The Production of Natural Cheese

1. The Production of Natural Cheese Divya Reddy 9/21/05

2. Agenda • Introduction • Milk • History of Cheese making • Fundamentals of Cheese making • Milk Processing • Cultures • - Cheese making • - Cheese Ripening • - Cheese Conversion • Types of Cheese • Standards of Identity • Out of Standard Cheeses • References

3. Milk Milk is the whole, fresh, clean lacteal secretion obtained by the complete milking of one or more healthy cows. • Typical Milk Composition: • In Addition Milk contains: • Antibiotics • Enzymes (plasmins) • Micronutrients • Microorganisms Component Water Lactose Fat Casein Whey Protein Salts Total Composition 87.0% 5.1% 4.0% 2.5% 0.7% 0.7% 100% Function in Cheese Making microorganism growth; body & flavor source of sugar for starter cultures yield; affects color, body, and flavor yield; forms basic curd structure no function in native state required for coagulation of milk

4. Milk Milk • Milk composition may vary depending on.... - Breed of Cow/Genetics within Breed - Stage of Lactation - Age of Cow - Health of Cow - Nutrition - Milking Procedure - Season • During the summer months, fat and protein content in milk are the lowest. This reduces cheese yield.

5. History of Cheese Making Cheese and fermented milk foods are among natures most important contributions to civilization (Cheese and Fermented Milk Foods). The origins of cheese making date back centuries. According to folklore cheese was discovered when raw goat milk carried in a leather pouch across the desert, under the hot Arabian sun resulted in the curd and whey separating. Besides inspiring poems for children, cheese has been used as a form of currency in some parts of the world. Historically, these foods have helped populations survive famine. Nutritionally, cheese and fermented foods are an excellent source of protein, fat, calcium and vitamins. Cheese can be made from readily available ingredients and is long lasting and usually safe. It can also be produced from a variety of milks like cow, goat, sheep, buffalo , deer and camel milk. Almost every country in the world has a form of native Cheese, resulting in hundreds of varieties of cheese being available world wide. Some examples are the Greek Feta, Swiss Emmenthal, Italian Parmesan, French Brie and English Cheddar

6. US annual per capita cheese consumption On average, we each consume about 30 lbs of Natural Cheese per year! Worldwide Cheese Consumption 1920: 420 MM pounds 1970: 2,200 MM pounds Today: 6,000 MM pounds Cream & Neufchatel 2.20 Swiss 1.16 Varietals 1.63 Other Italians (Ricotta, Parmesan, Romano) 2.34 Mozzarella 7.93 American (Cheddar, Colby, Monterey Jack) 11.56

7. Fundamentals of Cheese Making Cheese Making is really just the separation of milk components. Cheese is a concentrated form of milk consisting of protein, fat, salt, minor milk components, and moisture. • The division of milk components during cheese making: • Cheese yield can be estimated using the Van Slyke Formula: • Typical retention factors: Cheese Type Cheddar Swiss Mozzarella Fat Retention 0.93 0.92 0.88 Casein Retention 0.96 0.96 0.96 Retained Solids 1.06 1.13 1.11

8. Cheese Making Overview of Cheese Making Processes MILK Standardize Pasteurize 163oF / 16 Sec. Cultures, Enzymes, Color and CalSol  CHEESE VAT 15 - 60 Min; 88 - 94oF 25 - 60 Min; 88 - 94oF 1. Ripen 2. Set 3. Cut 4. Forework 5. Cook 6. Stir-out 7. Draw Rennet 102 - 126oF Curd pH 5.8 - 6.25 SWISS 8. Press (UCM) 9. Drain 10. Press 11. Brine 12. Pre-Cooler 13. Cure Room 14. Cooler 15. Cut 16. Package CHEDDAR MOZZARELLA 8. Stir or Milled 9. Salt 10. Hoop 11. Press 12. Cure 13. Cut 14. Package 8. Matting (Table) 9. Mill 10. Cook/Stretch 11. Mold 12. Brine 13. Package

9. Milk Processing Milk is a perfect growth medium for micro-organisms. • The temperature of milk must be reduced to <45oF within 2 hours of milking. • Milk is transported in 50,000 lb. trucks. • Upon arrival at the manufacturing location, milk is inspected for the following.... • Temperature: 33oF to 45oF • Color & Appearance: white to off-white liquid • Odor: fresh, sweet and clean; free from any off odors • Antibiotics: negative or not found • Extraneous Matter: free from visible extraneous • The raw milk is then unloaded into large vertical tanks, or silos. Typically, silos range in size from 250,000 to 500,000 lb. • Additional testing is required, but not necessarily before use.... • Standard Plate Count (SPC): number of bacteria found in a 1ml sample, must be less than 50,000 • Cryoscope: a freezing point test to determine whether the milk has been diluted with water • Somatic Cell: a large number (>500,000/ml of milk) indicates the cows are suffering from udder disease.

