- Food safety, nutrition, and food security are inextricably linked.
- An estimated 600 million – almost 1 in 10 people in the world – fall ill after eating contaminated food and 420 000 die every year, resulting in the loss of 33 million healthy life years (DALYs).
- US$ 110 billion is lost each year in productivity and medical expenses resulting from unsafe food in low- and middle-income countries.
- Children under 5 years of age carry 40% of the foodborne disease burden, with 125 000 deaths every year.
- Foodborne diseases impede socioeconomic development by straining health care systems and harming national economies, tourism, and trade.
Access to sufficient amounts of safe and nutritious food is key to sustaining life and promoting good health. Unsafe food containing harmful bacteria, viruses, parasites, or chemical substances causes more than 200 diseases, ranging from diarrhea to cancer. It also creates a vicious cycle of disease and malnutrition, particularly affecting infants, young children, the elderly, and the sick. Good collaboration between governments, producers, and consumers is needed to help ensure food safety and stronger food systems.
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Major foodborne illnesses and causes
Foodborne illnesses are usually infectious or toxic in nature and caused by bacteria, viruses, parasites, or chemical substances entering the body through contaminated food. Chemical contamination can lead to acute poisoning or long-term diseases, such as cancer. Many foodborne diseases may lead to long-lasting disability and death. Some examples of food hazards are listed below.
- Salmonella, Campylobacter, and enterohaemorrhagic Escherichia coli are some of the most common foodborne pathogens that affect millions of people annually, sometimes with severe and fatal outcomes. Symptoms can be fever, headache, nausea, vomiting, abdominal pain, and diarrhea. Foods involved in outbreaks of salmonellosis include eggs, poultry, and other products of animal origin. Foodborne cases with Campylobacter are mainly caused by raw milk, raw or undercooked poultry, and drinking water. Enterohaemorrhagic Escherichia coli is associated with unpasteurized milk, undercooked meat, and contaminated fresh fruits and vegetables.
- Listeria infections can lead to miscarriage in pregnant women or the death of newborn babies. Although disease occurrence is relatively low, Listeria’s severe and sometimes fatal health consequences, particularly among infants, children, and the elderly, count them among the most serious foodborne infections. Listeria is found in unpasteurized dairy products and various ready-to-eat foods and can grow at refrigeration temperatures.
- Vibrio cholerae can infect people through contaminated water or food. Symptoms may include abdominal pain, vomiting, and profuse watery diarrhea, which quickly lead to severe dehydration and possibly death. Rice, vegetables, millet gruel, and various types of seafood have been implicated in cholera outbreaks.
Antimicrobials, such as antibiotics, are essential to treat infections caused by bacteria, including foodborne pathogens. However, their overuse and misuse in veterinary and human medicine have been linked to the emergence and spread of resistant bacteria, rendering the treatment of infectious diseases ineffective in animals and humans.
Some viruses can be transmitted by food consumption. Norovirus is a common cause of foodborne infections that are characterized by nausea, explosive vomiting, watery diarrhea, and abdominal pain. Hepatitis A virus can also be transmitted by food and can cause long-lasting liver disease and spreads typically through raw or undercooked seafood or contaminated raw produce. For more information please visit Pritish Kumar Halder ‘s page.
Some parasites, such as fish-borne trematodes, are only transmitted through food. Others, for example, tapeworms like Echinococcus spp, or Taenia spp, may infect people through food or direct contact with animals. Other parasites, such as Ascaris, Cryptosporidium, Entamoeba histolytica, or Giardia, enter the food chain via water or soil and can contaminate fresh produce.
Prions, infectious agents composed of protein, are unique in that they are associated with specific forms of neurodegenerative disease. Bovine spongiform encephalopathy (BSE, or so-called mad cow disease) is a prion disease in cattle, associated with the variant Creutzfeldt-Jakob disease (vCJD) in humans. Consuming meat products containing specified risk material, such as brain tissue, is the most likely route of transmission of the prion agent to humans.
