Updated 07 October 2015

Food safety - from Natural Standard

Food safety refers to the conditions and practices that preserve the quality of food to prevent contamination and foodborne illnesses (those transmitted by food or beverages).



Most foodborne diseases are infectious and are caused by bacteria, viruses, and parasites. Other foodborne diseases are poisonings caused by toxins, which are harmful compounds contaminating food.

Such toxins may be naturally occurring as in poisonous mushrooms or may be environmental pollutants such as mercury in fish.

Foodborne illness occurs when an infectious or toxic agent enters the body through the gastrointestinal tract. Symptoms of foodborne illness often include nausea, vomiting, abdominal cramps, and diarrhoea.

According to the U.S. Centres for Disease Control and Prevention (CDC), about 76 million cases of foodborne disease occur each year in the United States. More than half are caused by viruses (e.g., noroviruses).

Illnesses caused by bacteria (such as Salmonella and Campylobacter) are also common. Most cases are mild and cause symptoms for only one or two days.

However, some cases are more serious: The CDC estimates that there are about 325,000 hospitalizations and 5,000 deaths related to foodborne diseases annually in the United States.

The most severe cases of foodborne disease tend to occur in people who are very old or very young, in people who are immuno-compromised, or in healthy people who are exposed to a very large amount of a toxic or infectious microorganism.

Foodborne diseases caused by parasites such as Entamoeba hystolytica, Giardia lamblia, and Toxoplasma gondii are much more common in developing countries than in the United States and other developed nations. In some developing regions, parasitic infections are a major cause of childhood diarrhea and stunting of growth.

Many foodborne diseases are specific to certain locations throughout the world. Long-term residents may develop immunity to local infectious organisms, while tourists or newcomers may develop "traveler's diarrhea." E. coli bacteria are a frequent cause of traveler's diarrhoea.

A foodborne disease outbreak occurs when a group of people eats contaminated food, after which two or more of these people are diagnosed with the same illness. Most outbreaks are local in nature and may occur, for example, after a potluck supper or a catered reception.

However, widespread outbreaks are becoming more common. Recent outbreaks in multiple U.S. states have involved Salmonella in peanut butter, Salmonella in raw jalapeno and serrano peppers, and E. coli from bagged spinach .

One factor contributing to these widespread outbreaks is the growing complexity of the food supply. In the outbreak involving peanut butter, for example, a small Georgia plant sold contaminated peanuts or peanut paste to hundreds of manufacturers; these manufacturers then used the peanuts and paste to make thousands of consumer products.

The growing complexity of the food supply has made government oversight more difficult. In March 2009, President Barack Obama announced that a Food Safety Working Group would be created to advise him on how to improve the inspection and regulation of food in the United States.

Steps that consumers can take to reduce the risk of foodborne illnesses include the frequent washing of hands and kitchen surfaces; keeping raw meat, poultry, seafood, and eggs away from ready-to-eat foods; cooking food to proper temperatures; and refrigerating foods promptly.


Diagnosing foodborne illness:

The symptoms of foodborne diseases vary depending on the type of microorganism that is causing the infection and the amount of contaminants eaten. Symptoms generally affect the gastrointestinal tract, causing nausea, vomiting, abdominal cramping, diarrhoea, and sometimes blood in the stool.

Other common symptoms include headache, fever, and exhaustion. In some cases, particularly in older adults, young children, and in people with compromised immunity, symptoms may be severe.

Some parasitic infections may cause malnutrition and significant weight loss.

The U.S. Centres for Disease Control and Prevention (CDC) recommends consulting a healthcare provider if a diarrhoeal illness is accompanied by a high fever, bloody stools, prolonged vomiting that makes it difficult to retain fluids, signs of dehydration, or if diarrhoeal illness lasts more than three days.

People experiencing neurological symptoms, such as blurred vision and slurred speech, should seek immediate medical attention. These problems may be signs of botulism, a rare but deadly form of food poisoning.

Foodborne infections may be diagnosed by specific laboratory tests that identify the organism responsible for the infection. Bacteria such as Campylobacter, Salmonella, and E. coli O157 are found by culturing stool samples in the laboratory and identifying the bacteria that grow on the culture medium.

Parasites may be identified by examining stool samples under a microscope. Viruses are more difficult to identify: They are too small to see under an ordinary microscope and are difficult to culture.

Viruses may be identified by testing stool samples for genetic markers that indicate a specific virus is present; such tests may be expensive, however, and are not widely available.

