels, what does a 'best before' date mainly tell you?

When quality may start to drop: food is usually still safe after its best before date, unlike a use-by date, which marks when food is no longer safe to eat.

In China's 2008 milk scandal, which chemical was added to watered-down milk to fake a higher protein reading?

Melamine let watered-down milk pass nutrition tests, but it caused kidney stones, and almost 300,000 babies fell ill.

Even without eggs, which ingredient makes raw cookie dough risky to eat, US food-safety officials warn?

The flour is a raw food made from grain grown outdoors, so it can carry germs such as E. coli until baking or heat treatment kills them.

A CDC study found US outbreaks from unpasteurised dairy had a far higher rate of what than pasteurised dairy outbreaks?

Hospitalizations ran far higher, which the study's CDC authors called consistent with more bacterial causes and a larger share of sick children.

Which chocolate egg is barred from US sale by a 1938 law against non-food objects sealed inside sweets?

Kinder Surprise hides a toy capsule inside the chocolate, and the FDA says a child could choke on an object they do not know is there.

Salmonella bacteria are named not after a fish but after an American who worked in which profession?

Veterinarian Daniel Elmer Salmon led the US research group that found the bacterium, though it was his colleague Theobald Smith who actually discovered it.

Pasteurisation was devised in the 1860s, many years before its use on milk, to stop which drink from souring?

Wine came first: Louis Pasteur showed that briefly warming it to about 50–60 °C killed the microbes that turned it sour, and beer and milk followed later.

What do US fire officials advise doing when a frying pan of oil catches fire on the stove?

Cover it with a lid, and the flames die without air. Adding water is the one thing never to do: it makes burning oil flare up violently.

Mixing household bleach with which other common cleaning product releases toxic chloramine gases?

Ammonia and bleach react to form chloramines, toxic gases often mistaken for chlorine; the same reaction happens when bleach meets urine.

Why are the adhesive bandages worn by cooks in professional kitchens usually bright blue?

They show up in food if one falls off mid-shift. Versions made for food factories also carry a metal strip that detection machines can pick up.

Traditional Scottish haggis has been barred from the US since 1971 because it contains which sheep organ?

Lungs are banned from all US food because fluids from the stomach can enter them during slaughter; they make up 10–15% of a traditional haggis.

The FDA's 'defect action level' for chocolate is an average of 60 or more fragments of what per 100 grams?

Insects cannot be kept out of harvested crops entirely, so the FDA sets levels of unavoidable defects it regards as no hazard to health; chocolate has one for rodent hairs too.

Folk wisdom holds that oysters are safe to eat only in months whose names contain which letter?

R is missing from May, June, July and August, the warm months when oysters in the Northern Hemisphere are much more likely to spoil.

The FDA advises that fish served raw, as in sushi, should first be frozen to kill what?

Parasites that some fish species carry are killed by freezing, which is why the FDA's rule of thumb for raw fish is to eat only fish that has been frozen before.

Casu martzu, a Sardinian sheep's-milk cheese banned from sale in Italy, is deliberately infested with what?

Live maggots of the cheese fly are introduced on purpose, and their digestion breaks down the pecorino's fats into a soft, strongly fermented paste.

Which part of the rhubarb plant is poisonous, although its stalks are baked into pies and crumbles?

The leaves hold high levels of oxalic acid, which damages the kidneys, and frost can drive the poison down into the stalks too.

What first aid does the NHS advise for a minor burn or scald from a hot pan?

Cool it under the tap for 20 minutes, the NHS says; once the burn has cooled, kitchen cling film laid over it makes a clean dressing, but butter and oils are out.

In 2013, DNA tests found that beef burgers and lasagne sold across Europe held undeclared meat from which animal?

Horse meat turned up in products labelled as beef, with some Findus ready meals containing up to 100% of it; the fraud first came to light in Irish and British supermarkets.

Where in the fridge does UK food-safety guidance say to keep raw meat and fish, away from ready-to-eat food?

