It takes several steps to get food from the farm or fishery to the dining table. We call these steps the food production chain (see graphic). Contamination can occur at any point along the chain—during production, processing, distribution, or preparation. Show ProductionProduction means growing the plants we harvest or raising the animals we use for food. Most food comes from domesticated animals and plants, and their production occurs on farms or ranches. Some foods are caught or harvested from the wild, such as some fish, mushrooms, and game. Production means growing the plants we harvest or raising the animals we use for food. Examples of Contamination in Production
ProcessingProcessing means changing plants or animals into what we recognize and buy as food. Processing involves different steps for different kinds of foods. For produce, processing can be as simple as washing and sorting, or it can involve trimming, slicing, or shredding. Milk is usually processed by pasteurizing it; sometimes it is made into cheese. Nuts may be roasted, chopped, or ground (such as with peanut butter). For animals, the first step of processing is slaughter. Meat and poultry may then be cut into pieces or ground. They may also be smoked, cooked, or frozen and may be combined with other ingredients to make a sausage or entrée, such as a potpie. Processing means changing plants or animals into what we recognize and buy as food. Examples of Contamination in Processing
DistributionDistribution means getting food from the farm or processing plant to the consumer or a food service facility like a restaurant, cafeteria, or hospital kitchen. This step might involve transporting foods just once, such as trucking produce from a farm to the local farmers’ market. Or it might involve many stages. For instance, frozen hamburger patties might be trucked from a meat processing plant to a large supplier, stored for a few days in the supplier’s warehouse, trucked again to a local distribution facility for a restaurant chain, and finally delivered to an individual restaurant. Distribution means getting food from the farm or processing plant to the consumer or a food service facility like a restaurant, cafeteria, or hospital kitchen. Examples of Contamination in Distribution
PreparationPreparation means getting the food ready to eat. This step may occur in the kitchen of a restaurant, home, or institution. It may involve following a complex recipe with many ingredients, simply heating and serving a food on a plate, or just opening a package and eating the food. Preparation means getting the food ready to eat. This step may occur in the kitchen of a restaurant, home, or institution. Examples of Contamination in Preparation
Mishandling at Multiple PointsSometimes, by the time a food causes illness, it has been mishandled in several ways along the food production chain. Once contamination occurs, further mishandling, such as undercooking the food or leaving it out on the counter at an unsafe temperature, can make a foodborne illness more likely. Many germs grow quickly in food held at room temperature; a tiny number can grow to a large number in just a few hours. Reheating or boiling food after it has been left at room temperature for a long time does not always make it safe because some germs produce toxins that are not destroyed by heat.
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 diarrhoea to cancers.
It also creates a vicious cycle of disease and malnutrition, particularly affecting infants, young children, elderly and the sick. Good collaboration between governments, producers and consumers is needed to help ensure food safety and stronger food
systems. Major foodborne illnesses and causesFoodborne 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. Bacteria
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 has been linked to the emergence and spread of resistant bacteria, rendering the treatment of infectious diseases ineffective in animals and humans. Viruses Some viruses can be transmitted by food consumption. Norovirus is a common cause of foodborne infections that is characterized by nausea, explosive vomiting, watery diarrhoea 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. ParasitesSome 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. PrionsPrions, 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. ChemicalsOf most concern for health are naturally occurring toxins and environmental pollutants.
The burden of foodborne diseasesThe burden of foodborne diseases to public health and to economies has often been underestimated due to underreporting and difficulty to establish causal relationships between food contamination and resulting illness or death. The 2015 WHO report on the estimates of the global burden of foodborne diseases presented the first-ever estimates of disease burden caused by 31 foodborne agents (bacteria, viruses, parasites, toxins and chemicals) at global and sub-regional level, 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 the foodborne diseases indicated that the total productivity loss associated with foodborne disease 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 and food safetySafe 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 priorityGovernments 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 practicing the WHO Five keys to safer food at home, or when selling at restaurants or at local markets. Food producers can safely grow fruits and vegetables using the WHO Five keys to growing safer fruits and vegetables. WHO responseWHO 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 Member States by:
WHO works closely with Food and Agriculture Organization (FAO), the World Organization for Animal Health (OIE), The UN Environment Programme (UNEP) and other international organizations to ensure food safety along the entire food chain from production to consumption. |