10. Milk Processing • Milk components can be Standardized.... • Cream: the liquid milk product high in fat separated from milk, contains no less than 18% milkfat. • Skim Milk: milk from which enough milkfat has been removed to reduce total milkfat to less than 0.5%. • Lowfat 2% Milk: milk from which enough milkfat has been removed to reduce total milkfat to 2%. • Other: • Condensed(Evap.)Milk: concentration process to reduce water and increase solids • UF Milk: concentration process to reduce water and lactose, and increase solids • Powders: exists in many forms including NFDM, MPC, WPC, etc. • Before use in cheese making, milk must be heat treated to reduce the bacterial load, eliminate pathogenic bacteria, and inactivate enzymes. Pasteurization is the heat treatment of milk that ensures the destruction of vegetative forms of microorganisms, without significantly affecting the physical and chemical properties of the milk.

11. Milk Processing • Pasteurization of milk can be achieved by one of the following time/temperature combinations (minimums): • Process • LTLT (low temperature, long time) • HTST (high temperature, short time) • HHST (higher heat, shorter time) • Milk treatment at very high time/temperatures can affect the taste and performance of milk • cooked or burnt flavor • changing the chemistry of proteins Temperature 145oF 161oF 191oF 194oF 201oF 205oF 212oF Time 30 min 15 sec 1.0 sec 0.5 sec 0.1 sec 0.05 sec 0.01 sec

12. Cultures Role of Cultures in Cheese Making.... • Starter Cultures: metabolize the lactose into lactic acid. • control the growth of non-starter bacteria and pathogens • contribute to protein breakdown and flavor production • Adjunct Cultures: not the primary acid producers. • added for their contributions to flavor and texture Selection of Cultures.... • Cultures are selected based on the texture and flavor characteristics they contribute to the finished product. Starter Cultures: • Lactococcus lactis subspecies lactis and/or cremoris: basic lactic acid producing bacteria used in Cheddar, Colby, and Monterey Jack cheeses. • Lactobacillus lactis, Lactobacillus helveticus: used in lower moisture cheeses because of the higher cook temperatures Adjunct Cultures: • Lactococcus diacetylactis: produces the butter flavor found in Havarti. • Propionibacteria: produce CO2 gas which forms the holes (or eyes) and the characteristic “nutty” flavor in Swiss. • Ropy Cultures: used in fat free Cheddar as a fat mimetic.

13. pH control maintains cultures in log phase Cultures Starter Culture Types.... • DVS (Direct Vat Set) Starters: bacteria are concentrated and frozen, and can be used for direct inoculation of the milk. Very small quantities are used for each vat. • Bulk Cultures: bacteria are grown to sufficient concentrations in a medium, which is then used to inoculate the milk. • pH Control Bulk Cultures: As bacteria multiply the acid produced can inhibit further growth of the organisms. The acid is continuously neutralized in pH control systems, allowing bacterial growth until all food/energy sources are depleted. • Typical bacteria growth curve:

14. Cultures Troubleshooting... • Starter performance in the vat can be inhibited by: • antibiotics in the milk • bacterial contamination (non-starter bacteria take over) • bacteriophage contamination (a virus that infects bacteria) • Typical bacteriophage life cycle: • To prevent problems with starter culture: • apply sufficient heat treatment to the milk to destroy unwanted organisms • follow all GMP’s • starter culture selection and rotation DNA is injected into the cell. The phage attaches to the surface of the host. The host cell produces new phage DNA and proteins. Cell bursts, and new phages are released. New phages are assembled.

