fermented milk products.

1. MANUFACTURING OF DIFFERENT
FERMENTED MILKS AND THEIR
MICROBIOLOGICAL AND CHEMICAL
ANALYSIS.
BY:SHAILJA KUMARI
MTECH 2nd YEAR

2. HISTORY
 Louis Pasteur (1822–1895), during the 1850s and 1860s, showed that
fermentation is initiated by living organisms .
 In 1857, Pasteur showed that lactic acid fermentation is caused by living
organisms.
 In 1860, he demonstrated that bacteria cause souring in milk, his work in
identifying the role of microorganisms in food spoilage led to the process
of pasteurization.

3. FERMENTATION
 Fermentation is a metabolic process in which an organism
converts a carbohydrate such as starch and sugar into alcohol
and/or acid.
 Lactic acid fermentation is a metabolic process by
which glucose and other six carbon sugars (also, disaccharides of
six-carbon sugars, e.g. sucrose or lactose) are converted into
cellular energy and the metabolite lactate.

4. TREE OF FERMENTED MILKS

5. FERMENTED MILKS
 Fermented milk products, also known as cultured dairy
foods, cultured dairy products, or cultured milk products, are
dairy foods that have been fermented with Lactic acid bacteria such
as Lactobacillus, Lactococcus and Leuconostoc.
 The fermentation process increases the shelf-life of the product,
while enhancing the taste and improving the digestibility of milk.
 About 2.3% of the total dairy product market is in the form of
cultured dairy product.
 It has great therapeutic benefits and nutritional value.

6. COMPOSITION
The typical composition of fermented milk as per Codex
standard (243-2003) is given below :
The pH range is 3.8 – 4.6
CONSTITUENTS LEVEL (%)
Dry matter 14-18
Protein Min 2.7
Fat Less than15
Lactose 2-3
Lactic acid Min 0.3
Carbohydrates 5-25

7. FERMENTED MILK PRODUCTS
 YOGHURT
 DAHI
 KEFIR
 KUMISS
 BULGARIAN SOUR MILK
 ACIDOPHILUS MILK
 CULTURED BUTTERMILK
 CULTURED SOUR CREAM
 LEBEN
 TAETTE (SCANDINAVIAN ROPY MILK)
 SKYR
 CHEESE

8. YOGURT
 Food produced by bacterial fermentation of milk.
 Yogurt is produced using a culture of Lactobacilius delbruecki
subsp.bulgaricus and Streptococcus thermophilus bacteria.
 In mixed cultures, the final concentrations of acetaldehyde in
yogurt can range from 2.4µgg⁻¹ to 41.0 µgg⁻¹ and these levels,
along with lower amounts of acetone (1.0-4.0µgg⁻¹), acetoin (2.5-
4.0µgg⁻¹), and diacetyl (0.4-13.0µgg⁻¹ ), give yogurt its distinctive
flavor profile.
 Titratable acidity 0.7% coliform count <10/g yeast& mold count
<100/g.

9. TYPES OF YOGURT
Greek yogurt
Stirred yogurt Drinking yogurtSet yogurt
Frozen yogurt Flavoured yogurt

10. MANUFACTURE OF YOGURT

11. DAHI
 Dahi is a product made by fermenting milk of the cow or water buffalo milk with
lactic acid bacteria.
 Dahi typically contains a mixture of S. thermophilus, Lc. lactis subsp. lactis,
Lc. lactis subsp. cremoris, Lc. lactis subsp. Lactis (biovar. diacetylactis), Lb.
helveticus, Lb. casei, and Lb. acidophilus.
 The pH is 4.5–4.7. Titratable acidity 0.7% Coliform count <10/g ,
Yeast & mold count <100/g .
Constituents Level (%)
Water 85-88
Fat 5-8
Protein 3.2-3.4
Lactose 4.6-5.2
Ash 0.7-0.75
Lactic acid 0.5-1.0
Calcium 0.12-0.14
Phosphorous 0.09-0.11