Many cases of foodborne illness go undiagnosed. For example, the CDC estimates that 38 cases of salmonellosis (the illness caused by Salmonella) occur for every case that is diagnosed and reported to public health authorities.

Many people with foodborne illness do not seek medical attention, especially if the illness lasts for only one or two days. In addition, most doctors do not routinely test for noroviruses or other viral causes of foodborne infections.

Treating foodborne illness:

Different foodborne diseases may require different remedies; treatment examples include antibiotics used to treat bacterial infections and antiparasitic drugs for parasitic infections. For noroviruses, staying hydrated and getting plenty of rest is often the recommended treatment.

Antidiarrheal drugs may relieve symptoms of foodborne illness, but should be avoided if the person has bloody stools or a fever because such medications may worsen the illness.

Foodborne illnesses that primarily cause diarrhea or vomiting may lead to dehydration if affected people lose more body fluids and salts (electrolytes) than they take in. If diarrhea is severe, an oral rehydration solution should be drunk to replace the lost fluids and prevent dehydration.

Sports drinks such as Gatorade© should not be used to treat diarrhoeal illness, because they do not replace fluids in the correct proportions.

Tracking foodborne illness:

Public health officials investigate outbreaks of foodborne illness in order to control them and to learn how to prevent similar outbreaks in the future. In most states in the United States, diagnosed cases of salmonellosis, E. coli O157:H7, and other serious infections are routinely reported to the local public health department; the reports are then forwarded to the state health department, which sends them to the CDC.

However, most foodborne infections go undiagnosed and unreported because the ill person does not see a doctor, the doctor is unable to make a specific diagnosis, or the physician fails to report the diagnosis to public health officials.

To obtain more information about infections that might be diagnosed but not reported, the CDC uses a special surveillance system called FoodNet. Government epidemiologists routinely survey 650 clinical laboratories that serve about 46 million people in 10 states.

These scientists collect data on laboratory-confirmed infections that have been transmitted from bacteria- and parasite-contaminated food. Such active surveillance tends to be more accurate than disease-tracking methods that rely on voluntary reporting by doctors and hospitals.

In addition to tracking reported cases of individual infections, states also collect information about foodborne outbreaks and report a summary of that information to the CDC. About 500 foodborne outbreaks with confirmed causes are reported each year.

The hardest outbreaks to detect are those that are spread over a large geographic area, with only a few cases in each state. These outbreaks may be detected by combining surveillance reports at the regional and national levels and looking for increases in infections of a specific type.

Newer "DNA fingerprinting" technologies are making outbreaks easier to detect by allowing researchers around the United States to compare strains of E. coli O157:H7 with a growing number of other microorganisms.

As global trade has increased, so has the potential for the spread of foodborne disease via imported foods. In 2004, the World Health Organization (WHO), along with the United Nations' Food and Agriculture Organisation (FAO), established the International Food Safety Authorities Network (INFOSAN) to improve the exchange of information among more than 175 participating countries.

Regulating the food supply:

In the United States, the primary agencies that inspect and regulate food are the U.S. Department of Agriculture (USDA), which oversees meat, poultry, and processed egg products; and the Food and Drug Administration (FDA), which has regulatory responsibility for all other foods, in addition to animal feed.

A 2008 report by the U.S. Government Accountability Office (GAO) concluded that the FDA lacks the inspectors, staffers, and scientists to safeguard the food supply, particularly fresh produce items. Problems were detected at 42% of 2,002 produce plants inspected by the FDA between 2000 and 2007, yet the agency typically relied on the plant owners to voluntarily correct the problems.

In addition, only one per cent of produce imported into the United States is inspected by the FDA, even though 60% of all fresh fruits and vegetables sold in the United States is imported each year.

In April 2008, the FDA barred certain cattle materials from all animal feed to help protect animals and people from bovine spongiform encephalopathy (BSE), also known as "mad cow" disease; earlier regulations offered other safeguards.

Prohibited materials include tissues that have the highest risk for carrying the agent thought to cause BSE, such as the brains and spinal cords of cattle that are 30 months of age and older.

Restaurants are inspected by local health departments to make sure that they are clean and have adequate kitchen facilities. Inspectors seek to identify risk factors for foodborne illness, such as improper hand washing by restaurant staff, inadequate cooking temperatures, and poor sanitizing of food contact surfaces.

Violations may cause the restaurant to be fined or even shut down until the problems are corrected. In many jurisdictions, the latest inspection score is posted in the restaurant. Consumers should avoid restaurants that look dirty or seem poorly maintained. Hot meals should be served hot and thoroughly cooked, and fresh foods should look and smell fresh.

