refrigerator |
tomato |
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top 10 words in brain distribution (in article): species century form time type style culture term foot modern |
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times more probable under refrigerator 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under tomato (words not in the model) | |
A refrigerator'" (often called a "'fridge'" for short) is a cooling appliance comprising a thermally insulated compartment and a heat pump: a mechanism to transfer heat from it to the external environment, cooling the contents to a temperature below ambient. Refrigerators are extensively used to store foods which deteriorate at ambient temperatures; spoilage from bacterial growth and other processes is much slower at low temperatures. A device described as a "refrigerator" maintains a temperature a few degrees above the freezing point of water; a similar device which maintains a temperature below the freezing point of water is called a "'freezer'". The refrigerator is a relatively modern invention among kitchen appliances. It replaced the icebox, which had been a common household appliance for almost a century and a half prior. For this reason, a refrigerator is sometimes referred to as an "icebox". Freezers keep their contents frozen. They are used both in households and for commercial use. Most freezers operate around minus 18 °C (0 °F). Domestic freezers can be included as a compartment in a refrigerator, sharing the same mechanism or with a separate mechanism, or can be standalone units. Domestic freezers are generally upright units, resembling refrigerators, or chests, resembling upright units laid on their backs. Many modern freezers come with an icemaker. Commercial fridge and freezer units, which go by many other names, were in use for almost 40 years prior to the common home models. They used toxic ammonia gas systems, making them unsafe for home use. Practical household refrigerators were introduced in 1915 and gained wider acceptance in the United States in the 1930s as prices fell and non-toxic, non-flammable synthetic refrigerants such as Freon or R-12 were introduced. It is notable that while 60% of households in the US owned a refrigerator by the 1930s, it was not until 40 years later, in the 1970s, that the refrigerator achieved a similar level of penetration in the United Kingdom. History. Before the invention of the refrigerator, icehouses were used to provide cool storage for most of the year. Placed near freshwater lakes or packed with snow and ice during the winter, they were once very common. Using the environment to cool foodstuffs is still common today. On mountainsides, runoff from melting snow higher up is a convenient way to cool drinks, and during the winter months simply placing milk outside is sufficient to greatly extend its useful life. In the 11th century, the Persian physicist and chemist, Ibn Sina (Avicenna), invented the refrigerated coil, which condenses aromatic vapours. This was a breakthrough in distillation technology and he made use of it in his steam distillation process, which requires refrigerated tubing, to produce essential oils. The first known artificial refrigeration was demonstrated by William Cullen at the University of Glasgow in 1748. Between 1805, when Oliver Evans designed the first refrigeration machine that used vapor instead of liquid, and 1902 when Willis Haviland Carrier demonstrated the first air conditioner, scores of inventors contributed many small advances in cooling machinery. In 1850 or 1851, Dr. John Gorrie demonstrated an ice maker. In 1857, Australian James Harrison introduced vapor-compression refrigeration to the brewing and meat packing industries. Ferdinand Carré of France developed a somewhat more complex system in 1859. Unlike earlier compression-compression machines, which used air as a coolant, Carré's equipment contained rapidly expanding ammonia. The absorption refrigerator was invented by Baltzar von Platen and Carl Munters in 1922, while they were still students at the Royal Institute of Technology in Stockholm, Sweden. It became a worldwide success and was commercialized by Electrolux. Other pioneers included Charles Tellier, David Boyle, and Raoul Pictet. At the start of the 20th Century, about half of households in the United States relied on melting ice (in an icebox) to keep food cold, while the remaining half had no cooled storage at all. The ice used for household storage was expensive because ice had to be cut from winter ponds (or mechanically produced), stored centrally until needed, and delivered regularly. In a few exceptional cases, mechanical refrigeration systems had been adapted by the start of the 20th century for use in the homes of the very wealthy, and might be used for cooling both living and food storage areas. One early system was installed at the mansion of Walter Pierce, an oil company executive. Marcel Audiffren of France championed the idea of a refrigerating machine for cooling and preserving foods at home. His U.S. patents, issued in 1895 and 1908, were purchased by the American Audiffren Refrigerating Machine Company. Machines based on Audiffren's sulfur dioxide process were manufactured by General Electric in Fort Wayne, Indiana and marketed by the Johns-Manville company. The first unit was sold in 1911. Audiffren machines were expensive, selling for about $1,000 — about twice as much as the cost of an automobile at that time. General Electric sought to develop refrigerators of its own, and in 1915 the first "Guardian" unit was assembled in a back yard wash house as a predecessor to the Frigidaire. In 1916 Kelvinator and Servel introduced two units among a field of competing models. This number increased to 200 by 1920. In 1918, Kelvinator had a model with automatic controls. These home units usually required the installation of the mechanical parts, motor and compressor, in the basement or an adjacent room while the cold box was located in the kitchen. There was a 1922 model that consisted of a wooden cold box, water-cooled compressor, an ice cube tray and a 9 cubic foot compartment for $714. (A 1922 Model-T Ford cost about $450.) In 1923 Frigidaire introduced the first self-contained unit. About this same time porcelain covered metal cabinets began