This document discusses various fermented milk products including yogurt, kefir, cheese, and others. It explains that fermenting milk involves adding bacteria or yeast that consume lactose and produce lactic acid, lowering the milk's pH. This fermentation process allows the creation of products like yogurt, kefir and cheese. The document also outlines some traditional fermented milks from different cultures around the world and describes their production processes and characteristics. Finally, it discusses the functional properties and nutritional benefits of fermented milk products.

1. Fermented milk products
By
S.Srividhya

2. Introduction
 Dairy-all nutrients and so its very important
 Milk - 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.

3. 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)

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. 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.

10. 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 ).

11. 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.

12. 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.

13. 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.

14. 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.

15. Fermented milk products

17. 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.

19. 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