Fermentation of cheese (1)

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1. Fermentation of Cheese Presented by: Roll No: 17901-17911 5 th semester Morning

2. Introduction Fermentation: is a metabolic process that consumes sugar in the absence of oxygen. The products are organic acids, gases, or alcohol . Fermentation in food processing  : is the process of converting  carbohydrates to alcohol  or organic acids using  microorganisms like yeasts  or  bacteria under  anaerobic  conditions.

3. Cheese “A food made from the pressed curds of milk, firm and elastic or soft and semi-liquid in texture .’’ “A food consisting of the coagulated, compressed, and usually ripened curd of milk separated from the whey.”

4. History   Fermentation:  7000–6600 BCE in Jiahu, China. lactic acid fermentation : 1857, Louis Pasteur cheese: 5,500 BC in  Europe,  Central Asia,   Middle East

5. Microbes Associated with cheese fermentation Bacillus   licheniformis ,  Bacillus  sphaericus ,   Bacillus subtilis ,  Bacillus  pumilus ,  Bacillus  firmus , Escherichia coli Klebsiella Starter Cultures Lactococcus lactis Lactobacillus delbrueckii subsp. bulgaricus Lactobacillus helveticus Streptococcus salivarius subsp. thermophilus

6. Yeasts and Molds: Torula yeast ( Cyberlindnera jadinii ) Penicillium camemberti Penicillium roqueforti Penicillium glaucum

7. General cheese processing steps

8. Collection of milk Standardized milk Raw milk (as such ) sick cow milk (antibiotic treatment) Pasteurized

9. pasteurization High temp short time 72 o C for 15 sec Low temp long time 63 o C for 30 min Hydrogen peroxide treatment

10. Cooling of milk After pasteurization, cooled at 32 o C/ 90 o F. Raw milk is heated at 90 o F /32 o C. Favorable temperature for bacterial growth.

11. culturing Add starter culture. Ripen it at 32 o C for 30 min. Thus fermentation starts. pH lowers.

12. Starter culture is small amount of bacteria ,added in milk to start ripening by lowering the pH. Torula yeast brick , limberger cheese. Penicillium roqueforti blue cheese

13. coagulation Lactic acid produced. Addition of rennet. Rennet contain enzyme chymosin which convert k- casien into para -k- casien and glycomacropeptide . Leave it for 30 min for firm coagulation.

14. draining When cheese curd is ready, remove cheese whey. Presence of water and bacteria cause decomposition of food. So perform partial dehydration.

15. Scalding Temp is raised to 44 o C. T he curd is cut into small cubes to 'scald ' the curd particles.   Cheese whey is expressed from the particles. 

16. cheddaring The curds are allowed to set until they reach a pH of about 6.4 Loaves" of curds are cut.  After ten minutes, the loaves are turned over and stacking begins Every ten minutes when the loaves must be turned over, they are stacked. This step uses the weight of the loaves upon each other to help expel additional moisture. The first time this occurs, two loaves are stacked together. The next time, the loaves are turned, and two stacks of two are put together.

17. Addition of salt or brine Milled curd pieces are put back to vat 0.65% salt is added. Sprinkle dry salt on curds and mixing in salt. In some cheese varieties like mozzarella, curd is cut into loaves, which are then placed in brine(salt solutions).

18. Form cheese into blocks The salted curd pieces are placed in cheese hoops and pressed into blocks to form the cheese

19. Storage and aging (maturation) The pressed blocks of cheese are either bound with muslin-like cloth, or waxed or vacuum packed in  plastic bags to be stored for maturation Depending on the variety, cheese can be aged from several months to several years.

20. packaging Store it in vacuum packed or airtight plastic bag.

21. Types of Cheeses Several types on the basis of: Length of aging (cheese maturation) Texture Making method Fat content Milk source

22. Soft Cheese : Soft, smooth, creamy texture No heating and pressing 50-80% moisture content Uses: As a spread on bread and crackers Usually not for cooking

23. Examples Unripened/Fresh Not ripened or aged during processing Short shelf life Cottage, Ricotta, Mozzarella, Cream Ripened Camembert, Brie, Caciotta Salt cured or pickled Feta, Domiati

24. 2. Semi-soft Cheese More firm and compact 39-50% moisture content Can be used for cooking purposes Examples Ripened by mold growth Also known as blue or veined cheese Network of green blue veins of molds Molds include Penicillium roqueforti and P enicillium glaucum Strong and salty flavor Roquefort, Stilton, Gorgonzola, Danish blue Ripened by bacteria Limbruger , Brick

25. 3. Firm/Semi-Hard Cheese : Considered as “all purpose” cheese Pressed to remove most whey during production 34-45% moisture content Can be used for sandwiches and snacks Cheddar, Colby , Edam 4. Hard Cheese: < 39% moisture content Long maturation period Very long shelf life Can last for 2 years in refrigerator Examples Without Eyes, ripened by bacteria Cheddar, Caciocavallo With eyes, ripened by bacteria Emmental , Gruyere, Swiss

26. 5. Very Hard Cheese: 13-34% moisture content Very long aging period Can be upto 2 years Examples Asiago old, Parmesan, Romano, Grana 6. Processed Cheese: Made by melting a blend of grated cheese, milk, more salt, food coloring, flavors and seasonings Can be used for cooking Long shelf life Examples Processed cheese slices, Cheese spreads

27. Advantages of Cheese Many advantages as follow Nutritional Value: Contains vitamins such as A, B6, C, D, E, K Other vitamins include Thiamin, Riboflavin, Niacin. Dental Care: High Calcium Low lactose Raise pH of plaque offers protection against dental cavities.

28. Bone Health: Enriched in vitamin B, A, D Also contains calcium, magnesium, zinc Strengthen bones and cartilage Healthy for children and women (particularly lactating women) Controlling Hypertension: low fat cheeses such as Cottage, Feta, Ricotta are good for hypertension patients

29. Reduced Risk of Osteoporosis: In post menopausal women As cheese is enriched in vitamins, calcium and protein Omega 3 fatty acids: Found in cheeses made from cow milk Healthy for cardiovascular system and brain Enhance blood formation Strengthens liver Facilitate absorptions of nutrients

30. Disadvantages of cheese Cardiovascular problems: Cheese contains large amount of saturated fat High intake of saturated fats increase Cholesterol Results in increase risk of cardiovascular diseases, obesity, diabetes Allergies, intolerances, sensitivities: Persons sensitive to casein protein develops allergies Fresh cheeses like mozzarella triggers reaction in persons with lactose intolerance

31. Kidney Disorders: Phosphorus in high quantities Harmful for persons having kidney diseases Prostate cancer: High calcium causes prostate cancer Neonatal infection and death: Cheese promotes growth of Listeria bacteria L.monocytogenes cause serious infections in infants and pregnant woman