to appear. Ice cube trays were introduced more and more during the 1920s; up to this time freezing was not a function of the modern refrigerator. The first refrigerator to see widespread use was the General Electric "Monitor-Top" refrigerator introduced in 1927. The compressor assembly, which emitted a substantial amount of heat, was placed above the cabinet, and surrounded with a decorative ring. Over 1,000,000 units were produced. As the refrigerating medium, these refrigerators used either sulfur dioxide, which is corrosive to the eyes and may cause loss of vision, painful skin burns and lesions, or methyl formate, which is highly flammable, harmful to the eyes, and toxic if inhaled or ingested. Many of these units are still functional today. These cooling systems cannot be recharged with the hazardous original refrigerants if they leak or break down. The introduction of freon expanded the refrigerator market during the 1930s, and freezer units became more common during the 1940s. Home units did not go into mass production until after WWII. The 1950s and 1960s saw technical advances like automatic defrosting and automatic ice making. Developments of the 1970s and 80s brought about more efficient refrigerators, and environmental issues banned the use of CFC (freon) refrigerants used in sealed systems. Early refrigerator models (1916 and on) featured a cold compartment for ice cube trays. Successful processing of fresh vegetables through freezing began in the late 1920s by the Postum Company (the forerunner of General Foods) which had acquired the technology when it bought the rights to Clarence Birdseye's successful fresh freezing methods. The first successful example of the benefits of frozen foods occurred when General Foods heiress Marjorie Merriweather Post (then wife of Joseph E. Davies, United States Ambassador to the Soviet Union) deployed commercial-grade freezers to Spaso House, the US Embassy in Moscow in advance of the Davies’ arrival. Post, fearful of the food processing safety observed in the USSR, then fully stocked the freezers with products from General Foods' Birdseye unit. The frozen food stores allowed the Davies to lavishly entertain and serve fresh frozen foods that would otherwise be out of season. Upon returning from Moscow, Post (who resumed her maiden name after divorcing Davies) directed General Foods to market frozen product to upscale restaurants. Introduction of home freezer units occurred in the United States in 1940, and frozen foods began to make the transition from luxury to necessity. Design. Refrigerators work by the use of heat pumps operating in a refrigeration cycle. An industrial refrigerator is simply a refrigerator used in an industrial setting, usually in a restaurant or supermarket. It may consist of either a cooling compartment only (a larger refrigerator) or a freezing compartment only (a freezer) or both. The industry sometimes refers to such units as a “cold box” or a “walk-in.” The dual compartment was introduced commercially by General Electric in 1939. The vapor compression cycle is used in most household refrigerators. In this cycle, a circulating refrigerant such as R134a enters the compressor as a low-pressure vapor at its boiling point. The vapor is compressed and exits the compressor as a superheated high-pressure vapor. The superheated vapor travels through part of the condenser which removes the superheat by cooling the vapor. The vapor travels through the remainder of the condenser and is condensed into a liquid at its boiling point. Before the refrigerant leaves the condenser it will have been subcooled (i.e. below its boiling point). The subcooled liquid refrigerant passes through the metering (or throttling) device where its pressure abruptly decreases. The decrease in pressure results in the flash evaporation and auto-refrigeration of a portion of the liquid (typically, less than half of the liquid flashes). The cold and partially vaporized refrigerant travels through the coil or tubes in the evaporator. There, a fan circulates room air across the coil or tubes, and the refrigerant is totally vaporized, extracting heat from the air which is then returned to the food compartment. The refrigerant vapor, now slightly superheated, returns to the compressor inlet to continue the thermodynamic cycle. An absorption refrigerator works differently from a compressor refrigerator, using a source of heat, such as combustion of liquefied petroleum gas, or solar thermal energy. These heat sources are much quieter than the compressor motor in a typical refrigerator. The Peltier effect uses electricity directly to pump heat; refrigerators using this effect are sometimes used for camping, or where noise is not acceptable. They are totally silent, but less energy-efficient than other methods. Other uses of an absorption refrigerator (or "chiller") would include large systems used in office buildings or complexes such as hospitals and universities. These large systems are used to chill a brine solution that is circulated through the building. Other alternatives to the vapor-compression cycle but not in current use include thermionic, vortex tube, air cycle, magnetic cooling, Stirling cycle, Malone refrigeration, acoustic cooling, pulse tube and water cycle systems. Features. Early freezer units accumulated ice crystals around the freezing units. This was a result of humidity introduced into the units when the doors to the freezer were opened. This frost buildup required periodic thawing ("defrosting") of the units to maintain their efficiency. Advances in automatic defrosting eliminating the thawing task were introduced in the 1950s. Also, early units featured freezer compartments located within the larger refrigerator, and accessed by opening the refrigerator door, and then the smaller internal freezer door; units featuring entirely separate freezer compartment were introduced in the early 1960s, becoming the industry standard by the middle of that decade. Later advances included automatic ice units and self compartmentalized freezing units. An increasingly important environmental concern is the disposal of old refrigerators- initially because of the freon coolant damaging the ozone layer, but as the older generation of refrigerators disappears it is the destruction of CFC-bearing