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PREPARATION AND PRESERVATION OF MILK PRODUCTS

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Milk • Milk is an ancient mankind itself, as it is the

substance created to feed the mammalian infant.

• Considered as the most valuable and nutritious product for the human consumption

• Most suitable and elaborate substance provided by nature

• Best nutrient medium for the growth of various organisms

• Contains proteins, fats, carbohydrates, inorganic salts and vitamins

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MILK PRODUCTS

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What Is Fermentation?Fermentation is a metabolic process in

which an organism converts a carbohydrate such as starch and sugar into alcohol and/or acid.

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Milk products

Cheese

Yogurt

Cultured buttermilk

Acidophilus milk

Kefir

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CHEESE

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CHEESECheese functions as the balance wheel of the

diary industry in developed countries.Made as a way of preserving the nutrients of milkCheese is the fresh or ripened product obtained

after coagulation and whey separation of milk, cream or partly skimmed milk, buttermilk or a mixture of these products.

Essentially the product of selective concentration of milk

Has formed the staple part of human diet for many centuries

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Cheese

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Milk • Fresh milk obtained from healthy

cows should be rapidly cooled and delivered to cheese factory.

• After milk arrives at the factory, it is commonly clarified with a centrifuge to remove small extraneous particles and somatic cells.

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Milk • Some cheese is made from raw milk,

but it is more common to use heat-treated or pasteurized milk.

• Head-treated milk is preferred because resultant cheese tends to be more flavorable than that made from pasteurized milk.

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Starter culture• One or several species of lactic acid bacteria

are commonly added to pre-warmed milk.• Small amount of acid produced by these

bacteria early in the cheesemaking process facilitates subsequent clotting of milk by the coagulant.

• Starter bacteria become a part of the finished cheese where they contribute to processes that occur in the cheese during ripening.

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Starter culture• Kind of cheese to be made determines

which organism to add to milk • Cheddar cheese- Streptococcus cremoris and /or

S.lactics, so called mesophilic lactic acid bacteria• Swiss cheese – Lactobacillus bulgaricus and S

thermophilus, so called thermophilic bacteria .• MO other than LAB sometimes added together

with them when cheese is made. Eg., Propionibacterium shermanii for swiss cheese or molds for camembert or blue cheese

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Lactococcus lactis Streptococcus cremorisBrevibacterium linens

Penicillium roqueforti Lactobacillus casei Lactobacillus plantarum

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Coagulant • A suitable coagulant is added to milk

usually for short term (eg., 30 min) after the starter culture was added.

• The coagulant is an enzyme which splits colloidal casein into a carbohydrate-rich peptide fraction and the insoluble paracasein that precipitates in the presence of calcium ions.

• Rennet extract obtained from the 4th stomach of young calves has been used as the coagulant.

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Coagulant • Replacements such as blends of

renin and pepsin, rennet extracts from mature cows and coagulants of fungal origin has been developed

• Mucor miehei, Mucor pusillus and Endothia parasitica

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Cutting the coagulum• Rectangular frames with thin wires,

horizontal on some and vertical on others, are used to cut the coagulated milk into cubes.

• Such cutting increases the surface area of the coagulum which facilitates its loss of whey.

• Cubes of coagulum also can be heated uniformly during the cooking process.

• Small cubes (eg., 1.3 cm³) lead to low moisture cheese, large cubes (4.5 cm³) lead to high moisture cheese

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Knive

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Cooking of the cut coagulum• After the coagulum is cut, the cubes of

coagulum (curds) suspended in whey are heated to a given temperature in a specific time.

• This heating is accompanied by stirring of the curd-whey mixture and causes the cubes of curd to contract and thus express the whey.

• Cooking also serves to control acid production by the lactic starter culture, to suppress growth of some spoilage bacteria, to influence texture of the curd, and to aid in control of the amount of moisture in the finished cheese.

