The Online Encyclopedia and Dictionary







Food from plant sources
Food from plant sources

Food is any substance normally eaten or drunk by living organisms. The term food also includes liquid drinks. Food is the main source of energy and of nutrition for animals, and is usually of animal or plant origin.

The study of food is called food science. In English, the term food is often used metaphorically or figuratively, as in food for thought.


Legal definition

Western food law recognises four categories of object as food:

  • any substance or product, whether processed, partially processed or unprocessed, intended to be, or reasonably expected to be ingested by humans whether of nutritional value or not;
  • water and other drinks;
  • chewing gum;
  • articles and substances used as an ingredient or component in the preparation of food.

Links to official legal definitions of food:

Human eating habits

Historical development

Humans are omnivorous animals that can consume both plant and animal products. We changed from gatherers to hunter gatherers. After the experience of the ice age it is probable that humans wanted to create some feeling of security by controlling what plants were growing and which animals were available. This led to agriculture, which has continually improved and altered the way in which food is obtained.


A selection of different foods, possibly complementary, eaten together comprises a meal. People often choose to eat meals together with other family members or friends and this is seen as an important social occasion. Food eaten in smaller quantities between meals is regarded as snack food.

The number of meals in a day, their size, composition, when and how they are prepared and eaten vary greatly around the world. This is greatly dependent on the local climate, ecology, economy, cultural traditions and industrialisation. Meals also plays an important role in the celebration of many key cultural and religious festivals.

In societies where the availability of food has risen above subsistence levels and beyond staple foods, food is also sold pre-prepared for immediate consumption in restaurants and other similar retail premises. In industrial societies, meals often contain a higher proportion of food of animal origin.

See also: Appetite, Buddhist cuisine, Eucharist, Fast food, Fasting, Gault Millau restaurant guide, Halaal, I-tal, Kashrut, Michelin restaurant guide, Muslim dietary laws, Potluck, Totemism.

Food production or acquisition

Food is traditionally obtained through farming, ranching, and fishing, with hunting, foraging and other methods of subsistence locally important for some populations, but minor for others.

In the modern era, in developed nations, food supply is increasingly dependent upon agriculture, industrial farming, aquaculture and fish farming techniques which aim to maximise the amount of food produced, whilst minimising the cost. These include a reliance on mechanised tools which have been developed, from the threshing machine, seed drill, through to the tractor and combine, etc. These have been combined with the use of pesticides to promote high crop yields and combat those insects or mammals which reduce yield.

More recently, there has been a growing trend towards more Sustainable agricultural practices. This approach - which is partly fuelled by consumer demand - encourages biodiversity, local self-reliance and Organic farming methods.

Major influences on food production are international policy, e.g. the World Trade Organization and Common Agricultural Policy, national government policy or law and war.

Food for livestock is fodder and traditionally comprises hay or grain.

See also: mariculture, horticulture, agribusiness, gardening.

From plants

From animals

From neither animals or plants

Food preparation

Whilst some food can be eaten without preparation, many foods undergo some form of preparation for reasons of safety, palatability, or flavor. At the simplest level this may involve washing, cutting, trimming or adding other foods or ingredients, such as spices. It may also involve mixing, heating or cooling, pressure cooking, fermentation, or combination with other food. Most food preparation takes place in a kitchen.

The preparation of animal-based food will usually involve slaughter, evisceration, hanging, portioning and rendering.

See also: Barbecue, Eating utensils, Frankfurt kitchen, Hangi, Oven, Microwave oven, Refrigeration, Food preparation utensils.



Food manufacture

Early food processing techniques were limited by the available food preservation, packaging and transportation. In the main early food processing involved salting, curing, curdling, drying, pickling and smoking. An early processed food product was cheese.

During the industrialisation era in the 19th century, food manufacturing arose. This development took advantage of new mass markets and emerging new technology, such as milling , preservation, packaging and labelling and transportation. It brought the advantages of pre-prepared time saving food to the bulk of ordinary people who did not employ domestic servants .