insulation which causes concern. Modern refrigerators usually use a refrigerant called HFC-134a (1,2,2,2-tetrafluoroethane), which has no ozone layer depleting properties, in place of freon. Disposal of discarded refrigerators is regulated, often mandating the removal of doors: children playing hide-and-seek have been asphyxiated while hiding inside a discarded refrigerator. This was particularly true for the older models that had latching doors. More modern units use a magnetic door gasket to hold the door sealed but can be pushed open from the inside. This gasket was invented by a man named Herman C. Ells Sr. Who didn't want children to lose their lives. He never gained recognition for his work, being a humble man only wanting to save lives. However, children can be unwittingly harmed by hiding inside any discarded refrigerator. Types of domestic refrigerators. Domestic refrigerators and freezers for food storage are made in a range of sizes. Among the smallest is a 4 L Peltier fridge advertised as being able to hold 6 cans of beer. A large domestic fridge stands as tall as a person and may be about 1 m wide with a capacity of 600 L. Some models for small households fit under kitchen work surfaces, usually about 86 cm high. Fridges may be combined with freezers, either stacked with fridge or freezer above, below, or side by side. A fridge without a true freezer may have a small compartment to make ice. Freezers may have drawers to store food in, or they may have no divisions (chest freezers). Fridges and freezers may be free-standing, or built into a kitchen. Refrigeration units for commercial and industrial applications can be made any size, shape or style to fit customer needs. Energy efficiency. An auto-defrost unit uses a blower fan to keep moisture out of the unit. It also has a heating coil beneath the evaporator that periodically heats the freezer compartment and melts any ice buildup. Some units also have heaters in the side of the door to keep the unit from "weeping." Manual defrost units are available in used-appliance shops or by special order. Refrigerators used to consume more energy than any other home appliance, but in the last twenty years great strides have been made to make refrigerators more energy efficient. In the early 1990s a competition was held among the major manufacturers to encourage energy efficiency. Current models that are Energy Star qualified use 50 percent less energy than models made before 1993. The most energy-efficient unit made in the US is designed to run on 12 or 110 volts, and consumes about half a kilowatt-hour per day. But even ordinary units are quite efficient; some smaller units use little more than one kilowatt-hour per day. Larger units, especially those with large freezers and icemakers, may use as much as 4 kWh per day. Among the different styles of refrigerators, top-freezer models are more efficient than bottom-freezer models of the same capacity, which are in turn more efficient than side-freezer models. Models with through-the-door ice units are less efficient than those without. Dr. Tom Chalko in Australia has developed an external thermostat to convert any chest freezer into a chest fridge using only about 0.1kWh per day--the amount of energy used by a 100 watt light bulb in one hour. Scientists at Oxford University have reconstructed a refrigerator invented in 1930 by Albert Einstein in their efforts to replace current technologies with energy efficient green technology. The Einstein refrigerator operates without electricity and uses no moving parts or greenhouse gases. Impact on lifestyle. The invention of the refrigerator has allowed the modern family to purchase, store, freeze, prepare and preserve food products in a fresh state for much longer periods of time than was previously possible. For the majority of families without a sizeable garden in which to grow vegetables and raise animals, the advent of the refrigerator along with the modern supermarket led to a vastly more varied diet and improved health resulting from improved nutrition. Dairy products, meats, fish, poultry and vegetables can be kept refrigerated in the same space within the kitchen (although raw meat should be kept separate from other foodstuffs for reasons of hygiene). The refrigerator allows families to consume more salads, fresh fruits and vegetables during meals without having to own a garden or an orchard. Exotic foodstuffs from far-off countries that have been imported by means of refrigeration can be enjoyed in the home because of the availability of domestic refrigeration. The luxury of freezing allows households to purchase more foods in bulk that can be eaten at leisure while the bulk purchase provides cost savings (see economies of scale). Ice cream, a popular commodity of the 20th century, was previously only available by traveling long distances to where the product was made fresh and had to be eaten on the spot. Now it is a common food item. Ice on-demand not only adds to the enjoyment of cold drinks, but is useful in first-aid applications, not to mention cold packs that can be kept frozen for picnics or in case of emergency. Temperature zones and ratings. Some refrigerators are now divided into four zones to store different types of food: The capacity of a refrigerator is measured in either litres or cubic feet (US). Typically the volume of a combined fridge-freezer is split to 100 litres (3.53 cubic feet) for the freezer and 140 litres (4.94 cubic feet) for the refrigerator, although these values are highly variable. Temperature settings for refrigerator and freezer compartments are often given arbitrary numbers (for example, 1 through 9, warmest to coldest) by manufacturers, but generally 2 to 8 °C (36 to 46 °F) is ideal for the refrigerator compartment and -18 °C (0 °F) for the freezer. Some refrigerators require a certain external temperature (60 °F) to run properly. This can be an issue when placing a refrigerator in an unfinished area such as a garage. European freezers, and refrigerators with a freezer compartment, have a four star rating system to grade freezers. Although both the three and four star ratings specify the same minimum temperature of -18°C, only a four star freezer is intended to be used for freezing fresh food. Three (or fewer) stars are used for frozen food