Processing Dairy Products

Transcription

1 Processing Dairy Products Unit: Animal Science and the Industry Problem Area: Livestock, Large Animal, Poultry, and Bee Industries Student Learning Objectives. Instruction in this lesson should result in students achieving the following objectives: 1 Describe the steps in processing milk; identify the types of milk; and explain how milk is graded and classified. 2 Describe samples of milk for flavor and odor, and critique milker head units for defects. 3 Describe the steps of the cheese-making process, and identify the four groups of cheese. 4 Identify samples of cheese. 5 Describe the steps of the yogurt-, sour-cream-, and cottage-cheese-making processes. 6 Describe the steps of the butter-making process and the butter types. 7 Describe the marketing options for dairy products. 8 Distinguish between real and artificial dairy foods. List of Resources. The following resources may be useful in teaching this lesson: Corresponding E-unit(s). Danville, IL: CAERT, Inc. List of Equipment, Tools, Supplies, and Facilities Copies of sample test Visuals from accompanying masters Copies of student lab sheet Page 1

2 Terms. The following terms are presented in this lesson (shown in bold italics): cattle byproducts cheddaring curd curdling homogenization pasteurization solids-not-fat (SNF) standard plate count (SPC) standardized whey Interest Approach. Use an interest approach that will prepare the students for the lesson. Teachers often develop approaches for their unique class and student situations. A possible approach is included here. Display a number of dairy food products. As a class, discuss what makes these products similar and different. Ask the students how they can tell if the products are true dairy products. What are the steps required to transform milk into solid products? Have students taste test milk products and discuss the different flavors. Discuss the nutritive value and wholesomeness of milk. Take time to discuss lactose intolerance and the need for substitute products. SUMMARY OF CONTENT AND TEACHING STRATEGIES Objective 1: Describe the steps in processing milk; identify the types of milk; and explain how milk is graded and classified. Anticipated Problem: What are the steps involved in processing milk? What are the types of milk? How do you grade and classify milk? I. Milk processing involves many steps. All farm equipment must be kept and maintained to government and industry standards to ensure safe, healthy, and quality products. After dairy cows are milked, the liquid is cooled from the cow s body temperature to below 40 F (4 C). It is refrigerated until the milk tanker driver arrives to record the amount of milk, make special notes of the milk temperature and odors, and transport the product. (If milk does not meet temperature regulations or has an off-odor, the driver refuses the milk.) Page 2

3 A. At the milk processing plant, samples are checked for proper temperature, total acidity, flavor, odor, cleanliness, and the absence of antibiotics. The butterfat and solids-not-fat are also analyzed. Solids-not-fat (SNF) contain the protein, lactose, and minerals and are the total solid minus the milk fat. The amounts of butterfat and SNF can vary because of cow breed, feed supply, and the time of year. Many producers depend on these counts for contract payments. B. Within 72 hours, the milk must be processed. The milk is pasteurized at the processing plant. 1. Pasteurization is the process of heating the milk to destroy all pathogenic bacteria. Milk can be pasteurized by heating it to 161 F (72 C) for 15 seconds. Then the milk is immediately cooled below 40 F (4 C). 2. Ultrapasteurization is used to extend the shelf life of refrigerated products and to enable products to be kept at room temperature. C. Milk is then standardized. Milk is processed through centrifugal separators to create a skim portion and a cream portion. Most milk in the United States is standardized. The cream portion is added back to the skim portion based on the desired fat content for the product. Water is never added to lower the butterfat. The extra cream from this step is used to make ice cream or butter. 1. Common products/types of fluid milk a. Whole milk (3.25 percent fat) b. Low-fat milk (0.5 percent, 1 percent, 1.5 percent, or 2 percent fat) c. Skim milk (less than 0.5 percent fat) d. Flavored milk 2. Major types of milk a. Fluid milk b. Manufactured milk products (evaporated milk and sweetened condensed milk) c. Powdered milk d. Specialty milk (multi-vitamin, lactose-treated, or low-sodium) D. Homogenization is the process used to prevent the cream from rising to the top of a finished milk package. Homogenization reduces the milk fat globule size, allowing for even distribution in milk. This process does not affect the nutrition or quality of the product; it keeps the final product from forming a cream topping. E. Vitamin quantities are often reduced as a result of the heating process and the removal of butterfat, so milk is commonly fortified with vitamins A and D. The milk label indicates if the milk has been fortified. 1. Vitamin A is a fat-soluble vitamin. a. Whole milk is known as a good source of vitamin A because of the higher fat content. b. There are lower quantities of vitamin A in 2 percent, 1 percent, and skim milk. Page 3