At the start of the 21st century, a two-tier structure has arisen, with a few international food processing giants controlling a wide range of well known food brands; with a populous number of small local or national food processing companies.

See also: Best before, Canning, Coloring, Food quality, Snap freezing, Additives, Flavoring, Enzymes, Genetically modified food, Pasteurization, Shelf-life, Ultra-high temperature processing.

Types of manufactured food

Food trade

Food is now traded on a global basis. The variety and availability of food is no longer restricted by the diversity of locally grown food or the limitations of the local growing season. Between 1961 and 1999 there has been a 400% increase in worldwide food exports. Some countries are now economically dependent on food exports, which in some cases account for over 80% of all exports.

In 1994 trade liberalisation began when over 100 countries became signatories to the Uruguay Round of the General Agreement on Tariffs and Trade which included an agreement to reduce subsidies paid to farmers. This is underpinned by the WTO enforcement of agricultural subsidy, tariffs, import quotas and settlement of trade disputes that cannot be bilaterally resolved. Where trade barriers are raised on the disputed grounds of public health and safety, the WTO refer the dispute to the Codex Alimentarius Commission, which was founded in 1962 by the United Nations Food and Agriculture Organization and the World Health Organization.

Food retailing

Supermarket goods
Supermarket goods

The sale of surplus food traditionally took place once a week when farmers took their wares on market day, into the local village market place. Here food was sold to grocers for sale in their local shops for purchase by local people.

With the onset of industrialisation, and the development of the food processing industry, a wider range of food could be sold and distributed in distant locations. Typically early grocery shops would be counter-based shops, in which purchasers told the shop-keeper what they wanted, so that the shop-keeper could get it for them.

In the 20th century supermarkets were born. Supermarkets brought with them a self-service approach to shopping using shopping carts (or Trollies in British English) and were able to offer quality food at lower cost, through economies of scale and reduced staffing costs. This was sometimes known as 'pile it high ' In the latter part of the 20th century, this has been further revolutionised by the development of vast warehouse sized out-of-town supermarkets, selling an extraordinarily wide range of food from around the world.

Unlike food processors, food retailing is a two-tier market in which a small number of very large companies control a large proportion of supermarkets. The supermarket giants wield great purchasing power over farmers and processors, and strong influence over consumers. Nevertheless, in 2000 only 19% of all US consumer expenditure spent on food went to farmers.

Recent technological innovations such as point of sale technology - barcodes. This allows ordering of goods and food to be driven by actual sales.

See also: Farmers' market

Food and health

Food sufficiency

Food deprivation leads to malnutrition and ultimately starvation. This is often connected with famine, which involves the absence of food in entire communities. This can have a devastating and widespread effect on human health and mortality. In 2003 it was estimated that each year, 40 million people die of hunger worldwide. Rationing is sometimes used to fairly distribute food in times of shortage, most notably during times of war.

Food deprivation is regarded as a deficit need in Maslow's hierarchy of needs.

Food aid

Food aid can benefit people suffering from a shortage of food. Conversely, badly managed food aid can cause problems by disrupting local markets, depressing crop prices and discouraging food production. Its provision, or threatened withdrawal, is sometimes used as a political tool to influence the politics of the destination country. International efforts to distribute food to the neediest countries are co-ordinated by the World Food Program.

See also: Fair trade, food security.

Food safety

Foodborne illness, commonly called "food poisoning," is caused by bacteria, toxins, viruses and prions. Food poisoning has been recognised as a disease of man since as early as Hippocrates. Murder by food poisoning was used during the Roman Empire. In the Middle Ages all Royal Courts had food tasters.

The sale of rancid, contaminated or adulterated food was commonplace until introduction of hygiene, refrigeration , and vermin controls in the 19th century. Discovery of techniques for killing bacteria using heat and other microbiological studies by scientists such as Louis Pasteur contributed to the modern sanitation standards that we enjoy today. This was further underpinned by the work of Justus von Liebig whose work led to the development of modern food storage and food preservation methods.