compartments which are only suitable for storing frozen food; introducing fresh food into such a compartment is likely to result in unacceptable temperature rises. | The Tomato'" ("Solanum lycopersicum", syn. "Lycopersicon lycopersicum" & "Lycopersicon esculentum") is an herbaceous, usually sprawling plant in the Solanaceae or nightshade family, as are its close cousins tobacco, potatoes, aubergine (eggplants), chilli peppers, and the poisonous belladonna. It is a perennial, often grown outdoors in temperate climates as an annual. Typically reaching to 1-3m (3 to 9 ft) in height, it has a weak, woody stem that often vines over other plants. The leaves are long, odd pinnate, with 5–9 leaflets on petioles, each leaflet up to long, with a serrated margin; both the stem and leaves are densely glandular-hairy. The flowers are across, yellow, with five pointed lobes on the corolla; they are borne in a cyme of 3–12 together. The tomato is native to South America and a prehistoric introduction to Central America and Southern parts of North America. Genetic evidence shows that the progenitors of tomatoes were herbaceous green plants with small green fruit with a center of diversity in the highlands of Peru. These early Solanums diversified into the ~dozen species of tomato recognized today. One species, Solanum Lycopersicum, was transported to Mexico where it was grown and consumed by prehistoric humans. The exact date of domestication is not known. Evidence supports the theory the first domesticated tomato was a little yellow fruit, ancestor of L. cerasiforme, grown by the Aztecs of Central Mexico who called it ‘xitomatl’ (pronounced zee-toe-má-tel), meaning plump thing with a navel, and later called tomatl by other Mesoamerican peoples. Aztec writings mention tomatoes were prepared with peppers, corn and salt, likely to be the original salsa recipe. Some believe Spanish explorer Cortez may have been the first to transfer the small yellow tomato to Europe after he captured the Aztec city of Tenochtítlan in 1521, now Mexico City. Yet others believe Christopher Columbus, an Italian working for the Spanish monarchy, discovered the tomato earlier in 1493. The earliest discussion of the tomato in European literature appeared in an herbal written in 1544 by Pietro Andrea Mattioli, an Italian physician and botanist, who named it pomi d’oro, golden apple. The word "tomato" comes from a word in the Nahuatl language, "tomatl". The specific name, "lycopersicum", means "wolf-peach" (compare the related species "Solanum lycocarpum", whose scientific name means "wolf-fruit", common name "wolf-apple"), as they are a major food of wild canids in South America. Early history. Two modern tomato cultivar groups, one represented by the Matt's Wild Cherry tomato, the other by currant tomatoes, originate by recent domestication of the wild tomato plants apparently native to eastern Mexico. Aztecs and other peoples in the region used the fruit in their cooking; it was being cultivated in southern Mexico and probably other areas by 500BC. It is thought that the Pueblo people believed that those who witnessed the ingestion of tomato seeds were blessed with powers of divination. The large, lumpy tomato, a mutation from a smoother, smaller fruit, originated and was encouraged in Mesoamerica. Smith states this variant is the direct ancestor of some modern cultivated tomatoes. According to Andrew F Smith's "The Tomato in America", the tomato probably originated in the highlands of the west coast of South America. Smith notes there is no evidence the tomato was cultivated or even eaten in Peru before the Spanish arrived. Spanish distribution. After the Spanish colonization of the Americas, the Spanish distributed the tomato throughout their colonies in the Caribbean. They also took it to the Philippines, whence it moved to southeast Asia and then the entire Asian continent. The Spanish also brought the tomato to Europe. It grew easily in Mediterranean climates, and cultivation began in the 1540s. It was probably eaten shortly after it was introduced, and was certainly being used as food by the early 1600s in Spain. The earliest discovered cookbook with tomato recipes was published in Naples in 1692, though the author had apparently obtained these recipes from Spanish sources. However, in certain areas of Italy, such as Florence, the fruit was used solely as tabletop decoration before it was incorporated into the local cuisine in the late 17th or early 18th century. In Britain. Tomatoes were not grown in England until the 1590s, according to Smith. One of the earliest cultivators was John Gerard, a barber-surgeon. Gerard's "Herbal", published in 1597 and largely plagiarized from continental sources, is also one of the earliest discussions of the tomato in England. Gerard knew that the tomato was eaten in Spain and Italy. Nonetheless, he believed that it was poisonous (tomato leaves and stems actually contain poisonous glycoalkaloids, but the fruit is safe). Gerard's views were influential, and the tomato was considered unfit for eating (though not necessarily poisonous) for many years in Britain and its North American colonies. But by the mid-1700s, tomatoes were widely eaten in Britain; and before the end of that century, the "Encyclopædia Britannica" stated that the tomato was "in daily use" in soups, broths, and as a garnish. In Victorian times, cultivation reached an industrial scale in glasshouses, most famously in Worthing. Pressure for housing land in the 1930s to 1960s saw the industry move west to Littlehampton, and to the market gardens south of Chichester. Over the past 15 years, the British tomato industry has declined as more competitive imports from Spain and the Netherlands have reached the supermarkets. North America. The earliest reference to tomatoes being grown in British North America is from 1710, when herbalist William Salmon reported seeing them in what is today South Carolina. They may have been introduced from the Caribbean. By the mid-18th century, they were cultivated on some Carolina plantations, and probably in other parts of the Southeast as well. It is possible that some people continued to think tomatoes were poisonous at this time; and in general, they were grown more as ornamental plants than as food. Thomas Jefferson, who ate tomatoes in Paris, sent some seeds back to America. Because of their longer growing season for this heat-loving crop, several states in the US Sun Belt became major tomato-producers, particularly Florida and California. In California tomatoes are grown under irrigation for both the fresh fruit market and for canning and processing. The University of California, Davis (UC Davis) became a major center for research on the tomato. The C.M. Rick Tomato Genetics Resource Center at UC Davis is a genebank of wild relatives, monogenic mutants and miscellaneous genetic stocks of tomato. The Center is named for the late Dr. Charles M. Rick, a pioneer in tomato genetics research. Research on processing tomatoes is also conducted by the in Escalon, CA. Production trends. 