The bottom shelf is the safe spot because nothing sits beneath it, so raw meat cannot leak onto food that will be eaten without cooking.

Under FDA advice, what must happen to frozen meat once it has been thawed in a sink of cold water?

Cooked immediately is the FDA's rule for anything thawed in cold water, and the same goes for the other fast method, the microwave.

According to UK food-safety guidance, what does freezing do to most of the bacteria in food?

Stops them growing, but does not kill most of them: UK guidance calls the freezer a 'pause button' and says to cook and eat defrosted food within 24 hours.

Why does food-safety guidance say to stir food partway through microwaving it?

To even out cold pockets: microwaves heat food unevenly, and bacteria can survive in any patch that never gets steaming hot.

What has research found about water temperature when washing hands with soap, the CDC reports?

It makes no difference to how many germs come off; warmer water may simply irritate skin more and costs more energy, so cold does the job just as well.

Why does UK food-safety guidance say never to trust the 'sniff test' on food past its use-by date?

Harmful bacteria have no smell, taste or look, so food can seem normal and still make you ill; the bugs that make food smell off are a different set.

Which bacterium, carried in the nose of about one in four people, makes a food toxin that cooking cannot destroy?

Staphylococcus aureus rarely harms the people who carry it, but unwashed hands can pass it to food, where it multiplies and makes a toxin that survives cooking.

Which bacteria, at home in warm coastal waters, are a well-known hazard of eating raw oysters?

Vibrio thrive when coastal waters are at their warmest, and they can also infect an open wound that meets seawater.

Which vaccine-preventable virus, spread through contaminated food and drink, causes a disease of the liver?

Hepatitis A can leave people ill for weeks or even months, but most recover completely with no lasting liver damage.

Toxoplasmosis, a danger in pregnancy, is caught from undercooked meat or from the droppings of which pet?

Cats shed the organism in their droppings, which is why pregnant women are advised not to clean the litter box, or to wear gloves if they must.

The gut bacterium E. coli takes its full name from which German-Austrian paediatrician, who first described it?

Theodor Escherich found it while studying the gut bacteria of babies and gave it a simple Latin name meaning common colon bacterium; it was renamed in his honour later.

Scombroid poisoning, which mimics an allergic reaction after eating badly stored tuna, is caused by which compound?

Histamine forms when bacteria get to work on fish left too warm, and no amount of cooking, smoking or canning destroys it afterwards.

Potatoes that turn green after exposure to light build up higher levels of which bitter natural poison?

Solanine is the potato's own defence against pests, made alongside the harmless green chlorophyll when light hits the tuber; damage and poor storage raise its level too.

Which tropical root crop, used to make tapioca, can release poisonous cyanide if it is not prepared properly?

Cassava feeds more than half a billion people, yet eaten raw it releases hydrogen cyanide from compounds in its roots and peels.

Which mushroom, easily mistaken for edible species, is responsible for most fatal mushroom poisonings worldwide?

Death cap poisoning may even have changed history: the mushroom is suspected in the deaths of the Roman emperor Claudius and Holy Roman Emperor Charles VI.

Which national fruit of Jamaica is poisonous if eaten before it ripens and splits open on the tree?

Ackee is paired with saltfish in Jamaica's national dish, yet its unripe flesh can hold 10 to 100 times more of the poison hypoglycin.

Ergotism, the medieval 'St Anthony's fire', came from eating bread made with fungus-infected grain of which cereal?

Rye was the main carrier of the ergot fungus, whose alkaloids bring on convulsions and narrow the blood vessels so severely that limbs can turn gangrenous.

Which Japanese city gave its name to a disease caused by eating seafood tainted with a factory's mercury waste?

Minamata Bay took in methylmercury from a chemical factory's wastewater from 1932 to 1968, and the poison built up in the fish that local families ate.

In 1858, sweets sold at a market in Bradford, England, killed around 20 people after being accidentally made with what?