Food safety regulations vary from country to country. In 2007, the WHO implemented a set of rules called the International Health Regulations (IHR); these regulations help public health officials in each country to determine what kind of disease outbreaks (including foodborne outbreaks) need to be reported to the WHO. International outbreaks need to be reported, as well as national outbreaks that are serious or unusual.


Causes of contamination:

Microbes in animals raised for food: There are many opportunities for food to become contaminated during production and preparation. Various bacteria and other disease-causing microbes (microscopic organisms) are often present in the intestines of healthy animals that are raised for food.

Meat and poultry carcasses may become contaminated during slaughter by contact with small amounts of intestinal contents. Similarly, fresh fruits and vegetables may be contaminated if they are washed or irrigated with water that is polluted with animal manure or human sewage.

Irrigation water may be contaminated by fertilizer runoff, sewage spills, and illegal discharge of waste, among other factors.

Unwashed hands and cross contamination: Foodborne microbes may be spread by infected humans who handle food or by cross-contamination from other raw agricultural products. For example, Shigella bacteria, hepatitis A virus, and noroviruses may be introduced to food by infected restaurant workers who did not wash their hands after using the bathroom.

In the kitchen, microbes may be transferred from a contaminated food to another food by using the same knife, cutting board or other utensil to prepare both foods, without washing the preparation surface or utensil in between.

Inadequate refrigeration and inadequate cooking: Temperature may affect whether a contaminated food actually causes illness. Bacterial microbes may multiply rapidly at room temperature, meaning that a lightly-contaminated food left out overnight may be highly infectious by the next day. Refrigeration or freezing prevents virtually all bacteria from growing, but generally preserves them in a state of suspended animation.

Cooking food sufficiently kills microbes, including parasites, viruses, and bacteria. For instance, most meat products, including ground beef, should be heated to an internal temperature of at least 160 degrees Fahrenheit. Fish should be heated to 145 degrees, or until the flesh is opaque and separates easily with a fork. One exception is Clostridium bacteria, which produce a heat-resistant form called a spore. Clostridium spores are killed only at temperatures above boiling (212 degrees Fahrenheit). For this reason, canned foods must be cooked to a high temperature under pressure as part of the canning process. Clostridium botulinum, which causes botulism, is most often associated with improperly home-canned foods such as peppers, beans, spinach, and asparagus; Clostridium perfringens food poisoning is frequently linked to cold, cooked, or reheated meats and meat products.

Before the advent of refrigeration and modern food-preservation methods, people used high concentrations of salt or sugar, along with a high acid content, to keep foods from spoiling. These traditional methods, still used to make jams, jellies, salted meats and pickled vegetables, may kill bacteria or keep them from growing.

Naturally-occurring toxins: Some species of Amanita mushrooms produce powerful toxins; these mushrooms may be deadly if gathered and consumed by inexperienced wild mushroom collectors. Some types of fish also contain natural toxins (see "Foods of most concern," below).

Environmental pollutants: Mercury from industrial pollution may contaminate fish and other seafood, and pesticide residues may contaminate fruits and vegetables.

Foods of most concern :

Raw animal products: Some foods increase the risk of foodborne illness; these foods include raw or undercooked meat or seafood (including steak tartare, rare ground beef, sushi, and raw oysters), raw or undercooked eggs (including poached eggs), and unpasteurized milk. Older adults, young children, pregnant or nursing women, and others at high risk for foodborne disease should avoid these foods.

Foods such as bulk raw milk, pooled raw eggs, or ground beef are particularly hazardous, because they may contain material from many individual animals. For example, a single hamburger many contain pieces of meat from hundreds of animals. A disease-causing microbe present in any one of the animals may contaminate the whole batch of food.

Seafood: Because filter-feeding shellfish (such as clams, oysters, and mussels) may collect microbes from the sea over many months, they are particularly likely to be contaminated if there are any disease-causing organisms in the seawater.

Fish and other seafood may also be contaminated by environmental pollutants, such as mercury and polychlorinated biphenyls (PCBs). PCBs are toxic compounds once widely used for industrial applications. Although the manufacture of these chemicals was banned in the United States in the 1970s, PCBs may still be found in the environment; they break down slowly and persist for many years. PCBs also accumulate in the fatty tissue of fish and people.

