The yoghurt

Yogurt is a very ancient food. The first traces of it have been found between 10 000 and 5 000 BCE in the Neolithic period, a time when nomadic people were turning themselves to a new way of life and the beginnings of agriculture slowly led to sedentary lifestyle. At that time, the populations were also starting to domesticate animals such as cows, goats, buffalo, yaks and camels, which produced milk (2).

In the meantime, herdsmen in the Middle East used animal gut to make bags dedicated to milk transportation. Thus intestinal enzymes were in contact with milk, and may have caused it to curdle and sour. Such milk was easier to carry, and was to some extent the first yogurt. Also, these changes observed with the milk structure may have led to the understanding that a dairy product could be conserved for a relatively long period, as it is well known today.

Yogurt made its way through centuries, spreading all around the world. Yogurt was introduced into Western Europe in the 16th century by the King of France, Francois the 1st, after he was given it as a treatment for severe diarrhea, by a doctor from Turkey (3).

Before anything was known about bacteria, lactose in milk was converted to lactic acid thanks to starter cultures, thus prevent milk from pathogens. This transformation was operated by inoculating fresh milk with small amounts of sour milk. For people living in precarious conditions, such fermented dairy products were a safe habit to preserve milk.

In 1909, Nobel Prize-winner Elie Metchnikoff suggested that ageing is caused by toxic bacteria in the gut and that lactic acid could extend life.

Throughout the 20th century, yogurt began to be manufactured in order to be sold commercially. The first yogurt factory was opened in 1932, in France by Daniel Carasso. Its potential health benefits drew so much interest that yogurt was first sold in pharmacies. Today, yogurt is widely recognized as a healthy food and is still part of many diets around the world (3).

What are the different types of yogurt?

There is a lot of varieties of yogurt on the market, depending of the manufacturing procedure and ingredients, added to plain yogurt before or after fermentation:

The type of milk used (skimmed, semi-skimmed or whole), and eventually the addition of cream, will determine the final fat content of yogurt.

For stirred-style yogurt, milk is fermented into jacketed fermentation tank. After fermentation, the content is stirred. Fruit and flavor may be incorporated, then the content is cooled and products are packaged and stored at refrigeration temperatures.

For set-style yogurt, also known as French style, the milk is inoculated with ferments and added with other ingredients (fruit preparation, sugar, flavors…) before packaging. The fermentation process occurs in packages during the incubation period, after which the product is cooled and stored at refrigeration temperatures.

Drinking yogurt is stirred yogurt that has a low total solids content and which has undergone homogenization to further reduce the viscosity. Sweetener, flavoring and coloring ingredients may then be added and the product is packed in bottles.

What is Greek yogurt?

Greek yogurt is traditionally obtained by straining normal yogurt, which gives it a thicker texture.

What is Greek yogurt - YINIIt is a concentrated fermented milk as defined by Codex Alimentarius, which specifies that the protein content must be at least 5.6 g per 100 g.

During the draining process, the aqueous part of the milk – the whey or lactoserum – is removed, which explains the low lactose content of Greek yogurt.

However, to date there is no controlled denomination, either for Greek yogurt or Greek-style yogurt. Only local decrees, varying from one country to another, regulate the names. So market practices as well as the names vary between countries: Greek yogurt, Greek-style yogurt, strained yogurt, and so on.

Reading the label provides useful clarifications on the real nature of the yogurt.