Arsenic was supplied by mistake for the powdered gypsum the sweet maker used to stretch costly sugar; the deaths led to the Adulteration of Food or Drink Act 1860.

Spain's 1981 'toxic oil syndrome', which killed over 300 people, was blamed on which oil meant only for industry?

Rapeseed oil imported for industry had been dosed with aniline to keep it out of food, but it was eaten anyway, and more than 20,000 people fell ill.

British eggs stamped with which animal come from hens that must be vaccinated against Salmonella?

Lion marks go on eggs from farms signed up to a code of practice that also sets rules for hen welfare, feed, traceability and freshness.

The European Food Safety Authority has its headquarters in which food-famous city of Italy's Emilia-Romagna region?

Parma, home of Parma ham and Parmesan, hosts the EU body that gives independent scientific advice on risks in the food chain.

ServSafe, the food-handler certificate held by millions of US kitchen staff, is run by which trade body?

National Restaurant Association courses have awarded more than 5 million ServSafe manager certifications, and the scheme also extends to alcohol service and allergens.

New York's 1850s 'swill milk' scandal involved milk from sickly cows fed on the waste mash of which businesses?

Distilleries had cheap leftover mash, so dairies stabled cows beside them; the thin milk was whitened with plaster of Paris, and one estimate blamed it for 8,000 babies' deaths in a year.

The 'embalmed beef' scandal concerned foul, adulterated meat supplied to US Army soldiers during which war?

Spanish–American War troops in 1898 fell ill with dysentery and food poisoning from the meat, and it was General Nelson Miles who gave it its grim nickname.

Followers of the guru Rajneesh poisoned restaurant food in 1984 in which US state, America's largest bioterror attack?

Oregon's town of The Dalles saw 751 people fall ill after cult members spread Salmonella in ten restaurants, hoping to keep voters at home in a county election.

A badly washed tanker that had carried raw eggs caused a 1994 Salmonella outbreak in which Schwan's product?

Ice cream pre-mix was delivered in the tanker after its cargo of unpasteurised eggs, and Schwan's halted production once Minnesota health officials spotted the link.

What does the FDA say must happen to a plate that held raw burgers before it carries the cooked ones?

A hot, soapy wash is the minimum, the FDA says, because raw meat deposits bacteria on the plate that would go straight onto the cooked food.

Salt preserves food by drawing water out of microbial cells through which process?

Osmosis pulls the water out of any living cell that sits in a very salty environment, so microbes dry out and either die or go dormant.

Which crunchy vegetable is one of the 14 allergens that UK food businesses must declare by law?

Celery sits on the UK's list of 14 alongside mustard, lupin and molluscs; none of those four is among the major allergens that US labels must declare.

What does the FDA say to do with a marinade used on raw meat before serving it as a sauce?

Boil it first, because the liquid has been soaking up whatever bacteria were on the raw meat, and only boiling makes it fit to pour over cooked food.

What does the FDA say about putting still-hot leftovers straight into the refrigerator?

It is perfectly fine and does the fridge no harm, the FDA says; dividing the food into shallow containers simply helps it chill faster.

A CDC study of US outbreaks from 1998 to 2008 tied more illnesses to which food group than to any other?

Leafy vegetables were tied to 22% of illnesses, more than any kind of meat, although poultry was linked to the largest share of deaths.

Which chemical, classed as a probable carcinogen, forms when starchy foods such as potatoes are cooked above 120 °C?

Acrylamide was only found in food in 2002, in the browned parts of fried and baked starches, and whether the amounts people eat cause cancer is still debated.

An international food-label symbol of a plant inside a circle shows that the food has had which treatment?

Irradiation is flagged by the Radura, a logo usually printed in green that was devised at a pilot food irradiation plant in Wageningen in the Netherlands.

Which tree's roots flavoured traditional American root beer until the FDA banned its oil from food in 1960?

Sassafras oil is rich in safrole, which caused liver cancer in animal studies, so commercial root beers had to find other flavourings.