According to the nonprofit Environmental Defense Fund, the types of seafood that tend to have the highest levels of mercury or PCBs are alewife, wild striped bass, bluefish, white croaker, American and European eel, king mackerel, marlin, shad, shark, imported wild sturgeon, swordfish, bluefin tuna, and weakfish. The types of seafood that tend to have the lowest mercury or PCB levels are Dungeness crab, monkfish, Florida pompano, wild Alaskan salmon, black sea bass, skate, albacore tuna (from the United States and Canada), and canned light tuna.

Some types of fish contain natural toxins. Certain puffer fish, called fugu fish in Japan, may produce tetrodotoxin; this toxin is harmless to the fish, but may cause death within 30 minutes of consumption in people eating fugu. Nonetheless, fugu is considered a delicacy in Japan, and only specially-licensed chefs are allowed to prepare it. Snappers and other marine finfish that live near coral reefs may feed on algae that produce ciguatera toxin, and eating these fish may cause ciguatera poisoning.

Produce: Washing fruits and vegetables may decrease but not eliminate bacterial contamination. In recent years, several foodborne outbreaks have been traced to fresh produce that was processed under less-than-sanitary conditions. The quality of the water used for washing and chilling produce after it is harvested is critical: Using unclean water may contaminate many boxes of produce at once. Fresh manure that is used to fertilize vegetables may also contaminate them. Fertilizer made from properly-composted manure or heat-treated manure, however, is unlikely to pose contamination problems.

Fruits and vegetables may also be contaminated by pesticide residues. According to the nonprofit Environmental Working Group (EWG), the "dirty dozen" fruits and vegetables that tend to have the highest levels of pesticide residues are peaches, apples, bell peppers, celery, nectarines, strawberries, cherries, kale, lettuce, imported grapes , carrots, and pears. EWG recommends that shoppers buy organic versions of these items, several of which are fruits with thin, edible skins. The "clean 15" fruits and vegetables lowest in pesticide residues are onions, avocado, sweet corn, pineapple, mango, asparagus, sweet peas, kiwi, cabbage, eggplant, papaya, watermelon, broccoli, tomatoes, and sweet potatoes. Many of these "cleaner" items have thick skins or husks that help to protect the products' interiors from pesticide residues.

Alfalfa sprouts and other raw sprouts may contain bacteria that cause foodborne illness, because the conditions under which these products sprout are also ideal for growing microbes. A few bacteria present on the seeds may grow to high numbers of microbes on the sprouts.

Unpasteurized fruit juice may be contaminated if there are disease-causing microbes in or on the fruit used to make the juice.


Foodborne illnesses :

Incubation period: After disease-causing microbes are swallowed, there is a delay called the incubation period before the symptoms of illness begin. This delay may last from hours to days, depending on the organism and on how many of the microbes were swallowed. Parasitic infections tend to have longer incubation periods. Healthy adults who ingest only trace amounts may develop few or no symptoms. During the incubation period, the microbes pass through the stomach into the intestine, attach to the cells lining the intestinal walls, and begin to multiply. Some types of microbes stay in the intestine, while some produce a toxin that is absorbed into the bloodstream, and some may directly invade deeper body tissues.

Common foodborne illnesses: The most common foodborne diseases are those caused by the bacteria Campylobacter, Salmonella, E. coli O157:H7 and by a group of viruses called noroviruses (also known as Norwalk-like viruses).

Campylobacter is a bacterial microbe that lives in the intestines of healthy birds; most raw poultry meat has this bacterium in it. Eating undercooked chicken or other food contaminated with juices dripping from raw chicken is the most frequent cause of infection. Symptoms include fever, diarrhea, and abdominal cramps.

Salmonella is a bacterium that is widespread in the intestines of birds, mammals, and reptiles. It may spread to humans via various foods of animal origin, such as raw meat, poultry, seafood, and raw eggs. The illness caused by Salmonella (salmonellosis), typically causes fever, diarrhea, and abdominal cramps. In people with poor underlying health or weakened immune systems, it may invade the bloodstream and cause life-threatening infections.

In rare cases, Campylobacter, Salmonella, and some other bacteria have been linked to the development of arthritis. More research is needed to better understand this association.

E. coli O157:H7: E. coli is a bacterial microbe found in cattle and similar animals. Infected animals may become ill, but even animals that appear healthy may be carriers of the microbe. Human illness is typically caused by consuming food or water that has been contaminated by microscopic amounts of cow feces. Common sources include undercooked ground beef, unpasteurized milk, and unwashed produce. Symptoms often include severe, bloody diarrhea and painful abdominal cramps; fever infrequently occurs. In 3-5% of cases, a severe complication called hemolytic uremic syndrome (HUS) may occur several weeks after the initial symptoms. Temporary anemia, profuse bleeding, and kidney failure are among the symptoms of HUS.