15. Cheese Making Overview of Cheese Making Processes MILK Standardize Pasteurize 163oF / 16 Sec. Cultures, Enzymes, Color and CalSol  CHEESE VAT 15 - 60 Min; 88 - 94oF 25 - 60 Min; 88 - 94oF 1. Ripen 2. Set 3. Cut 4. Forework 5. Cook 6. Stir-out 7. Draw Rennet 102 - 126oF Curd pH 5.8 - 6.25 SWISS 8. Press (UCM) 9. Drain 10. Press 11. Brine 12. Pre-Cooler 13. Cure Room 14. Cooler 15. Cut 16. Package CHEDDAR MOZZARELLA 8. Stir or Milled 9. Salt 10. Hoop 11. Press 12. Cure 13. Cut 14. Package 8. Matting (Table) 9. Mill 10. Cook/Stretch 11. Mold 12. Brine 13. Package

16. Cheese Vats Many of the finished product characteristics are determined in the vat. Types of Cheese Vats.... • Open Vats: open to plant atmosphere, manual processes • Closed Vats: enclosed, can be fully automated, sizes range from 25,000 to 60,000 lb. “Double O” Vats Processes Occurring in the Vats.... • Fill: Pasteurized milk is added to the vat between 88oF and 94oF (optimum growth temperature for the starter culture). • Annatto color can be added for yellow cheeses. • Cultures:Starters are added to the vat • Ripen: Starter cultures are added and begin to convert the lactose into lactic acid. • Ripening time varies (15-60 min) depending on cultures used and cheese type. • Acid production is measured by the pH or titratable acidity (TA).

17. Cheese Making Fat Ca Ca H20 Set:Rennet enzymes are added to coagulate (solidify) the milk. • Typical set time is 30 minutes. • Calcium chloride may be added to improve firmness of the set. • Rennet enzyme mechanism: Rennet cleaves a protein fragment, destabilizing the micelle. Casein micelles are very stable. A 3-D network is formed, trapping fat, water, and bacteria (curd). Micelles begin to “bond” in the presence of free calcium. • The entire vat forms a firm but soft set gel or coagulum

18. Cheese Making • Cut:The coagulum is cut into approximately 3/8” cubes to aid in the expulsion of whey (syneresis). • The size of the cut will influence finished product moisture (smaller curd size = more moisture lost). • The quality of the cut will affect cheese yield. If the curd is too firm it will tear when cut, resulting in losses of fat, moisture, and protein. • Fore Work:The curd is allowed to heal. After the cut, the curd is very fragile. • Cook:The curd is heated slowly to reduce the metabolism of the bacteria and promote whey expulsion. • The curd/whey mixture is heated by adding steam to the vat jacket, adding hot water directly into the vat, or a combination of both. • Final cook temperature varies depending on the starters and type of cheese. • If the temperature is increased too fast, the curd will develop a “skin.” This will inhibit syneresis, and curds will shatter. • Typical cook time is 30 minutes.

19. Cheese Making Stir-Out:The curd is held at the final cook temperature to allow for continued whey removal and lactic acid production. The longer the curd is stirred out the lower the pH will drop resulting in the curd being drier. A tool that is used in the production of “HARD” cheeses. Draw:The curd and whey are separated. • The acidity of the curd at draw plays an important role in the finished product characteristics of the cheese. A consequence of excessive acid production is cheese with a weak or “short” body (brittle, crumbly). • The curd and whey can be separated by pumping the mixture onto a drain table or a continuous draining matting conveyor (DMC).

20. Cheese Making Overview of Cheese Making Processes MILK Standardize Pasteurize 163oF / 16 Sec. Cultures, Enzymes, Color and CalSol  CHEESE VAT 15 - 60 Min; 88 - 94oF 25 - 60 Min; 88 - 94oF 1. Ripen 2. Set 3. Cut 4. Forework 5. Cook 6. Stir-out 7. Draw Rennet 102 - 126oF Curd pH 5.8 - 6.25 SWISS 8. Press (UCM) 9. Drain 10. Press 11. Brine 12. Pre-Cooler 13. Cure Room 14. Cooler 15. Cut 16. Package CHEDDAR MOZZARELLA 8. Stir or Milled 9. Salt 10. Hoop 11. Press 12. Cure 13. Conversion 14. Package 8. Matting (Table) 9. Mill 10. Cook/Stretch 11. Mold 12. Brine 13. Package

21. Cheese Making • At draw the cheese curd is pumped from the Vat to the drain table or drain belt. • Stirred Curd: • Curd and whey are pumped onto a drain table, where the whey is allowed to drain. • The curd is constantly stirred, preventing it from knitting back together. • Usually a batch process. • Commonly used for mild and medium. • Milled Curd: • Curd and whey are pumped onto a continuous draining belt. • The curd is allowed to fuse back together, and the curd mat is stretched (“cheddared”). • Commonly used in the manufacture of aged Cheddar and Parmesan. • Wash: • The curd can be washed with water to... • control acid production by removing lactose • control finished product moisture (a cool water wash will help increase finished product moisture)

22. Curd Handling Final processing of the curd is dependent on the cheese type. Salting: • The salt content of cheese ranges from 0.5-2.8%, depending on variety. • Purpose • slow the growth of bacteria • additional whey removal • enhances flavor • preservation (salt in moisture phase of >4.0%) • Methods • dry salting • brining (salt is absorbed into the cheese as it is submerged in a salt solution) Hooping and Pressing: Shapes curd particles into a cohesive block commonly, into 40 lb. block, 640 lb. block, 500 lb. Barrel or 20# wheels. • Final whey removal. • Press Plates • Press Probes • Some cheese varieties are vacuumed to achieve a closed texture. Cheddar is vacuumed, while Colby is not. • Some varieties are dipped in wax or coated with other ingredients.