12. MANUFACTURE OF DAHI
Receiving milk
Preheating (35-40˚C)
Filtration/clarification
Standardization (SNF 9-11%)
Preheating (60 ˚C)
Homogenization (176kg/sq.cm)
Pasteurization(80-90 ˚C/15-30min)
Cooling(22-25˚C)
Inoculation(1-3% lactic starter)
Packaging
Incubation(22-25 ̊ C/16-18h)
Dahi
Cooling & storage (5̊ C)

13. KEFIR
 Fermented milk drink that originated in the north Caucasus Mountains made
with kefir "grains", a yeast/bacterial fermentation starter.
 Organism- str. Lactis, beta bacterium causasicum, yeast
Lactic acid – 0.9-1%
Alcohol – 0.5-1%
Carbondioxide - 0.03-0.07%
 There are traces of acetaldehyde, diacetyl and acetoin. of the total nitrogen,7%
is in the form of peptones and 2%amino acids. Increase in vit B1, B2& Folic
acid.

14. MANUFACTURE OF KEFIR

15. KUMISS
 Kumiss is a type of fermented dairy product made from mare’s milk.
 Produced from a liquid starter culture.
 Kumiss has a higher alcohol content than kefir.
 Organism – Lactobacillus/Bacterium orienburgii, Lactobacillus bulgaricus, .
L. acidophilus, yeast
a) Lactic acid –0.7-1.8%
b) Alcohol – 1-2%
c) Carbondioxide - 0.5-0.9%
d) Ethanol – 1.3%
e) Lactose – 2.3%
f) Fat – 1.5%
g) Protein – 2.0%

16. MANUFACTURE OF KUMISS

17. BULGARIAN SOUR MILK
• Bulgarian sour milk comes under the general category of
yogurts which contain live bacteria. It is a wonderful probiotic
food.
• It is prepared – using a combination of the two strains:
Lactobacillus Bulgaricus and Streptococcus Thermophilus.

18. MANUFACTURE OF BULGARIAN SOUR MIL
Sour milk (goat or cow’s milk)
Inoculation (L.bulgaricus & S. thermophilus culture)
Ripening (40-45 ̊C)
Incubation (37 ̊C)
Acidity (1.4%)
Storage & packaging (7 ̊C)

19. ACIDOPHILUS MILK
 Milk fermented by live cultures of the bacterium acidophilus and consumed
especially to promote intestinal health.
 This cultured product is usually low in fat and has a longer shelf life than
ordinary milk.
 Acidophilus milk is usually not recommended for people who have immune
system problems.
 Lactobacillus acidophilus used as a starter culture.
 Lactic acid – 1.0% (0.6-0.7 for medicinal use) Lactobacillus counts 2000-
3000million/ml

20. MANUFACTURE OF ACIDOPHILUS MILK
Receiving milk (skim/whole/defatted)
Filtration/Clarification (35-40 ̊C)
Homogenization
Sterilization (115 ̊C/15 min)
Cooling (38 – 40 ̊C)
Inoculation (3-5 %)
Incubation (38-40 ̊C/12-16h)
Coagulation
Break-up of coagulum
Cooling (10 ̊C)
Packaging & storage (5 ̊C)

21. CULTURED BUTTERMILK
 Fermented dairy product known as cultured buttermilk is produced
from cow's milk and has a characteristically sour taste caused by lactic acid
bacteria.
 This variant is made using different strains of bacteria—either Lactococcus
lactis or Lactobacillus bulgaricus, S. lactis subsp . diacetylactis
Leuco.citrovorum which creates more tartness ,flavour and aroma.
 Acidity 0.8-0.85% LA
 Fat 0.5-3%

22. MANUFACTURE OF CULTURED BUTTERMILK
Receiving skim milk
Filtration
Pasteurization (82 – 88 ̊C/30 min)
Cooling (22 ̊C)
Inoculation (1-2%)
Incubation (21-22 ̊C)
Coagulation (12-16 h) (0.80-0.90% LA)
Creaming
Break-up of coagulum
Adding butter granules
Cooling (5-10 ̊C)
Packing & Storage (5-10 ̊C)

23. CULTURED SOUR CREAM
 It is a extremely viscous product with the flavour and aroma of butter
milk but with the fat content of 12-30%
 The starter culture Lactococcus and Leuconostoc species are used.
 The pH should be 6.2-6.3
 Sour cream typically has a clean acidic flavor with hints of diacetyl.
 It is consumed as a dressing of topping on other foods such as fruits.

