User:Solarys-fr/Yogurt

Yogurt

A bowl of yogurt garnished with fruit and mint
Type	Dairy product
Main ingredients	Milk, bacteria

Yogurt, 3.25% fat

Nutritional value per 100 g (3.5 oz)
Energy	257 kJ (61 kcal)
Carbohydrates	4.7 g
Sugars	4.7 g (*)
Fat	3.3 g
Saturated	2.1 g
Monounsaturated	0.9 g
Protein	3.5 g
Vitamins and minerals Vitamins Quantity %DV† Vitamin A equiv. 3% 27 μg Riboflavin (B2) 11% 0.14 mg Minerals Quantity %DV† Calcium 9% 121 mg
(*) Lactose content diminishes during storage.
†Percentages estimated using US recommendations for adults, except for potassium, which is estimated based on expert recommendation from the National Academies.

Yogurt, yoghurt, or yoghourt (/ˈjoʊɡərt/ or /ˈjɒɡət/; from Turkish: yoğurt; other spellings listed below) is a fermented milk product, produced by bacterial fermentation of milk. Yogurt contains two specific strains of live bacteria: Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. These starter cultures act symbiotically during fermentation.

The bacteria used to make yogurt are known as "yogurt cultures" and "active live cultures". Fermentation of lactose by these bacteria produces lactic acid, which acts on milk protein to give yogurt its texture and characteristic.

Cow's milk, which is available worldwide is most commonly used to make yogurt. Milk from water buffalo, goats, ewes, mares, camels, and yaks is also used to produce yogurt where available locally. Milk used may be homogenized or not (milk distributed in many parts of the world is homogenized); both types may be used but yield rather different results.

Other lactobacilli and bifidobacteria are also sometimes added during or after culturing. Some countries require yogurt to contain a certain amount of colony-forming units of microorganisms.

In the United States, some yogurts carry the National Yogurt Association's "Live and Active Culture" seal on the label, which indicates that the yogurt contains at least 108 million live starter microorganisms Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus per gram at the time of manufacture.

Definition

Yogurt is a fermented milk product, obtained from two specific strains of bacteria: Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. These starter cultures act symbiotically during fermentation.

According to the Codex Alimentarius which defines the term yogurt, "these starter microorganisms shall be viable, active and abundant in the product".

The Food and Drug Administration adds: "yogurt is the food produced by culturing one or more of the optional dairy ingredients (cream, milk, partially skimmed milk, or skim milk, used alone or in combination) with a characterizing bacterial culture that contains the lactic acid-producing bacteria, "Lactobacillus bulgaricus" and "Streptococcus thermophiles"".

The FDA says: "The food may be homogenized and shall be pasteurized or ultra-pasteurized prior to the addition of the bacterial culture."

Other dairy products are made using other bacteria, such as Lactobacillus acidophilus, Lactobacillus casei, and Bifidus.

To bear the name yogurt, the product must contain live bacteria. Some yogurts thus carry the National Yogurt Association’s "Live and Active Culture" seal. It means the yogurt contain at least 108 million live starter microorganisms Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus per gram at the time of manufacture. If these minimums are met, the "Live and Active Cultures" seal may be on the label.

Yogurt can be firm, liquid or creamy, whole or 0% fat, natural, sweetened, colored, and flavored using fruit or artificial flavoring. Yogurt is soured and thickened by adding specific lactic acid-producing cultures to milk.

According to the FDA, "yogurt, before the addition of bulky flavors, contains not less than 3.25 % milkfat and not less than 8.25 % milk solids not fat, and has a titratable acidity of not less than 0.9 %, expressed as lactic acid. Flavoring ingredients may be added after pasteurization or ultra-pasteurization. To extend the shelf life of the food, yogurt may be heat treated after culturing is completed."

Etymology and spelling

The word yogurt is derived from Turkish: yoğurt, and is usually related to the verb yoğurmak: "to be curdled or coagulated, to thicken" or yuğur- "id" and the suffix -t. The letter ğ was traditionally rendered as "gh" in transliterations of Turkish prior to 1928. In older Turkish, the letter denoted a voiced velar fricative /ɣ/, but this sound is elided between back vowels in modern Turkish, in which the word is pronounced [joˈuɾt], or [joˈɰuɾt].

In English, there are several variations of the spelling of the word, including yogurt, yoghurt and to a lesser extent yoghourt, yogourt, yaghourt, yahourth, yoghurd, joghourt, and jogourt. In the United Kingdom and Australia, yogurt and yoghurt are both current, yogurt being used by the Australian and British dairy councils, and yoghourt is an uncommon alternative. In the United States, yogurt is the usual spelling and yoghurt a minor variant. In New Zealand, yoghurt is preferred by the New Zealand Oxford Dictionary. In Canada, yogurt is most common among English speakers although yoghurt is also used, but many brands use yogourt, since it is an acceptable spelling in both English and French.

Historically there have also been cases of yogurt being spelt with a "j" instead of a "y" (e.g. jogurt and joghurt) due to alternative transliteration methods. However, there has been a decline in these variations in English speaking countries, but in certain European countries it is still commonly spelt with a "j". Most people tend to spell the word in the manner shown on the packaging of the major brands in their country.

Whatever the spelling, the word is usually pronounced with a short o /ˈjɒɡət/ in England and Wales, and with a long o /ˈjoʊɡərt/ in Scotland, North America, Australia, New Zealand, Ireland and South Africa.

History

Analysis of the L. delbrueckii subsp. bulgaricus genome indicates that the bacterium may have originated on the surface of a plant. Milk may have become spontaneously and unintentionally exposed to it through contact with plants, or bacteria may have been transferred from the udder of domestic milk-producing animals.

Yogurt has existed as far back as 10,000 B.C. in different regions all over the world and is one of the oldest foods in history. It has been a staple of the Middle Eastern diet for thousands of years.

In ancient India, the combination of yogurt and honey was called "the food of the gods" and Persian traditions used to say that "Abraham owed his fecundity and longevity to the regular ingestion of yogurt".

The cuisine of ancient Greece included a dairy product known as oxygala (οξύγαλα) which is believed to have been a form of yogurt. Galen (AD 129 – c. 200/c. 216) mentioned that oxygala was consumed with honey, similar to the way thickened Greek yogurt is eaten today.