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Draining whey• After cooking is completed, whey is removed

from the curd.• Done by draining whey from a vat that contains

the whey-curd mixture, using appropriate precautions to prevent loss of curd

• During the time needed for removal of curds from whey, some additional lactic acid is produced by the starter bacteria.

• Curd may be removed from vat and placed in a form or mold – camembert cheese

• Curd may remain in the vat so some knitting of curd particles can occur – cheddar cheese

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Whey

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Knitting of curds• Step allows further production of

lactic acid and for modification of the curd particles so they will adhere to each other and form single mass of cheese.

• Characteristic texture of a given variety of cheese is partially determined by this process

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Salting of curds• Salt is applied to curds in one or several ways.• Dry salt may be sprinkled on loose curds as in

manufacture of cheddar cheese or may be rubbed onto the surfaces of freshly made cheese.

• Freshly made cheese can be immersed in a nearly saturated aqueous solution of salt.

• Adding of salt contributes to the flavor, texture and appearance of cheese; controls production of lactic acid; suppress growth of spoilage MO; reduces the amount of moisture in finished cheese.

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Pressing of curds• This step sometimes comes before salting or

afterward.• Curds are placed into a form, sometimes called

hoop, and pressure is applied hydraulically or through use of weights.

• If cheese with an open texture is desired, external pressure may not be applied.

• Piling of curds in a vat, as in Cheddar cheese manufacture, is a form of pressing although hydraulic pressure is used later in manufacture of this variety of cheese.

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Pressing of curds• Pressing gives the cheese its

characteristic shape and contributes to its compactness.

• Free whey is expressed and knitting of curd particles is completed during pressing.

• Use of vacuum chambers during or after pressing can aid in removing occluded air from cheese and thus give the product a closely knit body.

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Ripening of cheese• Finished cheese is placed in a room with

controlled temperature and relative humidity and is held there for several months to several years , depending on the variety of cheese and the extent of ripening that is desired.

• Ripening allows for enzymatically-induced changes to occur in the protein and fat fractions of the cheese.

• These changes transform the freshly made cheese into one with desired and characteristic flavor, texture, aroma and appearance.

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Cheese making• https://www.youtube.com/watch?v=yCm___c

xaEA• https://www.youtube.com/watch?v=y9wLhRrj

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HARD PRESSED CHEESE

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Cheddar Cheese • Cheddar cheese is made in

cylindrical and block shapes.

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Manufacturing process1. Whole milk is clarified and pasteurized or heat

treated. Sometimes raw milk is used.2. Milk to be made into cheese is warmed to 31°C

and then inoculated with 0.5% of an active culture of S.cremoris and or S.lactics . Annatto cheese color also may be added if a cheese with a yellow-orange color is desired.

3. Inoculated milk is held at 31°C for 30 min to permit some bacterial activity, and then the coagulant is added. Coagulation of milk is completed in about 25 min.

4. The coagulum is cut into cubes of curd and the curd-whey mixture with continuous agitation is warmed to 38°C in 30 min.

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Manufacturing process5. Whey is drained from the curds which remain in

the vat, piled against the long sides of the vat, with a trench going down the center of the vat. The trenched curds are allowed to mat for about 15 min after drainage of whey is completed.

6. The trenched curd is cut into blocks which are triangular in shape and about 10 cm in thickness. These slabs of curd, after resting on one side for 15 min, are turned and again allowed to rest. This may be repeated after which they are piled 2 high and again turned every 15 min. The slabs can be piled 3 high for the last 30 min. This process is called “cheddaring” and allows for development of acid and textural characteristics in the curd.

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Manufacturing process7. The slabs of curd are fed into a curd mill which

is suspended over the vat. This device cuts the slabs of curd into smaller pieces of curd which are ready for salting.

8. Salt is applied and the curds are stirred for about 30 min. The salt is likely to be applied in 3 portions early during the stirring process.

9. Curd is placed into a metal form or hoop of the desired shape and size. The hoop is outfitted with an appropriate cloth which covers all interior surfaces of the hoop. Hoops filled with curd are placed on a horizontal hydraulic press and pressure is applied for approximately 18 hr.