125 million tons of tomatoes were produced in the world in 2005. China, the largest producer, accounted for about one quarter of the global output, followed by United States and Turkey. For processing tomatoes, California accounts for 90% of US production and 35% of world production. According to FAOSTAT, the top producers of tomatoes (in tonnes) in 2005 were: Cultivation and uses. The tomato is now grown worldwide for its edible fruits, with thousands of cultivars having been selected with varying fruit types, and for optimum growth in differing growing conditions. Cultivated tomatoes vary in size from cherry tomatoes, about the same 1–2 cm size as the wild tomato, up to beefsteak tomatoes 10 cm or more in diameter. The most widely grown commercial tomatoes tend to be in the 5–6 cm diameter range. Most cultivars produce red fruit; but a number of cultivars with yellow, orange, pink, purple, green, black, or white fruit are also available. Multicolored and striped fruit can also be quite striking. Tomatoes grown for canning are often elongated, 7–9 cm long and 4–5 cm diameter; they are known as plum tomatoes. Roma-type tomatoes are important cultivars in the Sacramento Valley where a 120-acre Morning Star cannery handles 1.2 million pounds of tomatoes an hour during the harvest season where the fields yield about 40 tons to the acre. Tomatoes are one of the most common garden fruits in the United States and, along with zucchini, have a reputation for outproducing the needs of the grower. As in most sectors of agriculture, there is increasing demand in developed countries for organic tomatoes, as well as heirloom tomatoes, to make up for flavor and texture faults in commercial tomatoes. Quite a few seed merchants and banks provide a large selection of heirloom seeds. Tomato seeds are occasionally organically produced as well, but only a small percentage of organic crop area is grown with organic seed. The definition of a heirloom tomato is vague, but unlike commercial hybrids, all are self-pollinators who have bred true for 40 years or more. Varieties. There are a great many (around 7500) tomato varieties grown for various purposes. Heirloom strains are becoming increasingly popular, particularly among home gardeners and organic producers, since they tend to produce more interesting and flavorful crops at the cost of disease resistance, and productivity. Hybrid plants remain common, since they tend to be heavier producers and sometimes combine unusual characteristics of heirloom tomatoes with the ruggedness of conventional commercial tomatoes. Tomato varieties are roughly divided into several categories, based mostly on shape and size. "Slicing" or "globe" tomatoes are the usual tomatoes of commerce; beefsteak are large tomatoes often used for sandwiches and similar applications- their kidney-bean shape makes commercial use impractical along with a thinner skin and being not bred for a long shelf life; globe tomatoes are of the category of canners used for a wide variety of processing and fresh eating; oxheart tomatoes can range in size up to beefsteaks, and are shaped like large strawberries; plum tomatoes, or paste tomatoes (including pear tomatoes), are bred with a higher solid content for use in tomato sauce and paste and are usually oblong; pear tomatoes are obviously pear shaped and based upon the San Marzano types for a richer gourmet paste; cherry tomatoes are small and round, often sweet tomatoes generally eaten whole in salads; and grape tomatoes which are a more recent introduction are smaller and oblong used in salads. Tomatoes are also commonly classified as determinate or indeterminate. Determinate, or bush, types bear a full crop all at once and top off at a specific height; they are often good choices for container growing. Determinate types are preferred by commercial growers who wish to harvest a whole field at one time, or home growers interested in canning. Indeterminate varieties develop into vines that never top off and continue producing until killed by frost. They are preferred by home growers and local-market farmers who want ripe fruit throughout the season. As an intermediate form, there are plants sometimes known as "vigorous determinate" or "semi-determinate"; these top off like determinates but produce a second crop after the initial crop. The majority of heirloom tomatoes are indeterminate, although some determinate heirlooms exist. Most modern tomato cultivars are smooth surfaced but some older tomato cultivars and most modern beefsteaks often show pronounced ribbing, a feature that may have been common to virtually all pre-Columbian cultivars. While virtually all commercial tomato varieties are red, some tomato cultivars, especially heirlooms, produce fruit in colors other than red, including yellow, orange, pink, black, brown, ivory, white, and purple, though such fruit is not widely available in grocery stores, nor are their seedlings available in typical nurseries, but must be bought as seed, often via mail-order. Less common variations include fruit with stripes (Green Zebra), fuzzy skin on the fruit (Fuzzy Peach, Red Boar), multiple colors (Hillbilly, Burracker's Favorite, Lucky Cross), etc. There is also a considerable gap between commercial and home-gardener cultivars; home cultivars are often bred for flavor to the exclusion of all other qualities, while commercial cultivars are bred for such factors as consistent size and shape, disease and pest resistance, and suitability for mechanized picking and shipping. Tomatoes grow well with 7 hours of sunlight