23. Cheese Ripening Aged varieties of Natural cheese are cured after production for flavor and texture development. • Cheese curing is manipulated with.... - Adjunct cultures - Enzymes - Time - Temperature • Typical Cure Times • Swiss Cheese Cure • After brining, cheese is held at 45oF for 7-25 days while the curd knits. • Temperature is increased to 70-76oF. The propionibacteria begin to grow, producing propionic acid and releasing CO2 to form the eyes. • Temperature is reduced back to 40oF for the remainder of cure. • Cheddar Cheese Cure - Approximate Cure Time for Cheddar Cheese is at least 60 days with a peak flavor development time between 9 – 12 months. • Parmesan Cure - Cure Time estimate of 10 – 24 months. Surface ripened cheeses-Application of microorganisms or ingredients to the surface of a small block or wheel of cheese to develop distinct flavors and textures. Examples- Blue cheese, Garganzola, Brie

24. Cheddar Cheese Make Procedure Add Annato Color 1. Starter Addition 2. CalSol Addition 3. Rennet Addition Cut

25. Cheddaring Healing/ Cooking/Hold Whey Draining Milling Hoop Cure Pressing Salting

26. Conversion Most cheese enters the conversion plants as “640’s” (which actually weigh 680#) Cutting: • Most cheese enters the conversion plants as 40# or large 640# blocks. • The large cheese blocks are cut down to cube or bar sized pieces using a series of automated wire cutters. Commonly used cutters are: slabbers, profilers, windmills, guillotines, and cubers. • Resulting products are chunks and bars of all sizes, cubes, slices, half moon, wedges etc. Shredding: • Barrels or large blocks of cheese are first trimmed to smaller blocks and large cubes. • The cubes are processed through dicers or shredders. This equipment can do a variety of cut sizes like the fine shreds or the matchstick shreds. • Anticake is applied to the shreds to prevent the shreds from knitting back together. • Condiments and spices can also be added to the shreds at this point.

27. Packaging The packaging materials must protect the cheese through shelf-life. • All packaging involves 3 basic functions: Form, Fill, & Seal. • Shreds are filled into packages using a series of programmable scales. Chunks are indexed single file into packaging equipment. • After filling, the packages are flushed with gas (carbon dioxide and/or nitrogen) to reduce the residual oxygen content to below 2%. • The packages are sealed on all sides using hot metal bars. • Quality tests run on packages include: • Weight checks • Metal detection • Leakers (tests package seal) • Zippers (tests if the package opens properly) • Packaging protects the product from.... • Contamination (microbial, chemical, physical) • Oxygen (yeast & mold growth) • Moisture loss • Light (oxidation) • Undesirable odors

28. Types of Cheese Over 800 different styles of cheese are produced throughout the world • Classification of Cheese can be based on: • Natural vs. Process Cheese • Process Cheese combines Natural cheese with other ingredients like emulsifying salts which are then heat treated resulting in a longer shelf life than Natural cheese. Process cheese has its own Standards of Identity. • Moisture: • Very High High Medium Low • 80-55% 55-45% 45-34% 34-13% • Cottage Mozzarella Edam Romano • Ricotta Camembert Brick Parmesan • Cream Brie Swiss Dry Ricotta • Impastata Pizza Cheddar • Neufchatel Blue Provalone • Cheese and Fermented Milk Foods • Examples: • Hard Cheeses: Parmesan, Grana, Emmenthal; Gruyere • Semi-Hard – Cheddar, Gouda, Havarti • Semi-Soft – Blue Cheese • Soft – Cottage, Cream • * Dairy Processing Handbook • Fat on a Dry Basis: • Full Fat - >45% • Low Fat –10-25% • Skim/Fat Free Cheese - <10% • * Dairy Processing Handbook

29. Cheese Standards What is cheese, legally? Everything relating to food needs a name and all these names are determined using the CFR • The Code of Federal Regulation (CFR) Book 21 contains the “Standard of Identity”(SOI) of many food related products and food labeling terminology. • Everything from Infant Formula to Fish products to Milk and Cream to Cheese to Bakery products to Canned Fruits to Frozen Vegetables have Standards of Identity stated in the CFR • It even has standards for what you can call things if they are Out of Standard! • Legal and Regulatory have copies of these and are in charge of interpreting and utilizing the regulations. • There is no specific definition of CHEESE in the CFR however there is a standard for almost every common natural and processed cheese. • Canadian Food Inspection Agency (CFIA) is the Canadian Regulatory board.