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Manufacturing process10.Cheese is then covered with wax

and moved to storage for ripening. 11.Ripening can be for as short a time

as 3 months or as long as 1 year or more, depending on the intensity of flavor that is desired and the temperature at which ripening occurs.

12. Ripened cheese can be cut into consumer-sized portions, packaged and distributed.

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Cheddar cheese

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Swiss cheeseEg of type of cheese which undergoes

two fermentations – lactic and propionic acid fermentations

In which production of some gas is desirable because this causes formation of the characteristic holes or eyes in the body of the cheese

Made from raw milk

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Manufacturing process1. Fresh whole milk is clarified

mechanically and then standardized to contain 3% milkfat. Such standardization can be done by adding an appropriate amount of skim milk to whole milk; the procedure is needed so finished cheese will contain the right amount of milk fat which is 47-48% on a dry basis.

2. Milk is heated at about 68°- 70° C for 15-25 s. This serves to destroy unwanted MO that may be in the milk

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Manufacturing process3. Milk at abt 32° C is inoculated with

Lactobacillus bulgaricus, Streptococcus thermophilus , Propionibacterium shermanii. L.helveticus and L.casei have something been used instead of L.bulgaricus. Propionibacteria other than P.shermanii also have been tested with some success. Inoculated milk is held at 32° C to allow for some gwth by the added bacteria.

4. A suitable coagulum is added to milk at 32° C and milk is held at that temperature until a coagulum is formed.

5. The coagulated milk is cut with a wire knife so small cubes of curd are produced. This allows for expulsion of whey.

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Manufacturing process6. The curd, with the aid of an agitator, is

slowly moved about in the whey for abt 40 min. This further facilitates lose of whey and firms the curd.

7. The curd is “cooked” by slowly raising the temperature of the curd-whey mixture to 50° - 52° C over a 30-40 min period. After the desired temp has been reached, the curd-whey mixture is stirred for 30-70 min. This process aids the curd in losing the moisture and becoming firm, and control bacterial activity.

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Manufacturing process8. Curd and whey are pumped to a cheese-

molding vat. Air should not be introduced during the process. Whey is drained off from the curd.

9. Curd in the molding vat is covered appropriately and then weights are placed on the curd. This is called “pressing”, continues for 12-18 hr, and serves to expel gases and whey from the curd and to facilitate fusing of curd particles into a solid mass of cheese. Air, if present, interferes with this process.

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Manufacturing process10.The mass of curd is cut into blocks of

suitable size and the blocks are then placed into a solution containing atleast 23% NaCl. Additional salt may be sprinkled on the to of each block of curd as it floats in the brine. Cheese remains in the brine for 1-2 days. During this time a rind develops on the cheese, salt is absorbed by the cheese, and bacterial activity is retarded becoz the cheese cools.

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Manufacturing process11.Cheese is removed from the brine,

allowed to dry for a day or less, and then is wrapped with a flexible, extensible, fluid proof wrapping material. Wrapping material should be impermeable to O₂ and permeable to CO₂ so it can escape as it is produced during ripening of the cheese.

12.Wrapped cheese is placed in a cold room at 7° - 10°C for upto 10 days. This serves to stabilise the physical-chemical, enzymatic and microbiological system operative within the cheese at this time.

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Manufacturing process13.Cheese is then moved to the

warm room where it is held at 22° - 24°C for 2-7 weeks. During this time flavor and eyes develop.

14.Cheese is then refrigerated at 3° - 4°C until it is sold.

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Swiss cheese

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SURFACE RIPENED CHEESE

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Surface ripened cheesesSome cheese gain their principal

sensory characteristics through the combined efforts of bacteria and yeasts that develop on the surface of the cheese during ripening process.

Eg., brick and limburger cheese

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Brick cheese• Pasteurized whole milk at 32°C is

inoculated with S thermophilus. Alternatively, a combination of S thermophilus and S cremoris or L bulgaricus may be used.