a day. A fertilizer with the ratio 5-10-10 can be used for extra growth, but manure or compost works well too. Diseases and pests. Tomato cultivars vary widely in their resistance to disease. Modern hybrids focus on improving disease resistance over the heirloom plants. One common tomato disease is tobacco mosaic virus, and for this reason smoking or use of tobacco products are discouraged around tomatoes, although there is some scientific debate over whether the virus could possibly survive being burned and converted into smoke. Various forms of mildew and blight are also common tomato afflictions, which is why tomato cultivars are often marked with a combination of letters which refer to specific disease resistance. The most common letters are: V'" -"verticillium" wilt, F'" -"fusarium" wilt strain I, FF'" -"fusarium" wilt strain I & II, N'" -"nematodes", T'" -"tobacco mosaic virus", and A'" -"alternaria". Another particularly dreaded disease is curly top, carried by the beet leafhopper, which interrupts the lifecycle, ruining a nightshade plant as a crop. As the name implies, it has the symptom of making the top leaves of the plant wrinkle up and grow abnormally. Some common tomato pests are cutworms, tomato hornworms and tobacco hornworms, aphids, cabbage loopers, whiteflies, tomato fruitworms, flea beetles, red spider mite, slugs, and Colorado potato beetles. Pollination. In the wild, original state, tomatoes required cross-pollination; they were much more self-incompatible than domestic cultivars. As a floral device to reduce selfing, the pistils of wild tomatoes extended farther out of the flower than today's cultivars. The stamens were, and remain, entirely within the closed corolla. As tomatoes were moved from their native areas, their traditional pollinators, (probably a species of halictid bee) did not move with them. The trait of self-fertility (or self-pollenizing) became an advantage and domestic cultivars of tomato have been selected to maximize this trait. This is not the same as self-pollination, despite the common claim that tomatoes do so. That tomatoes pollinate themselves poorly without outside aid is clearly shown in greenhouse situations where pollination must be aided by artificial wind, vibration of the plants (one brand of vibrator is a wand called an "electric bee" that is used manually), or more often today, by cultured bumblebees. The anther of a tomato flower is shaped like a hollow tube, with the pollen produced within the structure rather than on the surface, as with most species. The pollen moves through pores in the anther, but very little pollen is shed without some kind of outside motion. The best source of outside motion is a sonicating bee such as a bumblebee or the original wild halictid pollinator. In an outside setting, wind or biological agents provide sufficient motion to produce commercially viable crops. Hydroponic and greenhouse cultivation. Tomatoes are often grown in greenhouses in cooler climates, and indeed there are cultivars such as the British 'Moneymaker' and a number of cultivars grown in Siberia that are specifically bred for indoor growing. In more temperate climates, it is not uncommon to start seeds in greenhouses during the late winter for future transplant. With the transplanting of tomatoes, there is a process of hardening that the plant must go through before being able to be placed outside in order to have greater survival. Hydroponic tomatoes are also available, and the technique is often used in hostile growing environments as well as high-density plantings. Picking and ripening. Tomatoes are often picked unripe (and thus colored green) and ripened in storage with ethylene. Unripe tomatoes are firm, as they ripen they soften until reaching the ripe state where they are red or orange in color and slightly soft to the touch. Ethylene is a hydrocarbon gas produced by many fruits that acts as the molecular cue to begin the ripening process. Tomatoes ripened in this way tend to keep longer but have poorer flavor and a mealier, starchier texture than tomatoes ripened on the plant. They may be recognized by their color, which is more pink or orange than the other ripe tomatoes' deep red. In 1994 Calgene introduced a genetically modified tomato called the 'FlavrSavr' which could be vine ripened without compromising shelf life. However, the product was not commercially successful (see main article for details) and was only sold until 1997. Recently, stores have begun selling "tomatoes on the vine", which are determinate varieties that are ripened or harvested with the fruits still connected to a piece of vine. These tend to have more flavor than artificially ripened tomatoes (at a price premium), but still may not be the equal of local garden produce. Slow-ripening cultivars of tomato have been developed by crossing a non-ripening cultivar with ordinary tomato cultivars. Cultivars were selected whose fruits have a long shelf life and at least reasonable flavor. Modern uses and nutrition. Tomatoes are now eaten freely throughout the world, and their consumption is believed to benefit the heart among other things. They contain lycopene, one of the most powerful natural antioxidants, which, especially when tomatoes are cooked, has been found to help prevent prostate cancer. However, other research contradicts this claim. Tomato extract branded as Lycomato is now also being promoted for treatment of high blood pressure. Lycopene has also been shown to improve the skin's ability to protect against harmful UV rays. Natural genetic variation in tomatoes and their wild relatives has given a genetic treasure trove of genes that produce lycopene, carotene, anthocyanin, and other antioxidants. Tomato varieties are available with double the normal vitamin C (Doublerich), 40 times normal vitamin A (97L97), high levels of anthocyanin (P20 Blue), and two to four times the normal amount of lycopene (numerous available cultivars with the high crimson gene). Though it is botanically a berry, a subset of fruit, the tomato is nutritionally categorized as a vegetable (see below). Since "vegetable" is not a botanical term, there is no contradiction in a plant part being a fruit botanically while still being considered a vegetable. Tomatoes are used extensively in Mediterranean cuisine, especially