Most health concerns are naturally occurring toxins and environmental pollutants.
Naturally occurring toxins include mycotoxins, marine biotoxins, cyanogenic glycosides, and toxins occurring in poisonous mushrooms. Staple foods like corn or cereals can contain high levels of mycotoxins, such as aflatoxin and ochratoxin, produced by mold on grain. Long-term exposure can affect the immune system and normal development, or cause cancer.
Persistent organic pollutants (POPs) are compounds that accumulate in the environment and the human body. Known examples are dioxins and polychlorinated biphenyls (PCBs), which are unwanted by-products of industrial processes and waste incineration. They are found worldwide in the environment and accumulate in animal food chains. Dioxins are highly toxic and can cause reproductive and developmental problems, damage the immune system, interfere with hormones, and cause cancer.
Heavy metals such as lead, cadmium, and mercury cause neurological and kidney damage. Contamination by heavy metals in food occurs mainly through the pollution of water and soil.
Other chemical hazards in food can include radioactive nucleotides that can be discharged into the environment from industries and civil or military nuclear operations, food allergens, residues of drugs, and other contaminants incorporated in the food during the process.
The burden of foodborne diseases on public health and economies has often been underestimated due to underreporting and difficulty to establish causal relationships between food contamination and resulting illness or death.
2015 WHO report on the estimates of the global burden of foodborne diseases presented the first-ever estimates of the disease burden caused by 31 foodborne agents (bacteria, viruses, parasites, toxins, and chemicals) at global and sub-regional levels, highlighting that more than 600 million cases of foodborne illnesses and 420 000 deaths could occur in a year. The burden of foodborne diseases falls disproportionately on groups in vulnerable situations and especially on children under 5, with the highest burden in low- and middle-income countries.
The 2019 World Bank report on the economic burden of foodborne diseases indicated that the total productivity loss associated with foodborne diseases in low- and middle-income countries was estimated at US$ 95.2 billion per year, and the annual cost of treating foodborne illnesses is estimated at US$ 15 billion.
The evolving world
Safe food supplies support national economies, trade, and tourism, contribute to food and nutrition security, and underpin sustainable development.
Urbanization and changes in consumer habits have increased the number of people buying and eating food prepared in public places. Globalization has triggered growing consumer demand for a wider variety of foods, resulting in an increasingly complex and longer global food chain. Climate change is also predicted to impact food safety.
These challenges put greater responsibility on food producers and handlers to ensure food safety. Local incidents can quickly evolve into international emergencies due to the speed and range of product distribution.
A public health priority
Governments should make food safety a public health priority, as they play a pivotal role in developing policies and regulatory frameworks and establishing and implementing effective food safety systems. Food handlers and consumers need to understand how to safely handle food and practice the WHO Five keys to safer food at home, or when selling at restaurants or local markets. Food producers can safely grow fruits and vegetables using the WHO Five keys to growing safer fruits and vegetables.
WHO aims to strengthen national food control systems to facilitate global prevention, detection, and response to public health threats associated with unsafe food. To do this, WHO supports the Member States by:
- providing independent scientific assessments on microbiological and chemical hazards that form the basis for international food standards, guidelines, and recommendations, known as the Codex Alimentarius;
- assessing the performance of national food control systems throughout the entire food chain, identifying priority areas for further development, and measuring and evaluating progress over time through the FAO/WHO food control system assessment tool;
- assessing the safety of new technologies used in food production, such as genetic modification, cultivated food products, and nanotechnology;
- helping implement adequate infrastructure to manage food safety risks and respond to food safety emergencies through the International Food Safety Authorities Network (INFOSAN);
- promoting safe food handling through systematic disease prevention and awareness programs, through the WHO Five keys to safer food message and training materials;
- advocating for food safety as an important component of health security and for integrating food safety into national policies and programs in line with the International Health Regulations (IHR 2005);
- monitoring regularly the global burden of foodborne and zoonotic diseases at national, regional, and international levels, and supporting countries to estimate the national burden of foodborne diseases; and
- updating the WHO Global Strategy for Food Safety (2022–2030) to support the Member States to strengthen their national food control systems and reduce the burden of foodborne diseases.