• After brief incubation, rennet or another suitable coagulant is added into the milk; the resultant curd is cut into 0.64 cm or 0.95sm cubes and cooked at 38°C to 45°C.

• After the curd is sufficiently firm, enough whey is drained so that about 2.5cm remains above the curd surface.

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Brick cheese• Curd and whey are dipped or pumped into

rectangular hoops held on perforated screens.

• Oops of curd are allowed to drain for 6-18hr and are turned at intervals. Weights can be placed on the cheese during the draining process.

• Blocks of cheese are removed from hoops and immersed in brine containing 22% sodium chloride. Alternatively, salt can be applied to the exterior of the cheese.

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Brick cheese• After 24-36 hr in brine, the cheese is

removed and placed in a room at 15°C for 4-10 days. During this time the “smear” develops on the surface of the cheese.

• The smear is washed off, the cheese is waxed or packaged in plastic, and it is ripened for 4-8 weeks at about 4°C. More flavor can be obtained by leaving the smear intact for the entire ripening period.

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Brick cheese

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MOLD RIPENED CHEESE

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MOLD RIPENED CHEESE• Certain molds are used as the

major ripening agents of some cheese.

• Mold growth occurs throughout the cheese. E.g., blue cheese

• Growth of mold appears only on the surface of the cheese. E.g., camembert cheese

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Blue cheese• Cheese is ripened primarily by

growth and activity of mold throughout the cheese mass

• Was not made successfully in US until about 1918

• Abt 19 cm in diameter and weighs abt 2- 2.3 kg

• Round with a flat top and bottom

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Manufacturing process• Whole milk from cows is separated into

cream and skim milk fractions, and the skim milk is pasteurized.

• Cream is bleached by adding benzoyl peroxide, pasteurized and homogenized.

• Cream and skim milk are combined and 0.5% of an acctive lactic acid starter culture is added.

• Inoculated milk is held at 30°C for 1 hr to allow some acid production.

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Manufacturing process• A suitable coagulant is added, milk

is allowed to coagulate, and the resultant curd is cut into cubes with 1.6 cm wire knives.

• Curds are allowed to remain in whey for about 1 hr while additional acid develops. Curds and whey are then heated to 33°C, held briefly, and whey is drained from the curds.

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Blue cheese

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Camembert cheese• Eg of cheese that is made with a mold

developing only on the surface rather than throughout the mass of cheese as happens with blue cheese

• Typical camembert cheese- abt 11 cm in dia, 2.5-2.8 cm thick and weighs 225-250 kg.

• Interior is light yellow and waxy and creamy or almost fluid in consistency depending on the degree of ripening.

• Rind- thin felt-like layer of mold mycelium and dried cheese

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Camembert cheese• Mold is grey-white in color

sometimes bacterial growth occurs on the surface of the cheese

• Result in development of areas that are reddish-yellow in color

• Consumed within 6-7 weeks after it is made

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Manufacturing processes• Pasteurized whole milk with abt 3.5%

milkfat is adjusted to abt 32° c and is inoculated with 2% of an active lactic starter culture (S lactics/ S cremoris) plus a sporulated culture of P camemberti

• Annatto (yellow coloring) may be added to the milk

• Inoculated milk is allowed to ‘ripen’ for 15-30 min so that a titratable acid of 0.22% develops. Rennet extract is added to the milk is stirred and then held quiescently until a firm curd develops.

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Manufacturing processes• Curd is cut into cubes with 1.6cm knives.

Alternatively, uncut curd can be ladled into hoops.

• Curd is not cooked but is placed into open-ended, round, perforated, stainless steel molds or hoops. Filled hoops are allowed to drain for abt 3 hr at abt 22°C, no pressure is applied to the cheese during draining.

• Hoops of cheese are turned and draining continues. The turning process is repeated 3-4 times at 30min intervals.