Italian and Middle Eastern cuisines. The tomato is acidic; this acidity makes tomatoes especially easy to preserve in home canning whole, in pieces, as tomato sauce, or paste. Tomato juice is often canned and sold as a beverage; Unripe green tomatoes can also be breaded and fried, used to make salsa, or pickled. Cultural impact===. The town of Buñol, Spain, annually celebrates La Tomatina, a festival centered on an enormous tomato fight. Tomatoes are also a popular "non-lethal" throwing weapon in mass protests; and there was a common tradition of throwing rotten tomatoes at bad performers on a stage during the 19th century; today it is usually referenced as a mere metaphor (see Rotten Tomatoes). Embracing it for this protest connotation, the Dutch Socialist party adopted the tomato as their logo. Known for its tomato growth and production, the Mexican state of Sinaloa takes the tomato as its symbol. Storage. Most tomatoes today are picked before fully ripened. They are bred to continue ripening, but the enzyme that ripens tomatoes stops working when it reaches temperatures below 12.5°C (54.5°F). Once an unripe tomato drops below that temperature, it will not continue to ripen. Once fully ripe, tomatoes can be stored in the refrigerator but are best kept a room temperature. Tomatoes stored in the refrigerator tend to lose flavor, but will still be edible; thus the "Never Refrigerate" stickers sometimes placed on tomatoes in supermarkets. Botanical description. Tomato plants are vines, initially, typically growing six feet or more above the ground if supported, although erect bush varieties have been bred, generally three feet tall or shorter. Indeterminate types are "tender" perennials, dying annually in temperate climates (they are originally native to tropical highlands), although they can live up to three years in a greenhouse in some cases. Determinate types are annual in all climates. Tomato plants are dicots, and grow as a series of branching stems, with a terminal bud at the tip that does the actual growing. When that tip eventually stops growing, whether because of pruning or flowering, lateral buds take over and grow into other, fully functional, vines. Tomato plant vines are typically pubescent, meaning covered with fine short hairs. These hairs facilitate the vining process, turning into roots wherever the plant is in contact with the ground and moisture, especially if there is some issue with the vine's contact to its original root. Most tomato plants have compound leaves, and are called regular leaf (RL) plants. But some cultivars have simple leaves known as potato leaf (PL) style because of their resemblance to that close cousin. Of regular leaves, there are variations, such as rugose leaves, which are deeply grooved, variegated, angora leaves, which have additional colors where a genetic mutation causes chlorophyll to be excluded from some portions of the leaves. Their flowers, appearing on the apical meristem, have the anthers fused along the edges, forming a column surrounded by the pistil's style. Flowers tend to be self-fertilizing. This is because they are native to the Americas, where there were no honeybees (which are native to the old world). Similarly, many plants of the Americas are self-fertilizing, while others are pollinated by flies, butterflies, moths, other insects, or other external forces that present in the Americas, that made it possible for some new world plants to originally require biotic pollination. Tomato fruit is classified as a berry. As a true fruit, it develops from the ovary of the plant after fertilization, its flesh comprising the pericarp walls. The fruit contains hollow spaces full of seeds and moisture, called locular cavities. These vary, among cultivated species, according to type. Some smaller varieties have two cavities, globe-shaped varieties typically have three to five, beefsteak tomatoes have a great number of smaller cavities, while paste tomatoes have very few, very small cavities. The seeds need to come from a mature fruit, and be dried fermented before germination. Botanical classification. In 1753 the tomato was placed in the genus "Solanum" by Linnaeus as "Solanum lycopersicum" L. (derivation, 'lyco', wolf, plus 'persicum', peach, "i.e.," "wolf-peach"). However, in 1768 Philip Miller placed it in its own genus, and he named it "Lycopersicon esculentum". This name came into wide use but was in breach of the plant naming rules. Technically, the combination "Lycopersicon lycopersicum" (L.) H.Karst. would be more correct, but this name (published in 1881) has hardly ever been used (except in seed catalogs, which frequently used it and still do). Therefore, it was decided to conserve the well-known "Lycopersicon esculentum", making this the correct name for the tomato when it is placed in the genus "Lycopersicon". However, genetic evidence ("e.g.," Peralta & Spooner 2001) has now shown that Linnaeus was correct in the placement of the tomato in the genus "Solanum", making the Linnaean name correct; if "Lycopersicon" is excluded from "Solanum", "Solanum" is left as a paraphyletic taxon. Despite this, it is likely that the exact taxonomic placement of the tomato will be controversial for some time to come, with both names found in the literature. Two of the major reasons that some still consider the genera separate are the leaf structure (tomato leaves are markedly different from any other "Solanum"), and the biochemistry (many of the alkaloids common to other "Solanum" species are conspicuously absent in the tomato). The tomato can with some difficulty be crossed with a few species of diploid Potato with viable offspring that are capable of reproducing. Such hybrids provide conclusive evidence of the close relationship between these genera. The Boyce Thompson Institute for Plant Research began sequencing the tomato genome in 2004 and is creating a database of genomic sequences and information on the tomato and related plants. A draft version of the full genome expected to be published by 2008. The genomes of its organelles (mitochondria and chloroplast) are also expected to be published as part of the project. Fruit or vegetable? Botanically, a tomato is the ovary, together with its seeds, of a flowering plant: therefore it is a fruit or, more precisely, a berry. However, the