The oldest writings that refer to yogurt are attributed to Pliny the Elder, who wrote that certain "barbarous nations" knew how "to thicken the milk into a substance with an agreeable acidity". The use of yogurt by medieval Turks is recorded in the books Diwan Lughat al-Turk by Mahmud Kashgari and Kutadgu Bilig by Yusuf Has Hajib written in the 11th century. Both texts mention the word "yogurt" in different sections and describe its use by nomadic Turks. The earliest yogurts were probably spontaneously fermented by wild bacteria in goat skin bags.

Some accounts suggest that in the 16th century, Indian emperor Akbar's cooks would flavor yogurt with mustard seeds and cinnamon. Another early account of a European introduction to yogurt is recorded in French clinical history. Francis I of France suffered from a severe diarrhea which no French doctor could cure. His ally Suleiman the Magnificent sent a doctor, who allegedly cured the patient with yogurt. Being grateful, the French king spread around the information about the food which had cured him.

Until the 1900s, yogurt was a staple in diets of people in the Russian Empire (and especially Central Asia and the Caucasus), Western Asia, South Eastern Europe/Balkans, Central Europe, and India.

Stamen Grigorov (1878–1945), a Bulgarian student of medicine in Geneva, first examined the microflora of Bulgarian yogurt. In 1905, he described it as consisting of a spherical, rod-like lactic acid that produces bacteria. In 1907, the bacterium was named Bacillus bulgaricus (now Lactobacillus delbrueckii subsp. bulgaricus).

The Russian Nobel laureate and biologist Ilya Ilyich Mechnikov (also known as Élie Metchnikoff), who worked at the Pasteur Institute in Paris (France), was influenced by Grigorov's work and hypothesized that regular consumption of yogurt was responsible for the unusually long lifespans of Bulgarian peasants. Believing Lactobacillus to be essential for good health, Mechnikov spent his rest of his life to popularize yogurt as a foodstuff throughout Europe.

Isaac Carasso industrialized the production of yogurt. In 1919, Carasso, who was from Ottoman Salonika, started a small yogurt business in Barcelona, Spain, and named it Danone ("little Daniel") after his son. The brand later expanded to other continents, and to the United States under an Americanized version of the name: Dannon.

Yogurt was introduced to the United States in the first decade of the twentieth century, influenced by Élie Metchnikoff's The Prolongation of Life; Optimistic Studies (1908); it was available in tablet form for those with digestive intolerance and for home culturing. It was popularized by John Harvey Kellogg at the Battle Creek Sanitarium, where it was used both orally and in enemas and later by Armenian immigrants Sarkis and Rose Colombosian, who started "Colombo and Sons Creamery" in Andover, Massachusetts in 1929. Colombo Yogurt was originally delivered around New England in a horse-drawn wagon inscribed with the Armenian word "madzoon" which was later changed to "yogurt", the Turkish name of the product, as Turkish was the lingua franca among immigrants of the various Near Eastern ethnicities who were the main consumers at that time.

Yogurt with added fruit jam was patented in 1933 by the Radlická Mlékárna dairy in Prague.

Yogurt's popularity in the United States was enhanced in the 1950s and 1960s, when it was marketed as a health food.

By the late 20th century, yogurt had become a common American food item.

Varieties and presentation

Tzatziki is a side dish made with yogurt, popular in Greek cuisine. It is similar yet thicker than the Turkish Cacik and similar to the traditional Bulgarian milk salad.

Skyr is an Icelandic cultured dairy product, similar to strained yogurt which has been a part of Icelandic cuisine for over a thousand years. It is traditionally served cold with milk and a topping of sugar.

Cacık, a Turkish cold appetizer made from yogurt

Tarator is a cold soup made of yogurt, cucumber, dill, garlic and sunflower oil (walnuts are sometimes added) and is popular in Bulgaria.

Raita is a condiment made with yogurt and popular in India, Pakistan and Bangladesh.

Dadiah sold in Bukittinggi Market

Da-hi is a yogurt of the Indian subcontinent, known for its characteristic taste and consistency. The word da-hi appears to be derived from the Sanskrit word dadhi, one of the five elixirs, or panchamrita, often used in Hindu ritual. Dahi also has cultural symbolism in many homes in the Mithila region of Nepal and Bihar. Yogurt balances the palate across regional cuisines throughout India. In the hot and humid south, yogurt and foods made of yogurt are a staple and yogurt rice is always the last dish of the meal. Also, the primarily vegetarian population of India derives some protein from yogurt (other than lentil and beans). Sweet yogurt (meesti doi or meethi dahi) made by fermenting sweetened milk, is common in the eastern parts of India. While cows' milk is considered sacred and is currently the primary ingredient for yogurt, goat and buffalo milk were widely used in the past, and valued for the fat content (see buffalo curd). Butter and cream were made by churning the yogurt/milk.

In India and Pakistan, it is often used in cosmetics mixed with turmeric and honey. Sour yogurt, is also used as a hair conditioner by women in many parts of India and Pakistan. Dahi is also known as Mosaru (Kannada), Thayir (Tamil), Thayiru (Malayalam), doi (Assamese, Bengali), dohi (Odia), perugu (Telugu), Qәzana a pәәner (Pashto) and Dhahi or Dhaunro (Sindhi ڏهي، ڌونرو)

Raita is a yogurt-based South Asian/Indian condiment, used as a side dish. The yogurt is seasoned with coriander (cilantro), cumin, mint, cayenne pepper, and other herbs and spices. Vegetables such as cucumber and onions are mixed in, and the mixture is served chilled. Raita has a cooling effect on the palate which makes it a good foil for spicy Indian and Pakistani dishes. Raita is sometimes also referred to as dahi.

Dadiah or Dadih is a traditional West Sumatran yogurt made from water buffalo milk, fermented in bamboo tubes.

Yogurt is popular in Nepal, where it is served as both an appetizer and dessert. Locally called dahi (दही), it is a part of the Nepali culture, used in local festivals, marriage ceremonies, parties, religious occasions, family gatherings, and so on. The most famous type of Nepalese yogurt is called juju dhau, originating from the city of Bhaktapur. In Tibet, yak milk (technically dri milk, as the word yak refers to the male animal) is made into yogurt (and butter and cheese) and consumed.