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Manufacturing processes• Both flat sides of curd in hoops may now

be inoculated by spraying the surface with a fine mist of P camemberti spores suspended in water.

• After an hour, cheese is removed from hoops placed on a drain table, and held at 22°C for 5-6 hour. Weights are generally not placed on the cheese.

• Dry salt is applied to the surface of the cheese which is then held overnight at 22° c.

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Manufacturing processes• Cheese is held for 1-2 weeks at 10° to 15°

C and 95-98% relative humidity. It may be turned once during storage to facilitate uniform development of mold on the surface.

• Cheese is moved to storage at 4°C -10°C after being wraped in foil. Storage under these conditions may be for several weeks before the cheese is packaged and moved into distribution channels. Final ripening occurs during distribution.

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Camembert cheese

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YOGURT

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Plain yogurt• Plain yogurt normally contains no

added sugar or flavors inorder to offer the consumers the natural yogurt flavor for consumption as such or an option of flavoring with other food materials of the consumers choice.

• Used for cooking or for salad preparation wit fresh fruits or grated vegetables

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Plain yogurt

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Low fat milkCream

Skim milkNonfat dry milk

Pasteurize at 95°C for 30 min

Homogenize at 60°C 10.3k Pa (150 psi)

Mixing in hot vat 43°C

Package in containers

Incubate containers at 43°C to pH 4.5

Cool and store plain yogurt at 5°C upto 3-4 weeks

Standardize yogurt mixMilk fat 1-2%MSNF 10.5%

Stabilizer 0.7%

Pasteurize at 95°C for 30 min

Homogenize at 60°C 10.3k Pa (150 psi)

Culture vat, hold at pH 4.5 at 43°C

Package in containers

Cool and store plain yogurt at 5°C upto 3-4 weeks

Frozen culture or bulk starter

Cool at 43°C

Cool at 43°C

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Fruit flavored yogurt• Fruit incorporation is coviniently

effected by the use of a fruit feeder at 15-20% level.

• Incubation times and temperature are coordinated with the plant shedules.

• Incubation temperature lower than 40° C in general tend to impart a slimy or sticky appearance to yogurt.

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Fruit flavored yogurt

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Frozen yogurt• Manufactured in a cultured diary

plant and shipped to a soft serve operator or an ice cream plant.

• Mix may be prepared and frozen in an ice cream plant formulations :1.5-2.0% milk fat13-15% milk solids- not fat0.15-0.20% gelatin7-10% sucrose4-5% corn syrup solids

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Frozen yogurt• These ingredients are standardized in a

blend tank and pasteurized at 88°C for 40 min

• Mix homogenized at 58-63°C at 10.3 K Pa, cooled to 44°C.

• Yogurt culture is then inoculated and incubation of mix is continued until pH 3.9 is attained.

• The yogurt mix cooled to 25°C and remaining sugar as well as fruit is blended.

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Frozen yogurt• Special fruit preparations

designed for frozen yogurt are used at a level of 15-20%.

• Mix frozen in an ice cream freezer at 50-60% over run, packaged and hardened similar to ice cream.

• To obtain a soft serve product, a soft-serve freezer is used at a draw temperature of -8°C.

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Frozen yogurt

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Acidophilus milk• Produced by fermentation of milk with

Lactobacillus acidophilus• Possess therapeutic value particularly

following antibiotic therapy• Prescribed by dieticians and

physicians for digestive disorders• Fresh acidophilus milk contains in

excess of 500 million cells/mL, viable count decreases rapidly with storage.

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Lactobacillus acidophilus

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Kefir • Belongs to class of acid and alcoholic fermented

milk• Produced by fermentation with kefir grains• Grains are white to yellow in color and are

insoluble in water and common solvents. • When added to milk, their size expands by

imbibing water and their color changes to white.• Grains contain 24% slimy polysaccharide

secreted by the culture.• Symbiotic microflora contains yeasts,

lactobacilli, leuconostoc and lactic streptococci• Product is foamy and fizzy due to its CO₂ content• Kefir grains are generally recovered and used

repeatedly

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Kefir Kefir grains kefir

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BUTTER

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Butter • Serves as the balance wheel of the diary

industry• Surplus milk is converted into butter, while

during times of scarcity the milk intended for butter-making is used for more essential products.