24. MANUFACTURE OF CULTURED SOUR CREAM
Fortification of whole milk with cream(20% fat)
Heating(80˚C/30 min)
Homogenization (2000 psi) at 60-80˚C
Cooling (21˚C)
Inoculation (0.5-1.0 % butter starter)
Incubation(21˚C until acidity reaches 0.6%)
Cooling (5˚C)
Packaging

25. SKYR
 It is a traditional Icelandic milk product which contain 7.6% SNF, 8% sugar,
0.3% pectin, is homogenize and pasteurized at temperature 73˚C for 20 sec.
 Skim milk is fermented with S. thermophilus , L. bulgaricus , L. helveticus
lactic acid bacteria similar to those used for yogurt along with lactose-
fermenting yeasts.
 Addition of rennet. pH should be maintained 4.
Chemical composition of Skyr
Constituent Level in
Skyr Skyr whey
Dry matter % 16.72 5.66
Protein % 11.54 0.48
Fat % 0.19 -
Lactose % 4.41 4.40
Lactic acid % 1.75 0.94
Ash % 0.78 0.75

26. MANUFACTURE OF SKYR
Pasteurised skim milk
Rennet 0.01-0.1% fresh skyr (S. thermophilus + L.
bulgaricus + L. helveticus)
Fermentation(40˚C)
Acid curd(4.65)
Fermentation at 17 ˚C for 16-18h(pH4.4)
Skyr curd in whey
Heating to 67˚C/15sec
Cooling(30˚C)
Separation in a quarg separator
Whey (5% dry material)
Skyr (16-17% dry material)
Ultrafiltration (50˚C)
Retentate (16-17% dry material) Permeate
Whey drink with fruit juice

27. LEBEN
 Leben is used across the Arab World (Middle East and North Africa),to
refer to a food or beverage of fermented milk. Generally, there are two
main products known as leben: in the Levant region, yogurt; and
in Arabia and North Africa (Maghreb), buttermilk.
 There is a mixed microflora consisting of S. lactis, S. thermophilus, L.
bulgaricus and lactose fermenting yeasts.
 Labneh has 7–10% fat

28. MANUFACTURE OF LEBEN
Milk (in earthenware containers)
Inoculation with sample from previous batch
Incubation at ambient temperature until firm coagulum production
Churning with gradual addition of warm water
Heating
Butter Butter oil
Addition of
Fenugreek seeds
Leben
Cooling
Packing

29. TAETTE
 Taette is a moderately ropy and sour milk product of slightly flowing
consistency which contains not more than 0.3-0.5% of alcohol. This product
is used in Scandinavian countries in Finland.It is produced mainly by
fermenting fresh milk with a strain of S.lactis var.hollandicus and yeasts
such as Saccharomyces taette.
Composition :
a) Lactic acid – 1.0%
b) Alcohol – 0.3-0.5%
c) Acetic acid – Traces
d) CO2 - Saturation level

30. MANUFACTURE OF TAETTE
Fresh cow’s milk
Inoculation with leaves of butterwort (1%)
Addition of starter (Saccharomyces major taette,L.taette,Bacillus acidactislogus)
Maturation (2-3 days at less than 10 ̊C) in wooden cellars
‘Taette’

31. CHEESE
 Cheese is a food derived from milk that is produced in a wide range
of flavors, textures, and forms by coagulation of the milk
protein casein.
 During production, the milk is usually acidified, and adding the
enzyme rennet causes coagulation.
 Traditional pasta filata cheeses such as Mozzarella also fall into the
fresh cheese category. Fresh curds are stretched and kneaded in hot
water to form a ball of Mozzarella.
 Cheddar cheese is a relatively hard, off-white (or orange if spices
such as annatto are added), sometimes sharp-tasting (i.e., bitter),
natural cheese. Originating in the English village of Cheddar
in Somerset.