4 c. Specific requirements require the fortification of vitamin A in lower fat milks. 2. Vitamin D is also a fat-soluble vitamin that occurs naturally in milk at low levels. a. The process of vitamin D fortification started in the 1930s to reduce the occurrence of rickets in children. b. Today, vitamin D is necessary for human health. It helps with calcium absorption and bone health in addition to providing cancer-fighting properties. F. Quality control is conducted through all of the steps in milk processing. Numerous tests and samples are gathered to analyze the presence of microbiological organisms. 1. A standard plate count (SPC) is performed to determine the total number of bacteria for a specific amount of milk. This test is used in the grading procedure. 2. Milk can be Grade A or Grade B. (Grades are not the same as classes of milk.) a. Grade A milk meets the sanitary standards for fluid milk products and can be used for any dairy product. b. Grade B milk is considered a manufacturing grade. This grade meets slightly lower standards and can only be used for manufactured dairy products. G. Classification is used for pricing systems. Producers may participate in the Market Order Program, which establishes prices according to milk uses. 1. Class I milk is the highest price class and is used for fluid milk products. 2. Class II is used for soft milk products like yogurt, cottage cheese, and ice cream. 3. Class III is used for hard cheeses. 4. Class IV is used for butter and for milk products in dried form. H. Milk products will contain a sell-by date on the finished product package. This refers to the last date on which the product can be offered for sale. Most dairy-processing companies will guarantee the freshness and quality of the product for at least one week past the date printed on the package. I. When the product has completed all of the steps in processing, pasteurization, standardization, homogenization, and quality control, it is packaged into gallon, half-gallon, quart, pint, and half-pint containers. These containers are kept below 40 F (4 C) in storage warehouses where they are stored for a short period of time and then shipped to supermarkets. The refrigerated trailers unload quickly, and milk is immediately placed into cold storage and is ready for purchase. Students should read the corresponding E-unit(s). Use VM A to summarize the steps in processing milk. Discuss the importance of proper temperature, total acidity, flavor, odor, cleanliness, and the absence of antibiotics. Lead into a discussion of quality and the wholesomeness of the final product. Discuss how Page 4

5 and why safeguards are higher in the dairy industry. List how quality control is used in every step of milk production (feeding, sanitizing machines, transporting, and processing). Objective 2: Describe samples of milk for flavor and odor, and critique milker head units for defects. Anticipated Problem: How do you evaluate milk samples for flavor and odors? How do you critique milker head units for defects? II. The flavor, scent, and visual inspection of milk are important to the overall quality and can be affected by the cow s health, consumed feed, bacteria, chemical changes, or absorption of foreign flavors after processing. The process of judging and scoring milk and other milk products is consistent throughout processing. Milk is checked for irregularities at various points, including storage. Dirty equipment can impact the results, so sanitation is critical. These quality control practices ensure safe, healthy, and delicious milk products. A. Determining problems 1. An off-flavor can be found by smelling the open container rather than a small sample. The container houses a greater volume of the irregularity, making it easier to detect odors. 2. The next step involves tasting the milk. Samples should be at room temperature. The colder the sample, the harder it is to distinguish certain flavors. The major flavor defects are bitter, feed, flat-watery, foreign, garlic/onion, high acid, malty, oxidized, rancid, salty, and unclean. It is important to study the origin of these defects to gain a better understanding of the imperfections. B. The cleanliness of milking machine parts can influence the milk flavor. As a result, the condition, maintenance, and sanitation of milking machine parts are critical to dairy operations. These parts can cause high-quality milk to be downgraded due to poor attention to the overall condition. These are the possible defects of rubber parts: 1. Dirty or milk stone These parts have evidence of gray and/or chalky soil or light films of soil. They may also be sticky and have a greasy appearance. 2. Checked or blistered These parts have been used too long and have been poorly cleaned. 3. Leaky parts These parts will allow air into the system due to holes in air hoses. 4. Poorly fitted parts These parts are obviously not designed to fit and may include split hoses or broken hoses that are too short. C. These are the possible defects of metal parts: 1. Dirty or milk stone These parts show evidence of soil or chalky material. 2. Badly dented or damaged These parts have damage that is sufficient enough to interfere with the function of the parts and with cleaning/sanitizing them. Page 5