tomato is not as sweet as those foodstuffs usually called fruits and, from a culinary standpoint, it is typically served as part of a salad or main course of a meal, as are vegetables, rather than at dessert in the case of most fruits. As noted above, the term vegetable has no botanical meaning and is purely a culinary term. This argument has had legal implications in the United States. In 1887, U.S. tariff laws that imposed a duty on vegetables but not on fruits caused the tomato's status to become a matter of legal importance. The U.S. Supreme Court settled the controversy on May 10, 1893 by declaring that the tomato is a vegetable, based on the popular definition that classifies vegetables by use, that they are generally served with dinner and not dessert ("Nix v. Hedden" (149 U.S. 304)). The holding of the case applies only to the interpretation of the Tariff Act of March 3, 1883, and the court did not purport to reclassify the tomato for botanical or other purposes other than for paying a tax under a tariff act. Tomatoes have been designated the state vegetable of New Jersey. Arkansas took both sides by declaring the "South Arkansas Vine Ripe Pink Tomato" to be both the state fruit and the state vegetable in the same law, citing both its culinary and botanical classifications. In 2006, the Ohio House of Representatives passed a law that would have declared the tomato to be the official state fruit, but the bill died when the Ohio Senate failed to act on it. Tomato juice has been the official beverage of Ohio since 1965. A.W. Livingston, of Reynoldsburg, Ohio, played a large part in popularizing the tomato in the late 1800s. Due to the scientific definition of a fruit, the tomato remains a fruit when not dealing with US tariffs. Nor is it the only culinary vegetable that is a botanical fruit: eggplants, cucumbers, and squashes of all kinds (such as zucchini and pumpkins) share the same ambiguity. Pronunciation. The pronunciation of "tomato" differs in different English-speaking countries; the two most common variants are and. Speakers from the British Isles, most of the Commonwealth, and older generations among speakers of Southern American English typically say, while most American and Canadian speakers usually say. Many languages have a word that corresponds more to the former pronunciation, including the original Nahuatl word "tomato" from which they are all taken. The word's dual pronunciations were immortalized in Ira and George Gershwin's 1937 song "Let's Call the Whole Thing Off" ("You like and I like /You like and I like") and have become a symbol for nitpicking pronunciation disputes. In this capacity it has even become an American and British slang term: saying when presented with two choices can mean "What's the difference?" or "It's all the same to me." Safety. On October 30, 2006, the U.S. Centers for Disease Control and Prevention (CDC) announced that tomatoes might have been the source of a salmonella outbreak causing 172 illnesses in 18 states. The affected states included Arkansas, Connecticut, Georgia, Indiana, Kentucky, Maine, Massachusetts, Michigan, Minnesota, North Carolina, New Hampshire, Ohio, Pennsylvania, Rhode Island, Tennessee, Virginia, Vermont and Wisconsin. Tomatoes have been linked to seven salmonella outbreaks since 1990 (from the Food Safety Network). A 2008 salmonella outbreak caused the removal of tomatoes from stores and restaurants across the United States and parts of Canada. As of July 8, 2008, from April 10, 2008, the rare Saintpaul serotype of "Salmonella enterica" caused at least 1017 cases of salmonellosis food poisoning in 41 states throughout the United States, the District of Columbia, and Canada. As of July 2008, the U.S. Food and Drug Administration suspected that the contaminated food product was a common ingredient in fresh salsa, such as raw tomato, fresh jalapeño pepper, fresh serrano pepper, and fresh cilantro. It is the largest reported salmonellosis outbreak in the United States since 1985. New Mexico and Texas were proportionally the hardest hit by far, with 49.7 and 16.1 reported cases per million, respectively. The greatest number of reported cases occurred in Texas (384 reported cases), New Mexico (98), Illinois (100), and Arizona (49). There were at least 203 reported hospitalizations linked to the outbreak, it caused at least one death, and it may have been a contributing factor in at least one additional death. The CDC maintains that "it is likely many more illnesses have occurred than those reported." Applying a previous CDC estimated ratio of non-reported salmonellosis cases to reported cases (38.6:1), one would arrive at an estimated 40,273 illnesses from this outbreak. Tomato records. The heaviest tomato ever was one of 3.51 kg (7 lb 12 oz), of the cultivar 'Delicious', grown by Gordon Graham of Edmond, Oklahoma in 1986. The largest tomato plant grown was of the cultivar 'Sungold' and reached 19.8 m (65 ft) length, grown by Nutriculture Ltd (UK) of Mawdesley, Lancashire, UK, in 2000. The massive "tomato tree" growing inside the Walt Disney World Resort's experimental greenhouses in Lake Buena Vista, Florida may be the largest single tomato plant in the world. The plant has been recognized as a Guinness World Record Holder, with a harvest of more than 32,000 tomatoes and a total weight of 1,151.84 pounds (522 kg). It yields thousands of tomatoes at one time from a single vine. Yong Huang, Epcot's manager of agricultural science discovered the unique plant in Beijing, China. Huang brought its seeds to Epcot and created the specialized greenhouse for the fruit to grow. The vine grows golf ball-sized tomatoes which are served at Walt Disney World restaurants. The world record-setting tomato tree can be seen by guests along the Living With the Land boat ride at Epcot. On August 30, 2007, 40,000 Spaniards gathered in Buñol to throw of tomatoes at each other in the yearly Tomatina festival. Bare-chested tourists also included hundreds of British, French and Germans. Types. Varieties commonly grown by home gardeners include: Many varieties of processing tomatoes are grown commercially, but just five hybrid cultivars grown in California constitute over 60% of total production of processing tomatoes. Heritage and heirloom varieties with exceptional taste include: |