32. DIFFERENT TYPES OF CHEESE
Roquefort Feta Gouda
Mozzarella Swiss Ricotta
Cheddar Brick Parmesan

33. MANUFACTURE OF CHEESE

34. COMPOSITION OF DIFFERENT TYPES OF CHEESE
Types of cheese Moisture
%
Fat
%
Protein
%
Calcium
%
Vitamins
Vit A Thiamin Riboflavin
(µg/100g) (µg/100g) (mg/100g)
Energy
content
(Kcal/100g)
Hard
(Cheddar)
35.0 33.0 26.0 0.83 380 50 0.50 400
Semi-hard
(Edam)
43.0 24.0 26.0 0.76 250 60 0.35 320
Blue-veined
(Roquefort)
40.0 31.0 21.0 0.32 300 30 0.70 360
Soft
(Camembert)
51.0 23.0 19.0 0.39 240 50 0.45 280
Unripened
(Cottage)
79.0 0.4 16.9 0.09 3 30 0,28 82

35. MICROFLORA OF DIFFERENT CHEESE
CHEESE STARTER COMPOSITION
Cheddar S. lactis, S. cremoris, S. diacetylactis
Gouda S. lactis, S. cremoris, S. diacetylactis, Leuconostoc spp.
Cottage S. lactis, S. cremoris, Leuconostoc spp.
Swiss S. thermophilus, L. helveticus, Propionibacterium shermanii
Brick S. lactis, S. cremoris, S.thermophilus , Brevibacterium linens
Mozzarella S.thermophilus or S. faecalis & L. bulgaricus
Blue (Roquefort) S. lactis, Penicillium roqueforti
Camembert S. lactis, Penicillium camemberti

36. MICROBIAL ANALYSIS FOR DIFFERENT FERMENTED
MILK PRODUCTS
pH/Count Stirred
yogurt
Set
yogurt
Cultured
milk
Cultured
butter milk
Cultured
cream
Kefir
pH after cooling 4.0-4.2 4.2-4.4 4.3-4.5 4.4-4.6 4.4-4.7 4.4-4.3
Coliforms (per g) < 1 < 2 < 0.1-1 < 1-10 < 10 < 0.3-10
Yeasts & molds
(per g)
< 1-10 < 1-10 < 1-10 < 10 < 10 -
Others (per g) < 100-
1000
< 100 < 100 < 10-100 < 10-100 -
Salmonellae (per
25g)
< 1 < 1 - - - -
Staphylococci (per
g)
< 1 - - - - -
Enterococci - ? - - - -
Clostridia (pre g) < 1 - - - - -
B. Cereus (per g) - - < 100 - - < 100

37. CHEMICAL ANALYSIS FOR DIFFERENT
FERMENTED MILK PRODUCTS
Dahi Yogurt Kefir Kumiss Acidophilus
milk
Butter
milk
Cultured
cream
Cheese
pH 4.8 4.3 5.1-4.7 4.5-4.7 4.6 6.6-8.0 4.5-4.8 5.1-5.9
Fat% 5-8 1.7 0-4 1.5 0.5-2 0.5-3 12-30 33
Moisture
%
86 87 86.3 13.5 - - - 35
Protein% 3.2-3.4 3.5 4.5 2.0 3.9 3.3 3.1 26
Acidity% 0.5-1.1 0.7 0.9-1.1 0.7-0.9 1 0.85 0.85-1.0 -
Alcohol% - - 0.1-1.0 1-2 - - - -

38. Some other microbial and chemical
analysis
 Alfatoxin (M1) maximum level is 50ng/kg.In some cattle feed alfatoxin
(B1) is also present.
 Pesticide level: The products are contaminated with organochlorine &
organophosphorus pesticide residue with 0.094mg/kg.
 Antibiotic residue: for detection two test are performed eclipse and
biosensor test.
 Antimicrobial activity:LAB generally produce bacteriocin that has
potential of biopreservative and have bactericidal action.

39. CONCLUSION
 Chemical and microbial analysis we got to know about bacterial count
susceptible to health.
 Different microflora provide different health promoting metabolites.
 Proper manufacturing is one of important process to increase the shelf
life of different products.
 Therapeutic values such as lowering blood pressure strengthening the
vital organs and provide immunity.
 Ability to compete with normal microflora and resistance to bacteriocin,
acids and others antimicrobial agents and other inhibitory agents..
 Fermented milk products have multiple health benefits.