6 3. Pitted or corroded These parts have evidence of rust and darkened surfaces. 4. Open seams These parts have evidence of broken joints, heads, or screws. Students should read the corresponding E-unit(s). Use VM B. Provide samples of milk for students to practice detecting problems with flavor. Then provide pictures of milker units so students can observe flaws and determine possible reasons for any off-flavors. Objective 3: Describe the steps of the cheese-making process, and identify the four groups of cheese. Anticipated Problem: What are the steps in the cheese-making process? What are the four groups of cheese? III. The varieties of cheese are based on ingredients, processing steps, and characteristics of the finished product. A. Cheese can be made from a combination of fluid milks. Cottage cheese is made from skim milk; Swiss cheese is made from a mixture of whole and skim milk; and cheddar cheese is made from whole milk. Heat-treated or pasteurized milk is commonly used in cheese production. B. Cheese is made by removing most of the milk solids from the milk through a process called coagulation or curdling. Curdling is the process that causes the milk to form into curd the part of milk that coagulates when milk turns sour or is treated with enzymes. 1. First the milk is heated. Then a liquid starter culture is added. The bacteria from the culture will form acids in the milk, causing the milk to sour. The starter culture and milk may be held for a period of time to allow for ripening. 2. Rennet is added to force the milk to thicken. It contains the enzyme rennin and is found in the stomachs of young calves. Other enzymes may be used in the process. After the mixture is stirred, the curd forms. The curd is separated from the whey (the watery liquid part of the milk mixture in the cheese-making process) by heating and draining it. C. The next step may involve texture of the curd. This step is also called cheddaring; it helps to force out more whey and allows for fermentation to continue until a desired ph level is reached. D. Dry salt or brine is used next to achieve a desired flavor. For example, the curd of mozzarella is formed into laves and placed into a brine, salt-water solution. E. Cheese is formed into blocks. F. The ripening or curing of cheese is exposed to a temperature/humidity controlled environment for a specified duration. Different types of cheese require months or years to age. The changes that occur during the curing/aging process depend on the enzymes, bacteria, mold, yeast, or combination of these agents. Page 6

7 G. After the cheese has met the desired age, it may be cut, packaged, waxed (if necessary), and put into blocks. H. Cheese can be grouped as very hard, hard, semi-soft, or soft. The type of cheese depends on the kind of milk used, the methods used in the coagulating of milk, the cooking and forming of the curd, the type of culture used, the salting method, and the ripening conditions. A soft cheese, like cottage cheese, is an unripened cheese with 80 percent moisture. Parmesan and Romano are very hard cheeses (grated or shaker cheeses). These ripened cheeses have approximately 33 percent moisture. Use VM C to summarize the steps in making cheese. Discuss how every type of cheese has specific processing steps and requirements. Compare and contrast the four groups of cheese. Use the following Web site to show students short videos of the cheese-making process: cms#. You may also use videos from YouTube ( and discuss the differences in cheese-making processes in other countries. Objective 4: Identify samples of cheese. Anticipated Problem: How do you identify samples of cheese? IV. Cheese identification should be based on body, texture, color, and flavor. A. Body refers to the physical properties. Observing and feeling the firmness, cohesiveness, elasticity, and plasticity will help to determine and describe the appearance. The physical properties are affected by the methods used during processing. B. Texture refers to how the cheese particles are bound together. Open textures show spaces between the particles; in contrast, closed textures show very few openings. C. Color can range from a cream or off-white to a light or heavy yellow. The color should only act as a guide when identifying cheese. D. Flavor is the final factor. The use of taste and smell help to distinguish the cheese types. Cheeses have specific scents. Noting the odors and tasting small pieces will assist in identification. Use VM D to review the common cheese types and their characteristics. Bring in several plates of cheese (four to six types). Have students establish a routine in tasting (e.g., work a portion between the thumb and forefinger, smell for odors, and taste a small piece). Have the students rank the cheeses based on their critiques and have them identify the samples. Page 7