Following four simple steps at home—Clean, Separate, Cook, and Chill—can help protect you and your loved ones from food poisoning.
- Germs that cause food poisoning can survive in many places and spread around your kitchen.
- Wash your hands for at least 20 seconds with soap and warm or cold water before, during, and after preparing food and before eating.
- Always wash hands after handling uncooked meat, chicken, and other poultry, seafood, flour, or eggs.
- Wash your utensils, cutting boards, and countertops with hot, soapy water after preparing each food item.
- Rinse fresh fruits and vegetables under running water.
- Raw meat, poultry, seafood, and eggs can spread germs to ready-to-eat food unless you keep them separate.
- When grocery shopping, keep raw meat, poultry, seafood, and juices away from other foods.
- Keep raw or marinating meat, poultry, seafood, and eggs separate from all other foods in the refrigerator. Store raw meat, poultry, and seafood in sealed containers or packages so the juices don’t leak onto other foods.
- Use one cutting board or plate for raw meat, poultry, and seafood and a separate cutting board or plate for produce, bread, and other foods that won’t be cooked.
- Do not wash raw meat, poultry, or eggs. Washing these foods can spread germs because juices may splash onto your sink or counters.
Food is safely cooked when the internal temperature gets high enough to kill germs that can make you sick. The only way to tell if food is safely cooked is to use a food thermometer. You can’t tell if food is safely cooked by checking its color and texture (except for seafood).
- Use a food thermometer to ensure foods are cooked to a safe internal temperature. Learn how to place the thermometer correctly in different food to get an accurate reading.
- Whole cuts of beef, veal, lamb, and pork, including fresh ham: 145°F (then allow the meat to rest for 3 minutes before carving or eating)
- Fish with fins: 145°F or cook until the flesh is opaque and separates easily with a fork
- Ground meats, such as beef and pork: 160°F
- All poultry, including ground chicken and turkey: 165°F
- Leftovers and casseroles: 165°F
- Check this chart for a detailed list of temperatures and foods, including shellfish and precooked ham.
- Microwave food thoroughly: Follow recommended cooking and standing times. Letting food sit for a few minutes after microwaving allows cold spots to absorb heat from hotter areas and cook more completely.
- Know your microwave’s wattage. Check inside the door, owner’s manual, or manufacturer’s website. If your microwave is high wattage (800 watts or more), use the minimum cooking time recommended. If it is low wattage (300–500 watts), use the maximum cooking time recommended.
- When reheating, use a food thermometer to make sure that microwaved food reaches 165°F.
Bacteria can multiply rapidly if left at room temperature or in the “Danger Zone” between 40°F and 140°F.
- Keep your refrigerator at 40°F or below and your freezer at 0°F or below, and know when to throw food out before it spoils. If your refrigerator doesn’t have a built-in thermometer, keep an appliance thermometer inside it to check the temperature.
- Package warm or hot food into several clean, shallow containers and then refrigerate. It is okay to put small portions of hot food in the refrigerator since they will chill faster.
- Refrigerate perishable food (meat, seafood, dairy, cut fruit, some vegetables, and cooked leftovers) within 2 hours. If the food is exposed to temperatures above 90°F, like a hot car or picnic, refrigerate it within 1 hour.
- Thaw frozen food safely in the refrigerator, in cold water, or the microwave. Never thaw food on the counter because bacteria multiply quickly in the parts of the food that reach room temperature.
WHO works closely with Food and Agriculture Organization (FAO), the World Organization for Animal Health (OIE), The UN Environment Program (UNEP), and other international organizations to ensure food safety along the entire food chain from production to consumption.