Fermented milk products

ByS.Srividh

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Introduction Dairy-all nutrients and so its very importantMilk - sterile when synthesized cow's udder some harmful to humans though the cows are not

affected and appear healthy.Some bacteria may be specifically added to milk for

fermentation to produce products like yogurt and cheese. 

Bacterial growth high numbers of bacteria in the udder and milk. Some pathogens shed through cow faeces and

contaminate the outside of the udder and teats, the farm environment (bedding, for example) and the milking equipment.

Milk - important for mammal growth and so for bacteria. bacteria grow at - body temperature (86-98°F, 30-37°C)

Fermenting Process

The processes used to turn milk into different fermented foods involves adding lactic-acid-producing microorganisms, such as bacteria and yeast, which ingest lactose, or milk sugar, and release lactic acid as waste.

This result is a rise in milk acidity, which allows the production of kefir, yogurt, cheese and sour cream among other fermented foods.

Kumis (kumiss or koumiss or kumys)  traditionally made from mare's milk. 

Kumis is a dairy product similar to kefir, but is produced from a liquid starter culture, in contrast to the solid kefir "grains". Because mare's milk contains more sugars than cow's or goat's milk, when fermented, kumis has a higher, though still mild, alcohol content compared to kefir.

Kumis is made by fermenting raw unpasteurized mare's milk over the course of hours or days, often while stirring or churning. (The physical agitation has similarities to making butter). During the fermentation, lactobacilli bacteria acidify the milk, and yeasts turn it into a carbonated and mildly alcoholic drink.

Traditionally, this fermentation took place in horse-hide containers, which might be left on the top of a yurt and turned over on occasion, or strapped to a saddle and joggled around over the course of a day's riding. Today, a wooden vat or plastic barrel may be used in place of the leather container.

Kefir Kefir is a fermented yogurt-like drink that dates back centuries to

the shepherds of the Caucasus Mountains. The word "kefir" is derived from the Turkish word “Keif,” which

means "good feeling"; a benefit this drink is said to provide for those who consume it.

Kefir is produced with starter grains, known as kefir grains, which contain active microorganisms consisting of 83 to 90 percent lactic acid bacteria and 10 to 17 percent yeast.

Kefir incorporates various essential vitamins, minerals, amino acids and enzymes, particularly phosphorus, magnesium, calcium and vitamins B2, B12, D, K and A.

Yogurt A staple of the Middle Eastern diet for thousands of

years, yogurt is a fermented food that holds the same level of protein and fat as the milk from which it is produced.

It is also a source of calcium and vitamins B2, B6 and B12.

Yogurt, like other fermented milk products, is primarily cultured from cows milk, but can be made from goat's milk.

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

Cheeses

Cheese may be the most popular fermented milk product, using more than one-third of all milk produced in the United States each year for its production.

Both soft and hard cheeses are produced by culturing milk for an extended period of time.

Certain types of cheeses can be made simply by straining the moisture out of sour cream or yogurt. Some other types of cheese, however, require additional steps in the culturing and fermentation process. Over 2,000 varieties of cheeses exist, with some of the most notable being cheddar, feta, cream, goat and blue.

Sour Cream The original process for making sour cream was to simply let cream sour on

its own. Today, a more proactive process is used: the lactic-acid-producing bacteria

Streptococcus lactis. The flavour of sour cream is mild and tangy and the texture is thick and

smooth. With a fat content somewhere between 10 to 14 percent, sour cream has significantly fewer calories than mayonnaise (a food sour cream can replace in many applications). Sour cream also works well in baking recipes for cookies cakes, breads and pies.

Filmjölk

Swedish fermented milk frequently consumed for breakfast or lunch

Filmjölk is similar to yogurt or kefir, but it is fermented using different strains of bacteria, giving it a unique flavour. 

Filmjölk is similar to yogurt or kefir, but it is fermented using different strains of bacteria, giving it a unique flavour. 

 It has a mild, slightly acidic flavour, with aromas from diacetyl and carbon dioxide. 

Traditional fermented milks of the Nordic countries are fermented at lower temperatures by mesophilic bacteria (specifically ). 

Viili  Traditional Finnish fermented milk made from unhomogenized

milk.  As the milk begins to ferment a layer of cream rises to the

surface and a surface growing mould, Geotrichum candidum, forms a thin velvety surface. 

Viili is inoculated with a starter culture containing Lacobacillus lactis subsp. cremoris that creates its ropy character. 

It is advised that viili be eaten with a tablespoon so that it can be cut into portions.  If it is mixed or eaten with a teaspoon the texture becomes ropy, making it difficult to consume. 

Viili has a mild acidic flavour and aroma with a thick consistency that maintains its shape without collapsing when placed on a plate. 

Acidophilus milk Typically a lowfat or nonfat milk to which

active cultures of Lactobacillus acidophilus have been added. 

The milk can be refrigerated to prevent further growth of the harmless bacteria producing sweet acidophilus milk. 

It can also be incubated at 38°C until a curd forms. 

 Bifidobacterium bifidum may also be included.  

Cultured Buttermilk

Traditionally butter was made by churning milk or cream, but an improved method for fermenting milk became the preferred method for cultured buttermilk production. 

Cultured buttermilk is pasteurized skim milk fermented by a lactic acid bacteria culture (Lactobacillus lactis subsp. lactis, Lactobacillus lactis subsp.cremoris, and Lactobacillus lactis subsp lactis biovar. diacetylactis, and Leuconostoc mesenteroides subsp. cremoris) and by aroma bacteria. 

It possesses a mild acid flavour with a diacetyl overtone and a smooth texture. 

Cultured buttermilk has a soft white colour and may contain added butterflakes, fruit condiments, or flavourings. 

Crème fraîche

French for fresh cream. It is mild in taste and slightly acidic, with a smooth, rich, thick

texture.  It is made in the same manner as sour cream, and used for many

of the same applications.  It is higher in fat content (usually 30-40% fat) and as a result

crème fraîche can be whisked into whipped cream. It also has a high enough fat content and low enough protein content that it can be cooked directly without curdling.  

Fermented milk products

Functional Properties Preservation: bacteria are inhibited from growing through pH reduction when

lactic acid is formed, and shelf life is increased Flavour Enhancement:  the sour characteristic of fermented milk products comes

from fermentation products (lactic acid, diactyl, carbon dioxide, ethanol); these products act as excellent flavour carriers for herbs, spices and other flavourings

Texture Enhancement: some fermented milk products (sour cream or crème fraîche) can add body and thickness to sauces, dips or vinagrettes

Reducing Caloric Content: many fermented milk products come in low fat or fat free varieties and can be used to substitute for higher fat ingredients

Emulsification: milk proteins help stabilize fat emulsions in salad dressings, soups and cakes

Foaming and Whipping: crème fraîche is capable of being whipped like whip cream

Nutritional benefits: fermented milk products may contain probiotics (bacteria that are beneficial to health) as well as many vitamins and minerals.

Pasteurization Developed by Louis Pasteur in 1860 – for wine

preservation For milk – 1895 Primary object – eliminate pathogens from milk, through

the total number of bacteria is also reduced Reduces the chances of milk spoilage Two types: Holding method : LTLT Flash method : HTST