8 Objective 5: Describe the steps of the yogurt-, sour-cream-, and cottage-cheese-making processes. Anticipated Problem: What are the steps of the yogurt-, sour-cream-, and cottage-cheese-making processes? V. Yogurt, sour cream, and cottage cheese products are handled under controlled conditions. These products require the addition of bacteria cultures to fluid milk for fermentation to occur. These bacteria cultures will convert lactose into lactic acid. The fermentation process and the specific bacterial culture used will determine the end product. A. Yogurt products may use whole milk, low-fat milk, or skim milk, depending on the type of product desired. Yogurt must contain at least 3.25 percent milk fat. Low-fat yogurt allows up to 2 percent milk fat, and nonfat yogurt allows less than 0.5 percent milk fat. Other dairy products, such as cream, are used to adjust the fat content. Nonfat dry milk is used to adjust the solid content. Stabilizers (e.g., alginates, gelatins, and starch) are used to improve the body and texture by increasing firmness and preventing whey separation; they also help to keep the fruit in yogurt uniformly mixed. Flavors, sweeteners, and fruit may be added to yogurt for variety. Bacterial cultures are used to ferment lactose so lactic acid results, producing the characteristic yogurt flavor. The general steps in the yogurt-making process are listed below. 1. The milk composition should be adjusted and the ingredients blended. This allows for the proper percentage of milk fat. 2. The milk mixture should be pasteurized. A heat treatment of 185 F (85 C) for 30 minutes is used to denature the whey, allowing the proteins to form a more stable gel. 3. Homogenizing the milk ensures that all of the ingredients are thoroughly mixed. 4. The product is cooled at 108 F (42 C) the ideal growth temperature for a starter culture. 5. The product should be inoculated with a starter culture (main starter cultures used in yogurt production are Lactobacillus bulgaricus and Steptococcus thermophilus) and mixed into the cooled milk. 6. The product is then held at 108 F (42 C) until a ph of 4.5 is reached. This allows for the soft gel to form. 7. The yogurt is cooled to 44 F (7 C) to stop the fermentation process. 8. Fruit and flavors are added. Two types of yogurt are produced. In set style yogurt, the fruit is added in the bottom of the cup. In Swiss style yogurt, the fruit is blended. 9. The finished product is ready for packaging. B. Sour cream can be offered as regular, reduced-fat, or nonfat. Regular sour cream contains at least 18 percent milk fat and is made from light cream. Reduced-fat sour cream contains at least 25 percent less milk fat than regular sour cream and Page 8

9 is made from half-and-half. Nonfat sour cream contains no more than 0.5 grams of milk fat per serving. Sour cream may be cultured or acidified light cream. Cultured sour cream is soured and thickened by adding lactic acid bacteria to pasteurized cream. The lactic acid coagulates the protein and thickens the cream. This results in the characteristically sour flavor of the final product. Acidified sour cream is soured and thickened with the addition of an acid-like vinegar and does not go through the fermentation process. Steps to culture sour cream are as follows: 1. First, the culture (Streptococcus lactis) is added to pasteurized light cream. 2. Then it is incubated at 72 F (22 C) until the desired flavor and the desired thickness are reached. 3. Additional nonfat milk solids and stabilizers are added, as needed. C. Cottage cheese is considered a fresh, unripened, soft cheese with a mild and slightly acidic flavor. Four types of cottage cheese exist: creamed cottage cheese, low-fat cottage cheese, nonfat cottage cheese, and baker s cheese. The creamed cottage cheese is made with nonfat cottage cheese and a light cream dressing. It contains at least 4 percent milk fat. Low-fat cottage cheese is made with nonfat cottage cheese and a light cream dressing with 0.5 percent, 1.5 percent, or 2 percent milk fat. Nonfat cottage cheese is made from nonfat milk and contains no more than 0.5 grams of milk fat per serving. Baker s cheese is a form of cottage cheese in which the liquid has been pressed or drained. It is firm enough to crumble and is used in cooking/baking. The following are steps in the creation of nonfat cottage cheese: 1. A bacterial culture or food-grade acid (vinegar) is added to pasteurized milk. This causes the separation of the milk solids from the whey. 2. The curds are formed and gently cut into pieces that allow the whey to be drained. 3. The curds are cooked and pressed to force out more whey. 4. The curds are rinsed, and salt is added. 5. Light cream dressing is added to achieve the desired finished product. Use VM E. Have students complete LS A. Discuss the importance of fermented dairy products. Indicate the differences between cultured and acidified. Discuss the characteristic taste of these products. Page 9

10 Objective 6: Describe the steps of the butter-making process and the butter types. Anticipated Problem: What are the steps in the butter-making process? What are the types of butter? VI. Butter is made from pasteurized cream and comes in several types. A. Making butter involves several steps. 1. The cream is churned or shaken until the milk fat/butterfat is separated from the buttermilk. 2. After churning, the butter is rinsed and salted (if desired). 3. The excess buttermilk is removed. B. There are several types of butter products. 1. Traditional butter is made from a sweet cream (also known as pasteurized cream), has salt added for flavor, and acts as a preservative. Butter contains at least 80 percent milk fat, 18 percent water, and 2 percent solids. 2. Unsalted butter is also available. 3. Whipped butter is another product. During the churning, air is whipped into it to make the product fluffy and easy to spread. 4. Clarified butter is made from regular butter; however, the water is evaporated as it is heated slowly. The milk solids are separated from the fat. It is mainly used in frying or sautéing because it can be heated at higher temperatures. It will not burn or smoke like regular butter. 5. Cultured butter is produced from a churned cream that has been soured by a lactic acid culture. Ask students what type(s) of butter they use. Use VM F. Discuss how butter used to be made versus the modern conveniences of equipment. Compare and contrast butter and margarine. Objective 7: Describe the marketing options for dairy products. Anticipated Problem: What are the marketing options for dairy products? VII. Even though the dairy industry is probably best known for milk production, several additional items are used to generate dairy farm income. A. Milk production is important to the economy because milk is used in many products. In terms of nutrition, milk is one of the least expensive products. Because the average American uses just under 600 pounds of milk and other milk products each year, the industry must produce more than 150 million pounds annually to meet consumer demands. Milk is produced by cows after the first calves are born. Cows continue to produce milk if they are milked frequently and Page 10