In Northern Iran, Mâst Chekide is a variety of kefir yogurt with a distinct sour taste. It is usually mixed with a pesto-like water and fresh herb purée called delal. Yogurt is a side dish to all Iranian meals. The most popular appetizers are spinach or eggplant borani, Mâst-o-Khiâr with cucumber, spring onions and herbs, and Mâst-Musir with wild shallots. In the summertime, yogurt and ice cubes are mixed together with cucumbers, raisins, salt, pepper and onions and topped with some croutons made of Persian traditional bread and served as a cold soup. Ashe-Mâst is a warm yogurt soup with fresh herbs, spinach and lentils. Even the leftover water extracted when straining yogurt is cooked to make a sour cream sauce called kashk, which is usually used as a topping on soups and stews.

Matsoni is a Georgian yogurt popular in the Caucasus and Russia. It is used in a wide variety of Georgian dishes and is believed to have contributed to the high life expectancy and longevity in the country. Dannon used this theory in their 1978 TV advertisement called In Soviet Georgia where shots of elderly Georgian farmers were interspersed with an off-camera announcer intoning, "In Soviet Georgia, where they eat a lot of yogurt, a lot of people live past 100." Matsoni is also popular in Japan under the name Caspian Sea Yogurt (カスピ海ヨーグルト).

Tarator and Cacık are popular cold soups made from yogurt, popular during summertime in Albania, Azerbaijan (known as Dogramac), Bulgaria, Macedonia, Serbia and Turkey. They are made with ayran, cucumbers, dill, salt, olive oil, and optionally garlic and ground walnuts. Tzatziki in Greece and milk salad in Bulgaria are thick yogurt-based salads similar to tarator.

Khyar w Laban (cucumber and yogurt salad) is a popular dish in Lebanon and Syria. Also, a wide variety of local Lebanese and Syrian dishes are cooked with yogurt like "Kibbi bi Laban", etc.

Rahmjoghurt, a creamy yogurt with much higher fat content (10%) than many yogurts offered in English-speaking countries (Rahm is German for "cream"), is available in Germany and other countries.

Dovga, a yogurt soup cooked with a variety of herbs and rice is popular in Azerbaijan, often served warm in winter or refreshingly cold in summer.

Yogurt made with unhomogenized milk is sometimes called cream-top yogurt; a layer of cream rises to the top.

Jameed is yogurt which is salted and dried to preserve it. It is popular in Jordan.

Zabadi is the type of yogurt made in Egypt, usually from the milk of the Egyptian water buffalo. It is particularly associated with Ramadan fasting, as it is thought to prevent thirst during all-day fasting.

Sweetened and flavored yogurt

To offset its natural sourness, yogurt is also sold sweetened, flavored or in containers with fruit or fruit jam on the bottom. The two styles of yogurt commonly found in the grocery store are set type yogurt and Swiss style yogurt. Set type yogurt is when the yogurt is packaged with the fruit on the bottom of the cup and the yogurt on top. Swiss style yogurt is when the fruit is blended into the yogurt prior to packaging.

Lassi and Moru are common beverages in India. Lassi is milk that is sweetened with sugar commonly, less commonly honey and often combined with fruit pulp to create flavored lassi. Mango lassi is a western favorite, as is coconut lassi. Consistency can vary widely, with urban and commercial lassis being of uniform texture through being processed, whereas rural and rustic lassi has curds in it, and sometimes has malai (cream) added or removed. Moru is a popular South Indian summer drink, meant to keep drinkers hydrated through the hot and humid summers of the South. It is prepared by considerably thinning down yogurt with water, adding salt (for electrolyte balance) and spices, usually green chilli peppers, asafoetida, curry leaves and mustard.

Large amounts of sugar – or other sweeteners for low-calorie yogurts – are often used in commercial yogurt. Some yogurts contain added starch, pectin (found naturally in fruit), and/or gelatin to create thickness and creaminess artificially at lower cost. Gelatin is a meat or fish product, therefore vegetarians should avoid products containing it. This type of yogurt is also marketed under the name Swiss-style, although it is unrelated to the way yogurt is eaten in Switzerland. Some yogurts, often called "cream line", are made with whole milk which has not been homogenized so the cream rises to the top. Fruit jam is used instead of raw fruit pieces in fruit yogurts to allow storage for weeks.

In the UK, Ireland, France and United States, sweetened, flavored yogurt is the most popular type, typically sold in single-serving plastic cups. Common flavors include vanilla, honey, and toffee, and fruit such as strawberry, cherry, blueberry, blackberry, raspberry, mango and peach. In the early twenty-first century yogurt flavors inspired by desserts, such as chocolate or cheesecake, have been available.

There is concern about the health effects of sweetened yogurt. The United Kingdom and the United States recommend different maximum amounts of daily sugar intake but in both nations many sweetened yogurts have too much.

A 150g (5oz) serving of some 0% fat yogurts can contain as much as 20g (0.7oz) of sugar - the equivalent of five teaspoons, says Action on Sugar. That is about half of a woman's daily recommended intake of added sugar, which is 50g (1.7oz). It's 70g (2.5oz) for men. (from the BBC)

The American Heart Association recommends that men eat no more than 36 grams of sugar per day, and women no more than 20. One Twinkie makes a big dent in that recommended daily max, packing 19 grams of the sweet stuff, Time reported. Many of the top-selling yogurts have even more.

Consumers wanting sweetened yogurt are advised to choose yogurt sweetened with sugar substitute and check the contents list to avoid corn syrup, high fructose corn syrup, honey, or sugar.

Strained yogurt

Main article: Strained yogurt

Use coffee filter to strain yogurt in a home refrigerator.

Strained yogurt is yogurt which has been strained through a filter, traditionally made of muslin and more recently of paper or cloth. This removes the whey, giving a much thicker consistency and a distinctive slightly tangy taste. Strained yogurt is becoming more popular with those who make yogurt at home, especially if using skimmed milk which results in a thinner consistency.