30. Cheddar The first American Cheddar was produced in 1851 in Oneida County in upstate NY. • Standard of Identity: • 39% maximum moisture • 50% minimum FDB (fat on a dry basis) • There are two basic processes for the manufacture of Cheddar.... Stirred Curd: • Curd and whey are pumped onto a drain table, where the whey is allowed to drain. • The curd is constantly stirred, preventing it from knitting back together. • Usually a batch process. • Commonly used for mild and medium. Milled Curd: • Curd and whey are pumped onto a continuous draining belt. • The curd is allowed to fuse back together, and the curd mat is stretched (“cheddared”). • Commonly used in the manufacture of aged Cheddar. • Cheddar cheese is dry-salted. • Cheddar cheese can be either white (east coast) or colored (mid-west), and is characterized by a close-knit texture.

31. Italian Varieties Records dating back to 1200 –1300 A.D.describe the characteristics of Parmesan as they are today • Parmesan (Parmigiano Reggiano) originated in the Parma region of Italy • The formula remained unchanged for 700 years during which the area was under the rule of 7 different countries • Italian Parmigiano Reggiano is produced from April 1 – November 11 each year • The traditional make uses unpasteurized milk from the areas of Parma, Bologna, Reggio, Mantua, and Modena • Current Standard of Identity: Moisture Max. 32% FDB (fat on a dry basis) Min. 32% • Parmesan is available as Fresh shreds or in the Dry Grated form.

32. H20 H20 Fat Fat H20 Fat Fat Fat H20 H20 Mozzarella Italian pasta filata cheeses are stretched or kneaded into a consistency that can be molded. • Standard of Identity: • moisture content between 52% and 60% • 45% minimum FDB • The most unique characteristic of pasta filata cheeses, such as Mozzarella, is the cooking and stretching. • The proper curd pH is essential for cooking and stretching: • pH > 5.3 Tough, No Stretch • pH 5.3-5.0 Stretch, Flexible • pH < 5.0 Brittle, No Stretch • The process of cooking and stretching aligns all the protein in the same direction, giving Mozzarella a “stringy” texture: Before After Note: Mozzarella is also a brined cheese.

33. Whey Perforated Form Swiss Swiss cheese or Emmenthal is native to Switzerland • Standard of Identity: • 41% maximum moisture • 43% minimum FDB • The curd is cooked fairly rapidly to a high temperature to remove moisture and to reduce the rate of acid production. • Two factors help give Swiss cheese the correct texture to permit the formation of eyes.... • High draw pH: cheese will have an elastic texture • Pressing under whey: cheese will have a closed, continuous texture • A Universal Cheese Maker (UCM) is used to press the curd under whey: • Swiss ferments overnight (~18 hrs) to achieve the target AM pH, and is salted by submersion in a brine.

34. Out of Standard Cheeses Filled Cheeses or Imitation Cheeses Protein Replacement - mainly with soy protein to make health claims or to produce a cheaper product Fat Replacement – with unsaturated fats such as Cannola oil, Sunflower oil, Corn oil etc. to make health claims or produce a cheaper product

35. Whey Processing What happens to theother 90%? Whey, the by-product of cheese making, has many uses. • Typically the fines and whey fat are separated from the remainder of the whey. • The remaining whey can be concentrated into a liquid or powder (WPC) for use in processed cheese, ice cream, starter media, breads, baby food and chocolate coatings. • Alternatively, the solids can be further separated.... • WPI (whey protein isolate): used in protein drinks/snacks. • Lactose: fermented into alcohol or dried and used in pharmaceutical products.

36. References 1. Cheese and Fermented Milk Foods Volume I and II: Frank Kosikowski and Vikram Mistry 2.Dairy Processing Handbook –Tetra Pak 3. Cheese – Chemistry, Physics and Microbiology Edited by P.F. Fox 4. Code of Federal Regulations – 21- Food and Drugs Published by the office of Federal Register 5. A Complete Illustrated Guide to the Cheeses of the World – Juliet Harbutt