• Butter may be defined as a fat concentrate which is obtained by churning cream, gathering the fat into a compact mass and then working it.

• Should be free from other animal fats, wax and mineral pils, vegetable oils and fats.

• No preservative except NaCl and no coloring matter except annatto or carotene may be added.

• Diacetyl may be added as a flavoring agent.

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Different types• Pasteurized cream butter : made from

pasteurized sweet cream. Milder in flavor than similar cream not pasteurized

• Ripened cream butter : cream in which a pleasant delicate aroma has been developed before churning by ripening.

• Unripened cream butter : made from unripened cream. Flavor is mild

• Salted butter : salt added• Unsalted butter : no salt• Sweet cream butter : acidity of churned

cream doesn’t exceed 0.2%

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Different types• Sour cream butter : more than 0.20%

acidity• Fresh cream butter : cold storage not• Cold storage butter : stored

temperature -18°C from sometime• Diary butter : made from a farm. Made

from unpasteurized sour cream not standardized for acidity

• Creamy butter : creamery or diary factory

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Manufacturing processes• Receiving milk/cream

o Unloadingo Gradingo Samplingo Weighingo Testing

• Pre-heating milk• Separation of milk : by centrifugal

methods• Neutralization of cream

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Manufacturing processes• Standardization of cream• Pasteurization / vacreation of cream• Cooling and aging of cream• Ripening of cream• Churning• Washing• Salting and working• Packaging and storage

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1. Receiving vats2. Centrifugal heaterj. Cream filter4. Separator5. separation tanks6. VA creator pasteurizer7. startdardizing vats8. Chiller9. Texturator10. Print formerli. ~frapping machine12. Packaging machine13. Bulk butter. packagingmachine with scale

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Milk Reception

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1.Milk reception 2.Preheating and pasteurization of

skim-milk 3.Fat separation

4.Cream pasteurization

5.Vacuum deaeration (when

used) 6.Culture

preparation (when used)

7.Cream ripening and souring (when

used) 8.Temperature

treatment 9.Churning/working

(batch) 10.Churning/workin

g (continuous) 11.Buttermilk

collection 12.Butter silo with

screw conveyor 13.Packaging

machines

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Milk Reception.Per-treatment

& Separation. Pre-heat Milk To 36-40°C.

Separate Into Skim Milk And CreamUsing An Electric Or Manual Cream Separator

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A Manu

al Crea

m Separator.

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Cream Standardization & Quality Control.Determination of butterfat content.

Determination of pH.

Determination of Acid Degree Value.

Organoleptic inspection for flavor defects.

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The Cream Should Be

Sweet (pH greater than 6.6). Free from off flavors

Not oxidized. Not rancid.

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Pasteurization

Heat the cream to at least 63°C for 30 minutes.

Or 72°C for 15 Seconds.

Ripening (Optional)Cultures are added to ferment milk

sugars into lactic acid and produce desirable flavor and aroma characteristic.

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Aging of Cream. control cooling design to give the fat the

required crystalline structure.

Ensuring proper churning and texture of the butter.

As a rule, aging takes 12 - 15 hours.

Pumped to the churn or continuous “buttermaker” via a plate heat exchanger.

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Churning of Cream. Eventually butter granules are formed, grow

larger, and merges.

Keeping the temperature as low as possible during churning.

In the end, there are two phases left:

1. Semisolid mass of butter.2. The spare liquid, which is called the buttermilk

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For continuous production

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A=7180mm.B=1700mm.C=3445mm.D=4000mm.

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For Batch Production

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Draining And

Washing Drain off the Buttermilk.

Add the same amount of chilled or cold water as the amount of buttermilk removed. (water should be drinking quality).