Yogurt that has been strained to filter or remove the whey is known as Labneh in Middle Eastern countries. It has a consistency between that of yogurt and cheese. It is popular for sandwiches in Arab countries. Olive oil, cucumber slices, olives, and various green herbs may be added. It can be thickened further and rolled into balls, preserved in olive oil, and fermented for a few more weeks. It is sometimes used with onions, meat, and nuts as a stuffing for a variety of pies or kibbeh (كبة) balls.

Some types of strained yogurts are boiled in open vats first, so that the liquid content is reduced. The popular East Indian dessert, a variation of traditional dahi called mishti dahi, offers a thicker, more custard-like consistency, and is usually sweeter than western yogurts.

Strained yogurt is also enjoyed in Greece and is the main component of tzatziki (from Turkish "cacık"), a well-known accompaniment to gyros and souvlaki pita sandwiches: it is a yogurt sauce or dip made with the addition of grated cucumber, olive oil, salt and, optionally, mashed garlic.

Srikhand, a popular dessert in India, is made from strained yogurt, saffron, cardamom, nutmeg and sugar and sometimes fruits such as mango or pineapple.

In North America and Britain, strained yogurt is commonly called “Greek yogurt”. Strained yogurt is sometimes marketed in North America as "Greek yogurt" and in Britain as "Greek-style yoghurt". In Britain the name "Greek" may only be applied to yogurt made in Greece

Beverages

PCC Dairy Yogurt Milk, with live cultures, made from water buffalo's cream milk Philippine Carabao Center.

Ayran. One of the popular beverages in Turkish cuisine.

Dugh ("dawghe" in Neo-Aramaic), ayran or dhallë is a yogurt-based, salty drink popular in Iran, Albania, Bulgaria, Turkey, Azerbaijan, Afghanistan, Pakistan, Bangladesh, Macedonia, Uzbekistan, Kazakhstan and Kyrgyzstan. It is made by mixing yogurt with water and (sometimes) salt. The same drink is known as doogh in Iran, in Armenia; laban ayran in Syria and Lebanon; shenina in Iraq and Jordan; laban arbil in Iraq; majjiga (Telugu), majjige (Kannada), and moru (Tamil and Malayalam) in South India; namkeen lassi in Punjab and all over Pakistan. A similar drink, doogh, is popular in the Middle East between Lebanon, Iran, and Iraq; it differs from ayran by the addition of herbs, usually mint, and is sometimes carbonated, commonly with carbonated water.

Borhani (or Burhani) is a spicy yogurt drink popular in Bangladesh and parts of Bengal. It is usually served with kacchi biryani at weddings and special feasts. Key ingredients are yogurt blended with mint leaves (mentha), mustard seeds and black rock salt (Kala Namak). Ground roasted cumin, ground white pepper, green chili pepper paste and sugar are often added.

Lassi (Hindi: लस्सी, Urdu: لسی) is a yogurt-based beverage originally from the Indian subcontinent that is usually slightly salty or sweet. Lassi is a staple in Punjab. In some parts of the subcontinent, the sweet version may be commercially flavored with rosewater, mango or other fruit juice to create a very different drink. Salty lassi is usually flavored with ground, roasted cumin and red chilies; this savory variation may also use buttermilk, and in India is interchangeably called ghol (Bengal), mattha (North India), "majjige" (Karnataka), majjiga (Telangana & Andhra Pradesh), moru (Tamil Nadu and Kerala), Dahi paani Chalha (Odisha), tak (Maharashtra), or chaas (Gujarat). Lassi is very widely drunk in India, Pakistan, and Bangladesh. Mango Lassi is a popular drink at Indian restaurants in the US.

In Bosnia and Herzegovina, Croatia, Macedonia, Montenegro, Serbia, and Slovenia, an unsweetened and unsalted yogurt drink usually called simply jogurt is a popular accompaniment to burek and other baked goods.

Sweetened yogurt drinks are the usual form in Europe (including the UK) and the US, containing fruit and added sweeteners. These are typically called "drinking / drinkable yogurt". Popular brands and products include Yop and BioBest Smoothie.

Also available are "yogurt smoothies", which contain a higher proportion of fruit and are more like smoothies. In Ecuador, yogurt smoothies flavored with native fruit are served with pan de yuca as a common type of fast food.

Also in Turkey, yogurt soup or Yayla Çorbası is a popular way of consuming yogurt. The soup is a mix of yogurt, rice, flour and dried mint.

Greek yogurt

Greek style yogurt is nutritionally superior to regular yogurt. Six ounces of Greek style yogurt contains 16-20 grams of protein compared with 9 grams found in the same serving of regular yogurt. With double protein, this type of yogurt is recommended after a workout or for losing weight.

Greek yogurt is also creamier because it undergoes a straining process that removes much of the whey. Greek yogurt is strained three times instead of twice, giving it a creamier texture. The whey is removed in the straining process and, as a result, a serving may provide about 25 percent of a person's daily calcium needs.

Greek yogurt also has less sodium and fewer grams of sugar and carbohydrates than regular yogurt.

Plant-milk yogurt

Plant-milk yogurt

Further information: Plant milk

A variety of plant-milk yogurts appeared in the 2000s, using soy milk, rice milk, and nut milks such as almond milk and coconut milk. So far the most widely sold variety of plant milk yogurts is soy yogurt. These yogurts are suitable for vegans, people with intolerance to dairy milk, and those who prefer plant milks.

Food-processing

The processes used to turn milk into different fermented foods involves adding lactic-acid-producing microorganisms, such as bacteria and yeast, which ingest lactose and release lactic acid as waste, causing milk to curdle and form yogurt. This results in a rise in milk acidity, which allows for the production of fermented foods such as kefir, yogurt, cheese and sour cream.

During the making of yogurt, the lactose is broken down into glucose and galactose by the lactase enzyme provided by bacteria. Further processing of glucose and galactose results in the end products of lactic acid and acetaldehyde. The production of lactic acid and acetaldehyde lowers the pH of the milk, causing it to have a tart, somewhat sour taste. The lower pH also affects the casein (milk protein), causing it to coagulate and precipitate and form the solid curd that makes up yogurt. The leftover watery liquid is the whey.

Yogurt is produced from whole or skim milk of any origin (cow, buffalo, goat, sheep, yak). Milk is first standardized and pasteurized, usually to about 85 °C (185 °F), to denature the milk proteins so that they set together rather than form curds. In some places, such as parts of India and Bangladesh, the milk is boiled. After heating, the milk is allowed to cool to about 45 °C (113 °F).