Noroviruses, also known as Norwalk-like viruses, are a very common cause of foodborne illness; they are rarely identified, however, because diagnostic laboratory tests are not widely available. Noroviruses are thought to spread from one infected person to another. If noroviruses are present on the hands of kitchen workers, the workers may then contaminate salads or sandwiches that are being prepared. Norovirus symptoms generally end within two days; in this illness, vomiting occurs more frequently than diarrhea.

Some common diseases are occasionally foodborne, even though they are usually transmitted by other routes: Examples include infections caused by Shigella, hepatitis A, and the parasites Giardia lamblia and Cryptosporidia.

Some foodborne diseases are caused by toxins produced by microbes in food. For instance, the bacterium Staphylococcus aureus may produce a toxin in foods that causes intense vomiting. Botulism, a rare but deadly disease, occurs when the bacterium Clostridium botulinum grows and produces a powerful toxin in foods.

Trends: In 1996, the U.S. Centers for Disease Control and Prevention (CDC) began collecting detailed data from five states on people with infections caused by various bacteria and parasites found in food. The CDC now collects such data from 10 states that have a total population of about 46 million people (15% of the U.S. population). Data from these states appear to be generally representative of the entire United States, although the Hispanic population may be underrepresented.

Between 1996 and 2008, the incidence of Campylobacter, Listeria, Shigella, E. coli O157, and Yersinia decreased, although this decreasing trend has stalled: Since 2004, there has been no statistically significant change in the incidence of salmonellosis and Cryptosporidia. There has also been a marked increase in the incidence of Vibrio, which is a relatively rare disease linked to the ingestion of raw oysters.

The lack of progress since 2004 may be due to several factors, including the growing complexity of the U.S. food chain, a rise in imported foods that has outpaced resources devoted to inspection, and the changing nature of the contaminating organisms. Bacteria once linked mainly with meat and poultry, such as E. coli O157 and Salmonella, are increasingly showing up in fresh produce. Only one percent of foods imported into the United States are currently inspected, even though about 60% of fresh fruits and vegetables and 75% of seafood that Americans consume is from other countries.

Recent outbreaks: Examples of outbreaks affecting multiple U.S. states include: Salmonella in peanut butter and other peanut products (2008-2009: more than 700 people sickened across 46 states); Salmonella in raw jalapeno and serrano peppers grown in Mexico (2008: one person dead and at least 1,000 people sickened across 41 states and Canada); and E. coli O157 in bagged spinach (2006: three people dead and 198 people sickened across 25 states). Initially, the 2008 outbreak involving peppers was mistakenly thought to be caused by raw tomatoes, because fresh peppers are often eaten together with tomatoes in salsa. It took public health officials more than two months to pinpoint the source of the outbreak, which indicates the difficulty of such a task in today's globally-interconnected economy.

People at greater risk: Pregnant women, the elderly, and those with weakened immune systems are at a higher risk for severe infections such as Listeria and should be particularly careful not to consume undercooked animal products; they should also avoid soft French-style cheeses, pates, uncooked hot dogs, and sliced deli meats, which have been sources of Listeria infections. Individuals at high risk should, in addition, avoid alfalfa sprouts and unpasteurized juices.

Bottle-fed infants are at higher risk for severe infections with Salmonella or other bacteria; these bacteria may grow in bottles of warm formula if the containers are left at room temperature for many hours.

People with liver disease are susceptible to infection through the consumption of raw oysters; these oysters may contain a rare but dangerous microbe called Vibrio vulnificus.

Preventive measures: The CDC suggests that consumers take several precautions to reduce the risk of foodborne diseases: Use a food thermometer to make sure that meat, poultry, and egg dishes are cooked thoroughly; cook ground beef and egg dishes to an internal temperature of 160 degrees (by themselves, eggs should be cooked until the yolk is firm); and cook poultry to 165 degrees.

Avoid the cross-contamination of foods: Use hot soapy water to wash hands, utensils, and cutting boards after they have been in contact with raw meat, poultry, and eggs, and before these items touch other foods; refrigerate leftover foods if they are not going to be eaten within four hours; rinse fresh fruits and vegetables in running water to remove visible dirt and grime; wash hands with soap and water before preparing food; and avoid preparing food for others when suffering from a diarrheal illness.