Churn at 10-15 rpm for 5 minutes. Drain the water and rotate the churn at 10-

15 rpm for 10-20 minutes

Washing process would ensure that all the butter milk is washed out of the butter. Otherwise the butter go rancid.

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Salting And

Working Acts as a preservative. Salt improve its flavor and shelf-life.

For salted butter, add salt (1-2% of butter weight) with continued slow churning.

Further, butter is worked to improve its consistency.

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Bulk Packaging Freezing

Storage ThawingConsumer Packaging

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Pack/Store Into greaseproof paper, aluminium foil, or plastic bags or tubs.

Approximately 5 -30 kg for bulk packaging. Usually 200 - 500 g for retail sale.

Butter should be stored away from highly aromaticfood products.

Frozen Store at -10 to -20°F (-23 to -29°C) for up to one year

Refrigerated Store at 32-38°F (0-3°C) for up to six months.

Relative humidity should be kept between (80-85) %.

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The capacity of the butter making machines(Continuous Butter Making

Machine) ranges from 500 kg to 14,000 kg butter/h.

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Butter

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CULTURED BUTTERMILK

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Cultured buttermilk• Obtained from pasteurized skim milk or

part skim milk cultured with lactic and aroma producing organisms

• S lactics or S cremoris, S lactics subsp. Diacetylactis and Leuconostoc cremoris are frequent cultures.

• Term buttermilk used for a phospholipid-rich fluid fration obtained as a by-product during churning of cream in butter manufacture.

• Viscous, cultured, fluid milk, containing a characteristic pleasing aroma and flavor

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Cultured buttermilk

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KOUMISS

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Koumiss • Similar to kefir except that mayer’s milk is

used• Russians- pulmonary TB treatment • Dose 1.4L per day for 2 months• Product alcoholic, slight intoxication• Alcoholic content 1-2.5%• Mare’s milk – low in casein content and

doesn’t curdle like cow’s milk• Grayish white wholesome drink• Starter – L bulgaricans and lactose

fermenting yeast Torulopsis holmii

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Koumiss • Lactic acid, ethanol and CO₂ - major

pdt; sour alcoholic flavor and fizzy appearance

• Slow fermentation- horse flesh or tendon or some vegetable matter added

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Cool to 28°C

Cool to 30°C

Cool to 20°C

Mayer’s milk

Inoculate with 30% starter

Ripening vessel : agitate, incubate at 28°C until desirable acidity (0.7-1.8% ) is attained

Bottle and cap

Incubate for 2 hr

Store at 5°C

Skim cow’s milk

Pasteurize at 70° C for 30 min

Inoculate 1 part with L bulgaricus and incubate at 37° C for 7 hr

Inoculate 2 parts with Torula sp. Incubate at 30°C for 15 hr

mix

Add 1 part mares’ milk and incubate at 28° C. Maintain acidity at 0.65 – 0.70% lactic acid by adding more mares’ milk. After abt 72 hr, stop adding mares’ milk and let acidity reach 1.4%

starter

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Koumiss

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ICECREAM

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Ice cream• Frozen diary product made by

suitable blending and processing of cream and other milk pdts, together with sugar and flavor with or without stabilizer or color and with the incorporation of air during the freezing process

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Selection of ingredients

Figuring the mix

Making the mix

Pasteurizing the mix (68° C/ 155° F for 30 min)

Homogenizing the mix (I stage 2500 psi) (II stage 500 psi)

(II

Cooling and ageing the mix (0-4° C / 32-40° F)

Freezing the mix (-4 to -5° C / 23- 25° F )

Packaging of ice cream

Hardening and storage of ice cream (-23 to -29° C / -10 to -20 ° F)

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Ice cream

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INDIAN DIARY PRODUCTS

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Kheer

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Khoa

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Rabri

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Kulfi

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Dahi

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Srikhand

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Paneer

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Chhana

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Makkan

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Ghee

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Lassi

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PRESERVATION

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