The process is followed by the inoculation of starter cultures of Lactobacillus bulgaricus and Streptococcus thermophilus. The bacterial culture is mixed in, and the temperature of 45 °C is maintained for 4 to 7 hours to allow for fermentation.

Although yogurt is made by fermenting Lactobacillus bulgaricus and Streptococcus thermophilus, other lactic acid bacteria such as Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus bulgaricus, Enterococcus faecium, Streptococcus thermophilus are frequently used to give the final product unique characteristics.

However, to meet the National Yogurt Association's criteria for the "Live and active culture yogurt" seal, the finished yogurt product must contain at least 180 million live bacteria per gram at the time of manufacture, and the cultures must remain active at the end of the stated shelf life.

During fermentation, both heat treatment and acid production result in finer coagulation of casein, which may also contribute to greater protein digestibility of yogurt than of milk.

Microorganisms can also be used to ferment non-dairy milks, including coconut milk, almond milk and soy milk, into yogurt.

Yogurt may be supplemented with fruits to enhance the flavor.

Making yogurt at home

Commercially available yogurt maker

Yogurt is made by heating milk to a temperature that denaturates its proteins (scalding), essential for making yoghurt, cooling it to a temperature that will not kill the live microorganisms that turn the milk into yoghurt, inoculating certain bacteria (starter culture), usually Streptococcus thermophilus and Lactobacillus bulgaricus, into the milk, and finally keeping it warm for several hours. The milk may be held at 85 °C (185 °F) for a few minutes, or boiled (giving a somewhat different result). It must be cooled to 50 °C (122 °F) or somewhat less, typically 40–46 °C (104–115 °F). Starter culture must then be mixed in well, and the mixture must be kept undisturbed and warm for several hours, ranging from 5 to 12, with longer fermentation producing a more acid yoghurt. The starter culture may be a small amount of live yoghurt; dried starter culture is available commercially.

Home yogurt maker

Milk with a higher concentration of solids than normal milk may be used; the higher solids content produces a firmer yoghurt. Solids can be increased by adding dried milk.

The yogurt-making process provides two significant barriers to pathogen growth, heat and acidity (low pH). Both are necessary to ensure a safe product. Acidity alone has been questioned by recent outbreaks of food poisoning by E. coli O157:H7 that is acid-tolerant. E. coli O157:H7 is easily destroyed by pasteurization (heating); the initial heating of the milk kills pathogens as well as denaturing proteins. The microorganisms that turn milk into yogurt can tolerate higher temperatures than most pathogens, so that a suitable temperature not only encourages the formation of yogurt, but inhibits pathogenic microorganisms.

Once the yogurt has formed, it can, if desired, be strained to reduce the whey content and thicken it.

Nutritional value

Unstirred Turkish Süzme Yoğurt (strained yogurt), with a 10% fat content

Yogurt is nutritionally rich in protein, calcium, potassium, magnesium, phosphorus, iron, zinc and sodium. It is also a great source of vitamins such as: vitamin C, thiamin, riboflavin, iodine, niacin, vitamins A, B2, B6, B5 (pantothenic acid), B12, D, E and K and acid folate. Due to its probiotics, yogurt has nutritional benefits beyond those of milk.

A 6-ounce serving contains about 20-30 percent of the daily recommended intake of calcium. Yogurt also contains B12, which maintains red blood cells and helps keep the nervous system functioning properly. An eight-ounce serving contains 1,4 micrograms, which represents about 60 percent of what an adult needs daily.

Yogurt contains varying amounts of fat and is generally sold in the West in three fat contents: regular (3.25% milk fat), low-fat (0.5 to 2.0%) and non-fat (less than 0.5%). Some yogurts sold as "Greek-style" may contain up to 10% fat.

Yogurt generally contains the same level of protein as the milk from which it is produced. However, because of the addition of nonfat dry milk during processing and concentration, final protein content may be higher.

Proteins from yogurt are more easily digested than milk proteins, as bacterial predigestion of milk proteins in yogurt may occur. Proteins in yogurt are excellent because the nutritional value of milk proteins is well preserved during the fermentation process. Greek yogurt has up to 20 grams of protein per container, which is more than double of the protein of other yogurts.

Comparison of Whole Dairy Milk and Plain Yogurt from Whole Dairy Milk, One Cup (245 g) Each

Property	Milk	Yogurt
Calories	146	149
Total Fat	7.9 g	8.5 g
Cholesterol	24.4 mg	11 mg
Sodium	98 mg	113 mg
Total Carbohydrates	12.8 g	12 g
Protein	7.9 g	9 g
Vitamin A	249 IU	243 IU
Vitamin C	0.0 mg	1.2 mg
Vitamin D	96.5 IU	~
Vitamin E	0.1 mg	0.1 mg
Vitamin K	0.5 μg	0.5 μg
Thiamine	0.1 mg	0.1 mg
Riboflavin	0.3 mg	0.3 mg
Niacin	0.3 mg	0.2 mg
Vitamin B6	0.1 mg	0.1 mg
Folate	12.2 μg	17.2 μg
Vitamin B12	1.1 μg	0.9 μg
Choline	34.9 mg	1.0 mg
Betaine	1.5 mg	~
Water	215 g	215 g
Ash	1.7 g	1.8 g

Tilde (~) represents missing or incomplete data.

The above shows a discrepancy with respect to the amount of sodium. The increase in sodium may be explained as a result of testing the product after draining liquid whey from the yogurt thereby increasing the percentage of sodium in the final product.

Health benefits

Scientific studies show that nutrients in yogurt may be beneficial to human health.

Yogurt, like other fermented foods, helps with digestion and the absorption of nutrients. Since Elie Metchnikoff's work, yogurt has been used to treat diarrhea, especially in children. Yogurt helps to recover faster after diarrhea. Yogurt plays a positive role in gastrointestinal diseases, constipation, Crohn disease, irritable bowel syndrome and Helicobacter pylori infections that cause stomach ulcers. Yogurt also shows promising health benefits for colorectal cancer. Intestinal-friendly bacteria present in yogurt help to keep the colon healthy, and reduce the risk of colon cancer.