Consumers may help public health officials detect foodborne disease outbreaks by reporting confirmed or suspected foodborne illnesses to the local public health department.

People who are traveling to developing countries or to areas where there is poor sanitation may reduce the risk of foodborne illness by limiting raw foods. These individuals should avoid salads, uncooked vegetables, and unpasteurized milk and milk products such as cheese; in addition, travelers should only eat food that has been cooked and is still hot, or fruit that they can wash and peel themselves. Other preventive measures include the avoidance of food sold by street vendors and the drinking of beverages that have been bottled or sealed. Travelers should not put ice in their drinks, because the water used to make the ice may have been contaminated.

Other types of contamination :

Naturally occurring toxins: Amanita mushrooms or fugu fish, both of which contain powerful toxins, may be deadly if eaten. However, these foods do not enter the general food supply, and poisonings are rare. Ciguatera poisoning from eating coral-reef fish that feed on toxin-producing algae may cause tingling of the lips and tongue, nausea, vomiting, diarrhea, headaches, heart palpitations, and breathing difficulties. A common treatment for toxic poisonings is activated charcoal, which binds with any unabsorbed toxins.

Environmental pollutants: Fish and shellfish that have been contaminated with mercury may harm the developing nervous systems of unborn babies, infants, and young children; it may affect their coordination and how they think, learn, and problem-solve later in life. Discontinuing consumption of mercury-contaminated fish causes blood levels of mercury to decline over several months, but developmental and neurological damage may be irreversible in some cases.

The U.S. Food and Drug Administration (FDA) and the U.S. Environmental Protection Agency (EPA) advises pregnant women, nursing mothers, and young children to avoid the consumption of fish containing high levels of mercury (shark, swordfish, king mackerel, and tilefish); they are also advised to eat up to 12 ounces per week of fish and shellfish that are lower in mercury (including shrimp, canned light tuna, salmon, pollock, and catfish). Individuals should also check advisories about the safety of fish caught in local lakes, rivers, and coastal areas.

Polychlorinated biphenyls (PCBs), pollutants that may contaminate fish and other seafood, are considered "probable human carcinogens" by the EPA.

Produce manufacturers claim that the amounts of pesticide residues on fruits and vegetables are too low to cause health problems and that scientists do not yet have a clear understanding of the long-term effects of these residues. Children may be more susceptible to developmental and neurological effects from pesticide exposure.


Consumer groups such as Consumers Union and the Center for Science in the Public Interest have long claimed that safeguards on the U.S. food supply are fragmented, understaffed, and under-funded. A 2008 report by the U.S. Government Accountability Office (GAO) found significant problems in oversight by the Food and Drug Administration (FDA). In March 2009, President Barack Obama announced the creation of a Food Safety Working Group; this group will include the Secretaries of both Health and Agriculture, to advise him on which laws and regulations need to be changed, to bolster coordination across federal agencies, and to ensure that laws are enforced.

In August 2008, the FDA announced that it would allow food producers to "zap" raw iceberg lettuce and spinach with enough radiation (a process called irradiation) to kill dangerous germs like salmonella and E. coli. The greens would most likely be irradiated after they are bagged, a process that would prevent the risk of re-contamination.

Although this is the first time that the FDA has allowed any produce to be irradiated at levels needed to prevent food poisoning, irradiated meat has been sold in stores for years. Eggs, poultry, oysters and spices may also be irradiated. Few companies use this technology, however; the U.S. government requires these foods to be labeled as irradiated, which is a regulation that scares away many consumers.

Wider use of food irradiation has the potential to improve U.S. food safety. Food irradiation may kill bacteria and parasites that might otherwise cause foodborne disease.

One area for future research is the rising rate of foodborne disease outbreaks linked to leafy green vegetables. Between 1986 and 1995, U.S. consumption of leafy greens increased 17% from the previous decade, but the proportion of foodborne disease outbreaks due to leafy greens jumped 60%.

Between 1996 and 2005, leafy green consumption increased by 9% and outbreaks due to leafy greens rose 39%. Some outbreaks were widespread, suggesting that contamination occurred on the farm or in the processing plant.

To better understand the extent and impact of foodborne illness, the World Health Organisation (WHO) has launched the Initiative to Estimate the Global Burden of Foodborne Diseases.

The project will assemble existing epidemiological evidence and strengthen the capacity of countries to conduct their own studies on the burden of foodborne disease.

Author Information

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (

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