Mechanized systems of food and fiber production used in agriculture. The mechanized systems comprising agricultural machinery are utilized in numerous aspects of agriculture, including the initial tillage of the soil (Fig. 1), planting, cultural practices during the growing season, protection from pests, harvesting, conditioning, livestock feeding, and delivery for processing. The use of hydraulic power, which offers the advantages of being easily controlled and automated, made possible highly specialized mechanisms to perform intricate operations. Modern technology has been used to increase the precision needed in modern agriculture, with examples including lasers for laying out fields for surface irrigation systems; microprocessors for sensing and controlling intricate operations, such as controlling feed mixtures for dairy cows and grading fruits and vegetables; and electronic devices in the automation of many harvesters. See also: Agricultural engineering; Agricultural science (animal); Agricultural science (plant); Agricultural soil and crop practices; Agriculture; Dairy machinery; Hydraulics; Laser; Microprocessor

The techniques and methods used in plowing, harrowing, planting, tilling, harvesting, drying, storing, and processing of agricultural crops. Agricultural soil and crop practices seek to keep the quality and fertility of soils at high levels so as to ensure the maximal productivity of crops. Various methods and approaches have been developed, starting at the advent of agricultural domestication by humans and continuing with modern technologies into the present day (Fig. 1). Farmers, agricultural engineers, agronomists, and plant biologists are all involved in the conception and implementation of agricultural soil and crop practices. See also: Agricultural engineering; Agricultural machinery; Agricultural science (plant); Agriculture; Agronomy; Domestication (anthropology); Farm crops; Precision agriculture; Soil; Soil ecology; Soil fertility

Substances suitable for the nutrition of animals, including livestock and poultry feed and pet food. Animal feed includes plant and animal products and by-products as well as vitamin and mineral supplements.

Substitutes for sugar (sucrose) in foods and beverages that provide intense sweetness with few to no calories. Artificial sweeteners are sometimes called low-calorie sweeteners, high-intensity sweeteners, noncaloric sweeteners, non-nutritive sweeteners, or intense sweeteners (see illustration). Artificial sweeteners can be used in combination with sugar or can completely replace sugar in food and beverage products. Sugar contains roughly 4 calories per gram, that is, about 16 calories per teaspoon. The average 355-ml (12-oz) soft drink contains about 140 calories from sugar, while the same-size soft drink with an artificial sweetener may contain less than 5 calories. Artificial sweeteners can be 150–20,000 times sweeter than sugar, thus requiring only small amounts of the sugar substitute to achieve the same level of sweetness in a food or beverage. If an artificial sweetener does contain calories, so little of the artificial sweetener is used that the calorie contribution to the person’s diet is almost zero. See also: Food; Food manufacturing; Sugars (sweeteners); Taste

Keeping perishable products at low temperatures to extend shelf life. Cold storage vastly retards the natural deterioration of perishable products at higher temperatures. Time and temperature are the key factors that determine how well foods (see illustration), pharmaceuticals, and many manufactured commodities can retain properties similar to those they possess at the time of harvest or manufacture. This article discusses the cold storage of food. See also: Food

Equipment used in the production and processing of milk and milk products, including milking machines, cream separators, coolers, pasteurizers, homogenizers, butter-making equipment, evaporators and dryers, and related items of equipment. Dairy machinery (Fig. 1) must be easy to clean and designed to prevent contamination of the milk or milk products from dirt, oil, soluble metals, insects, and other foreign materials.

An enzymatic transformation of organic substrates, especially carbohydrates, generally accompanied by the evolution of a gas. Fermentation is a chemical transformation of organic substrates, especially carbohydrates, to alcohol or organic acids, typically involving the production of a gas, such as carbon dioxide (CO₂) or hydrogen gas. It is a physiological counterpart of oxidation, permitting certain organisms to live and grow in the absence of air. Fermentation is used in various industrial processes for the manufacture of products such as alcohols, acids, and cheese by the action of yeasts, molds, and bacteria. The best-known example is alcoholic fermentation, in which sugar is converted into ethyl alcohol (ethanol) and carbon dioxide (Fig. 1). This conversion, chemically represented by C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂, was established by J. L. Gay-Lussac in 1815. See also: Carbon dioxide; Distilled spirits; Ethyl alcohol; Food; Food fermentation; Food manufacturing; Food microbiology; Sugars (sweeteners)

The application of engineering principles to process, store, distribute, and protect food products for human consumption. The field of food engineering is multidisciplinary in nature because it combines chemistry, physics, engineering sciences, microbiology, computer science, and automation. The end result is the delivery of safe, wholesome, and tasty foods to the consumer in a sustainable manner while minimizing wastes of energy, water, and raw materials. The principles used in food engineering also apply to many other types of industries, including pharmaceutical, cosmetics, chemical, and biotechnology. See also: Energy; Food; Water

Foods made through desired microbial growth and enzymatic conversions of food components. Well-known examples of such foods are bread, cheese, beer, wine, vinegar, some sausages, vegetables, yogurt, and cultured milk (see illustration).

A total sequence of food operations, including the growth and selection of raw materials, harvesting, processing, preservation, and distribution. In general, the aim of all food manufacturing operations is to extend the availability of seasonal crops to year-round use.