Yogurt is also recommended for consumption by lactose intolerant individuals and patients suffering from atherosclerosis.

Eating yogurt with live cultures adds healthy bacteria to the intestinal tract, and thus restores a normal gut microbiota.

Yogurt supports the immune system by reducing inflammation.

Yogurt also plays a positive role in high blood pressure, allergies, type 2 diabetes and obesity. It can help decrease the risk of osteoporosis, as it contains 20 percent more protein than milk per serving.

Other health benefits of fermented milks include reduction of "bad" cholesterol.

Yogurt is also used for treating and preventing vaginal yeast and bacteria infections, and for preventing urinary tract infections.

Probiotics

Fermented foods are also referred to as that contain probiotics. Foods with probiotics are a source of live organisms that can offer many health benefits to human body. These benefits include supporting the immune system, fighting the growth of toxic intestinal bacteria, decreasing discomfort from lactose intolerance, treating diarrhea and normalizing carcinogens in food. Many dairy products are sources of fermented foods that can help produce a healthy bacteria balance in the digestive system.

Lactose intolerance

More than half of the world's adult population is lactose intolerant. In the United States, 30 to 50 million people are lactose intolerant. Inability to digest lactose varies widely among ethnic and geographic populations. The prevalence of lactose intolerance in adults is 53% among Mexican Americans, 75% among African Americans and Native Americans, and 15% among White Americans. The prevalence among adults in South America and Africa is superior to 50% and in some Asian countries is close to 100%. In European countries, it varies from 2% in Scandinavian adults to 70% in Southern Italian adults.

Lactose is a disaccharide sugar, meaning that it contains two simple forms of sugar: glucose and galactose. The human body can't absorb lactose directly but must break it down into simple sugars into the bloodstream. The intestines produce an enzyme called lactase in order to break down lactose. People with lactose intolerance don't produce enough lactase to break down lactose and digest it properly.

Yogurt and cheese however contain less lactose than other dairy products and cause fewer symptoms.

Bacteria present in yogurt "consume" much of the lactose. When milk is fermented and becomes yogurt, the lactose is partially broken down so it becomes more digestible. The live cultures are helpful in breaking down lactose and make it easier to digest, even for people who are lactose-sensitive.

Depending on the brand, regular yogurt contains around 11 grams of lactose per 6-ounce serving, which represents at least one cup of milk a day. Greek yogurt contains from 2 to 6 grams per 6-ounce serving.

Research has shown that the majority of lactose intolerant people can consume small amounts of lactose without becoming symptomatic. People with lactose maldigestion tend to eliminate dairy foods from their diet, which may cause calcium and vitamin D deficiencies. As yogurt naturally contains lactase, it is a healthy alternative for lactose intolerant people.

Weight management

Past studies have established various health benefits of yogurt. Frequent consumption of yogurt has been associated with healthier body weight and lower body mass index.

Yogurt is a low-fat food, rich both in calcium and proteins. Calcium and protein-rich foods together appear to be a good mix for weight loss. When combined, they have been clinically proven to raise metabolic rates and improve digestion and bowel health.

Moreover, yogurt contains more calcium and protein per serving than other dairy product. Protein has been shown to be the most satiating macronutrient in a number of studies. Nine scientific studies show that yogurt consumption reduces hunger and increases fullness, due to its satiating effect. According to a study, people are less hungry and have a stronger sensation of fullness after a yogurt, than after a chocolate bar, although the snacks have the same energy content. Children who consume a lot of milk and yogurt have been shown to be also less tempted to consume energy-dense beverages.

Scientists from the University of Tennessee related long-term effects of yogurt consumption after analyzing data from 440 participants from 1991 to 2008. Three or more servings of yogurt per week was associated with a significantly lower increase in weight and waist circumference. Their study published in the International Journal of Obesity, revealed that obese adults who ate three servings of fat-free yogurt a day, as part of a reduced-calorie diet, lost 22% more weight and 61% more body fat, than a comparison group who ate just one serving of yogurt daily. Yogurt eaters also lost 81% more fat in the stomach area than the others. The average weight loss was 14 pounds. People who ate 3 yogurts a week gained 50% less weight and had a 15% lower waist size compared with those who had no yogurt in their diet. Study participants lost significant amounts of fat, especially around the waist, while maintaining lean muscle tissue.

Another study showed a correlation between increased calcium intake and lower body fat. A study presented at the annual 2007 Obesity Society meeting showed significant abdominal fat reduction after seven weeks of calcium supplementation. During the study, participants ate 3-4 servings of dairy every day. The data showed that an exercise program combined with a reduced calorie diet, and an increase in dairy consumption changed metabolism significantly enough to affect the amount of body fat burned. Researchers found that high calcium foods increase the breakdown of body fat and preserve metabolism during dieting.

Another research team analyzed data from three large cohort studies with a combined cohort of 120,000 participants who were followed for twenty years. The study revealed that yogurt consumption has a protective effect against weight gain.

In addition, the Harvard University published a study in the New England Journal of Medicine revealing that yogurt could help people maintain their weight as they age. Scientists analyzed the eating habits of more than 120,000 people. Of all the foods linked with weight loss, yogurt ranked the highest. According to the study, a healthy gut flora promoted by yogurt’s beneficial bacteria may play a role in these results. Yogurt also tends to be a staple in the diets of health-conscious people.

Regular consumption of probiotics has been shown to accelerate weight loss in women. After 12 weeks, women who took probiotics lost an average of 4,4 kg while their placebo counterparts lost 2,6 kg. By the end of the 24-week period, women who were taking probiotics had lost weight (a total of 5.2 kg) while the placebo group remained stable and maintained their initial weight loss. They also experienced a drop in the appetite-regulating hormone leptin and a decline in intestinal bacteria related to obesity.

Diabetes

According to World Health Organization, 347 million people are affected by type 2 diabetes and this will increase to 552 million people by 2030.

Three meta-analyses concluded dairy product intake is associated with a lower risk of type 2 diabetes.