The two most common factors leading to cases of bacterial foodborne illness are cross-contamination of ready-to-eat food from other uncooked foods and improper temperature control.

Less commonly, acute adverse reactions can also occur if chemical contamination of food occurs, for example from improper storage, or use of non-food grade soaps and disinfectants. Food can also be adulterated by a very wide range of articles (known as 'foreign bodies') during farming, manufacture, cooking, packaging, distribution or sale. For example, pests (or their faeces), hairs, cigarette butts, wood chips, metal shards, plasters etc.

Understanding of the causes of food-borne-illnesses and more systematic techniques for their elimination has led to the development of commercial systems such as HACCP which can, if properly implemented, identify and eliminate many, but not all, possible risks. HACCP is well suited to identifying and controlling these potential food safety risks.

Food allergies

Some people have food allergies or sensitivities to foods which are otherwise wholesome to the majority of people.

The amount of the food substance required to provoke a reaction in a susceptible individual can be minute. For instance, tiny amounts of food in the air, too minute to be smelled, have been known to provoke lethal reactions in sufficiently sensitive individuals. In theory, any food may provoke a reaction, however, this most commonly involves gluten, corn, shellfish (mollusks), peanuts, and soy.

Most patients present with diarrhea after ingesting certain foodstuffs, skin symptoms (rashes), bloating, vomiting and regurgitation. The digestive complaints usually develop within half an hour of ingesting the allergen.

Rarely, food allergy can lead to anaphylactic shock: hypotension (low blood pressure) and loss of consciousness. This is a medical emergency. An allergen associated with this type of reaction is peanut, although latex products can induce similar reactions. Initial treatment is with epinephrine (adrenalin), often carried by known patients in the form of an Epi-pen.

Food allergy is thought to develop easier in patients with the atopic syndrome, a very common combination of diseases: allergic rhinitis and conjunctivitis, eczema and asthma. The syndrome has a strong inherited component; a family history of these diseases can be indicative of the atopic syndrome.

Dietary habits

Dietary habits play a significant role in the health and mortality of all humans. For example:

  • Eating disorders are a group of mental disorders that interfere with normal food consumption. They often affect people with a negative body image;
  • 13% of the world's population suffer from Iodine deficiency;
  • In 2003 it was estimated that vitamin A deficiency causes blindness in up to 500,000 children each year;
  • Vitamin C deficiency results in scurvy;
  • Calcium, Vitamin D and Phosphrous are inter-related. The consumption of each may affect the absorption of the others.
  • Kwashiorkor and marasmus are childhood disorders caused by lack of dietary protein.
  • Certain foods contain allergens which can safely be consumed by the majority by people. However, these can trigger severe illness in small proportion of susceptible people. Rarely this can trigger anaphylaxis which can be fatal.

Concerns about foodborne illness have long influenced diet. Traditionally humans have learned to avoid foods that induce acute illness. Some believe that this is the underlying rationale behind some traditional religious dietary requirements. Additionally, many people choose to forgo food from animal sources to varying degrees; see vegetarianism, veganism, fructarianism, living foods diet, and raw foodism.

The nutrient content of diets in industrialised countries contain more animal fat, sugar, energy, alcohol and less dietary fiber, carbohydrates and antidioxidants . Contemporary changes to work, family and exercise patterns, together with concerns about the effect of nutrition and obesity on human health and mortality are all having an effect on traditional eating habits. Physicians and alternative medicine practitioners may recommend changes to diet as part of their recommendations for treatment.

More recently, dietary habits have been influenced by the concerns that some people have about the chronic impact on health that arise through the consumption of genetically modified food or beef infected with Bovine spongiform encephalopathy. Further concerns about the impact of industrial farming on animal welfare, human health and the environment are also having an effect on contemporary human dietary habits. This has led to the emergence of a counterculture with a preference for organic and local food.

See also: Food faddism, Health claims on food labels, list of diets, Slow Food.

Nutrients in food

Knowledge about the nutritional components and the interactions of these components in human metabolism for an ideal diet is an expanding area of knowledge.

See also

External links

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