The EPIC-Norfolk study which followed 25,639 men and women aged 40–79 years for 11 years, showed that people who ate low-fat fermented dairy products were 24% less likely to develop type 2 diabetes than those who didn't. Yogurt alone was associated with a 28% reduced risk. The risk reduction was seen in participants who consumed an average of 4.5 standard 125-gram pots of yogurt every week. Only low-fat, fermented dairy products were associated with the decrease in risk. Consumption of milk and of high-fat fermented products had no impact. Other forms of dairy such as milk and cheese, did not provide the same kind of protection as yogurt against the risk of diabetes. These findings suggest that the consumption of specific dairy types, in this case yogurt, may be beneficial for the prevention of diabetes, highlighting the importance of food group subtypes for public health messages.

In the 2010s, researchers at the Harvard School of Public Health pooled the results of three prospective cohort studies on dairy food intake and health from over 195,000 health professionals over several decades. Researchers found that yogurt was linked to a significantly lower risk for developing type 2 diabetes. According to them, eating one serving of yogurt a day was linked to an 18% lower risk of type 2 diabetes.

In 2014, a US study followed 200,000 people in three different analyzes. Then, scientists conducted a meta-analysis of 14 prospective cohorts with 459,790 participants. They also found that a higher intake of yogurt is associated with a reduced risk of type 2 diabetes.

Yogurt contains a specific type of vitamin K, as well as probiotics, both of which have been shown to protect against diabetes. Probiotics in yogurt may also help to improve insulin sensitivity and reduce inflammation.

It is also possible that yogurt consumption is a marker of a healthy diet and lifestyle. People who eat yogurt also eat fewer unhealthy desserts and snacks.

Inflammatory bowel disease

Inflammatory bowel diseases, which include Crohn disease and ulcerative colitis, affect the digestive tract in very different ways. Studies suggest that the gut microbiota play a crucial role in these conditions. Fermented foods such as yogurt have been shown to support and restore a healthy gut bacteria.

Yogurt contains probiotics that help the digestive system to function properly.

Probiotic yogurts can contain a variety of live active bacteria cultures that aid in digestion. Lactobacillus acidophilus is one bacterium that aids digestion in the small intestine. Lactobacillus acidophilus also produces vitamin K, which is a fat-soluble vitamin that helps the blood clot or coagulate.

Another beneficial bacteria is Bifidobacterium lactis, which improves digestive comfort. Bifidobacterium lactis helps digestion, prevents constipation and irregularity, and has been shown to reduce symptoms of irritable bowel syndrome, or IBS, according to a study published in the Journal of Digestive Disease in 2009.

Bone health

Yogurt is rich in nutrients that are essential for good bone health, including calcium, protein, vitamin D, potassium, phosphorus, and other micronutrients and macronutrients. It thus improves bone health and reduces the risk of fractures in the elderly.

Adequate dietary calcium and protein are essential to achieving optimal peak bone mass in childhood and adolescence and in preventing the bone loss that occurs in later life. Three servings of dairy per day are the recommended intake of nutrients essential for good bone health, according to dieticians.

According to researchers, milk and yogurt increase bone mineral density in the hips. A study found that people who had 2.6 servings of milk, yogurt and cheese a day had better bone density scores of the hips and spine than people who consumed smaller amounts.

Muscle strength

Muscle strength has been shown to be influenced by dietary intake, particularly of calcium, protein and vitamin D.

A serving of yogurt also helps to one recover faster after a workout. With the right ratio of protein to carbohydrates, yogurt makes an healthy post-work-out snack. Dieticians recommend to eat a serving of yogurt within 60 minutes of an extended exercise. The protein in yogurt provides the amino acids the muscles need to repair themselves, and the carbohydrates replace the muscles' energy stores, which are depleted after an intense workout.

Dental health

The lactic acid in yogurt appears to provide gum protection. Researchers recently analyzed dietary intakes from nearly 1,000 adults and found those who consumed the highest levels of dairy, specifically yogurt and yogurt-type drinks, had the healthiest gums. People who eat at least two ounces of yogurt a day have a 60% lower risk of acquiring severe periodontal disease than those who don't.

Researchers also found that eating 6 ounces of yogurt a day reduced levels of hydrogen sulphide, which is a major cause of bad breath and odor. Active bacteria present in yogurt, specifically Lactobacillus bulgaricus and Streptococcus thermophiles may have a beneficial effect in the mouth. Hydrogen sulphide levels decreased by 80% after consuming a yogurt. Levels of plaque and gingivitis were also significantly lower among yogurt eaters.

Based on studies, calcium and phosphates in yogurt help to fortify tooth enamel, keeping teeth protected and healthy. Yogurt has thus been found to fight against tooth decay and plaque build-up and to protect gums from disease, while keeping breath fresh.

Cancer

According to the National Cancer Institute, cancer of the colon is the second leading cancer in the United States. Colorectal cancer is also the second most common cause of cancer death. Risk factors include genetic, environmental and dietary factors.

Scientists have found that the active culture of Lactobacillus bacteria in yogurt helps to improve the immune system. Studies have shown that the use of yogurt in the diet triples the internal production of interferon which the immune system uses to destroy tumor cells. Yogurt consumption raises the level of natural killer cells and slows down the growth of tumor cells in the intestinal tract.

In 2011, the EPIC-Italy study followed more than 45,000 people over a 12-year period. High yogurt intake was significantly associated with decreased colon cancer risk.

In another study, researchers at the National Institute for the Study and Cure of Cancers in Milan evaluated the role of bacteria on breast cancer cells. The results showed a growth inhibition induced by the bacteria from fermented milks.

An Irish team of scientists also have found that the bifidobacteria present in yogurt naturally travels through the body and can grow inside tumors. Researchers could engineer bacteria that could pump out anti-cancer agents inside tumors, without harming healthy cells.

Diarrhea

Since the early 20th century, live bacteria such as those used for the fermentation of yogurt, have been shown to offer benefits in preventing and treating diarrhea. A recent meta-analysis found that therapy using Lactobacillus strains offers an effective means of treating acute infectious diarrhea in children. Both the duration and frequency of diarrheal episodes were reduced when compared with those of control subjects. The effect of supplementing formula with Bifidobacterium bifidum and Streptococcus thermophiles on preventing the onset of acute viral diarrhea in infants was also examined. The infants who receive the bacterial therapy developed diarrhea less than the others.

In addition, Lactobacillus acidophilus and Bifidobacterium bifidum appear to help to establish a healthier balance of bacteria in the digestive tract.

According to the International Foundation for Functional Gastrointestinal Disorders, due to its lower fiber content, yogurts help to control diarrhea.

The American Gastrointestinal Association recommends yogurt for digestive health and to ease constipation and cure other intestinal problems.

In addition, several studies investigated the effects of probiotics on diarrhea associated with the use of antibiotics. The Journal of the American Medical Association found that yogurt helps to prevent the diarrhea that often accompanies antibiotic treatment.

A team of California-based researchers combined the results of 63 randomized trials pitting probiotics versus placebo among almost 12,000 men and women taking antibiotics. Those who took antibiotics plus probiotics were 42% less likely to develop diarrhea as those who got the placebo. If diarrhea results from antibiotic use, yogurt alleviate or prevent loose stools. Antibiotics reduce the number of beneficial bacteria and other microorganisms in the intestines that help regulate stools. Yogurt may help reintroduce these microorganisms, helping to prevent this side effect.

High blood pressure

Various studies suggest that eating foods that contain probiotics, such as yogurt, sour milk and cheese, reduces high blood pressure and maintains healthy blood pressure levels.

In 2012, American researchers concluded a 14 year-study following more than 2,000 volunteers. They found that long-term yogurt eaters had lower blood pressure. People who ate one serving of yogurt every three days were 31% less likely to develop high blood pressure than others, indicating that a higher yogurt intake as part of a healthy diet, controls blood pressure and prevents hypertension.

An analysis of nine studies published in 2014 in the journal Hypertension found that probiotics tend to lower blood pressure and to maintain healthy blood pressure levels. The reduction was greatest in people who had high blood pressure and among those who consumed multiple probiotic strains. However, the benefits only applied if probiotics were eaten for more than eight weeks.

Other findings suggest that regular consumption of probiotics may control blood sugar and keep the enzymes and proteins that control blood flow and fluid volumes in check. It may also lower cholesterol levels, and therefore reduce the chances of developing hypertension. Long-term daily intake of yogurt can increase one's HDL cholesterol or "good cholesterol", while decreasing one's LDL cholesterol or "bad cholesterol".

Moreoever, a healthy gut microbiota may help to regulate hormones involved in controlling blood pressure and fluid balance in the body.

In addition, the potassium present in yogurt, almost 600 milligrams per eight ounces, may help flush some of the excess sodium out of human body, responsible for high blood pressure.

Immune system

When the digestive system is functioning properly, all the nutrients are absorbed and assimilated by the human body and the immune system is better equipped to fight against disease.

According to a study at the University of Vienna, women who eat four ounces of yogurt a day have stronger and more active T cells, which battle infection. The healthy bacteria send signals to the immune-boosting cells in human body to power up and fight off illness.

Allergy

Allergy sufferers, who typically have low levels of certain T cells, may also find relief by adding yogurt to their diets. In a study in the Journal of Nutrition, people who ate seven ounces of yogurt a day had fewer symptoms than those who ate none.

In addition, allergy sufferers who consumed Lactobacillus casei react less to pollen and other allergens.

Australian scientists have found that yogurt and fermented food may possibly cure peanut allergies. Researchers conducted a study on allergic children. 60 children were treated with increasing doses of a peanut protein over the course of 18 months. Half were also given a daily dose of a probiotic called Lactobacillus rhamnosus. Two to five weeks after the end of the treatment, each of the kids was given a peanut challenge to test their reaction. Researchers observed that 80 percent of study participants were able to eat peanuts without an allergic reaction when they took together the peanuts with yogurt.

Previous studies have shown that probiotics can fight food allergies.

Lactobacillus casei in yogurt may also decrease body levels of immune substances involved in seasonal allergies.

Gut health

Components of the human gut flora (also called "gut microbiota") may have harmful or beneficial effects on human health. Abundant evidence indicates that specific bacterial species used for the fermentation of dairy products such as yogurt have powerful antipathogenic and antiinflammatory properties. These microorganisms are involved with enhanced resistance to colonization of pathogenic bacteria in the intestine.

Others

Yeast

Yogurt may be recommended for the treatment and prevention of yeast infections. It may be eaten or applied inside the body to treat yeast infections.

Yeast infections are the result of an imbalance of the body’s acid levels (vagina's pH and yeast levels), antibiotic use, diet, diabetes, environmental factors, and raised estrogen levels from birth control or pregnancy. When the normal acidic balance is upset (pH), yeast thrives and grows. Eating yogurt or taking Lactobacillus acidophilus tablets while on antibiotics helps prevent yeast infections.

Mood

Eating yogurt regularly may positively affect brain function, according to a new study published in the journal Gastroenterology. In the four-week study, UCLA researchers observed 36 women and found that consuming probiotics helped reduce activity in several parts of the brain including the areas that monitor the mood and sensitivity to pain, anxiety and stress.

Testosterone

A recent study found mice taking probiotics had bigger testes and increased testosterone than mice who weren’t.

Nutrient density

The American diet is said to be energy-rich but nutrient-poor. Yogurt is considered nutrient dense, as it has a high nutritional value, due to its balanced nutrient profile which includes protein, carbohydrates and fats.

Yogurt contains numerous minerals, including calcium and potassium. Calcium is important for maintaining healthy bones and teeth. Potassium is important for the transmission of nerve impulses, proper muscle function. The high level of protein in yogurt makes it a good choice for vegetarians and sportsmen.

Most yogurt contains active strains of microorganisms. Probiotics, such as lactobacillus and acidophilus, are considered good bacteria because they are beneficial to human's health. Probiotics may promote the growth of healthy bacteria in the small intestine. Not all yogurt contains active cultures. "Contains active yogurt cultures" on the label prove the presence of live bacteria beneficial for health.

See also

• Fermented milk products
• Frozen yogurt
• List of dairy products
• List of yogurt-based dishes and beverages
• Matzoon
• Probiotic
• Soy yogurt

Other fermented dairy products

• Amasi
• Chal
• Curd
• Filmjölk
• Kumis
• Ryazhenka
• Shanklish
• Smetana
• Varenets
• Viili

References

• Dalby, A. Siren Feasts: A History of Food and Gastronomy in Greece. London: Routledge, 1996. ISBN 0-415-15657-2