11 fed a nutritious ration for a long time. When milk production starts to drop, the cow must be bred again and have another calf so more milk can be produced. B. Veal is the meat of young calves that are not used for replacement animals in the dairy herd. Veal calves must be fed a specific diet of milk only to keep the color of the lean meat in the carcass light pink. Veal calves are usually under three months of age. C. Beef is the meat from cattle. When cows are no longer profitable because of age, production, or reproductive problems, they are shipped to harvesting facilities and used for beef. If the male offspring are not kept for breeding programs, the steers are used for beef. They are fed until harvesting weight is reached and then are used for meat and byproducts. D. Cattle byproducts are products made from various cattle parts. Cattle byproducts come from the carcass, fat, bones, glands, intestines, brain, heart, and more. Some byproducts are used to make cat and dog food. Other byproducts are used to make medicines, marshmallows, cosmetics, furniture, and clothing. Use VM G. Discuss the diversity of dairy operations and the importance of multi-purpose products. Also, discuss other marketing avenues, such as organic milk products or antibiotic-free products. Bring in some items that are made with cattle byproducts so students can see how frequently we utilize items with such ingredients. Objective 8: Distinguish between real and artificial dairy foods. Anticipated Problem: What is the difference between real and artificial dairy foods? VIII. Many foods are made as imitation or substitute products, and these products do not contain the same nutrients as the real products. The main three categories where imitations are likely to be found are dairy foods, juices, and processed meats. A. The main difference in imitation dairy products is the lack of real milk as the base product. Imitation dairy products can be found in: 1. Cheese Colby, cheddar, cream, mozzarella, and American pasteurized processed cheese 2. Butter 3. Cream 4. Whipped cream 5. Sour cream 6. Ice cream 7. Milk Page 11

12 B. Imitation or artificial foods do not provide the nutrients of the traditional products. The U.S. Food and Drug Administration defines the word imitation as nutritionally inferior. 1. These products are inconsistent because the ingredients can be changed whenever desired by the manufacturers. 2. These products lack milk as the base product. 3. When comparing the food labels of real versus artificial dairy food products, it is crucial to look for the REAL seal. This indicates the food was made with milk. Examples of real versus artificial are the following: half-and-half coffee cream versus nondairy creamer, whipped cream versus whipped toppings, cheese versus vegetable cheeses, and butter versus margarine. Bring in several real and imitation dairy products. Have students pair up and take turns being blindfolded while tasting the real and the imitation products. The partners should record the responses/descriptions. Use VM H to compare the differences between real and artificial dairy foods. Discuss the importance of the REAL seal in the dairy industry. Review/Summary. Use the student learning objectives to summarize the lesson. Have students explain the content associated with each objective. Student responses can be used to determine which objectives need to be reviewed or taught with a different approach. The anticipated problems in this lesson and Checking Your Knowledge in the corresponding E-unit(s) may also be used in the review/summary. Application. Use the included visual masters and lab sheet to apply the information presented in the lesson. Evaluation. Evaluation can involve observing student performance throughout the lesson. The sample written test can also be used. Answers to Sample Test: Part One: Matching 1. c 2. a 3. h 4. d 5. f 6. e 7. g 8. b Page 12

13 Part Two: Completion 1. Curdling 2. stabilizer 3. lactose and lactic percent 5. Clarified 6. REAL Part Three: Multiple Choice 1. c 2. b 3. a 4. d 5. c 6. b 7. a 8. d Page 13

14 Sample Test Name Processing Dairy Products Part One: Matching Instructions: Match the term with the correct definition. a. standardized e. cattle byproducts b. curd f. standard plate count (SPC) c. solids-not-fat (SNF) g. whey d. homogenization h. pasteurization 1. This contains the protein, lactose, and minerals 2. This process uses centrifugal separators to create a skim portion and a cream portion 3. This process involves heating milk to destroy all pathogenic bacteria 4. This process prevents the cream from rising to the top of a finished fluid milk package 5. This is performed to determine the total number of bacteria for a specific amount of milk 6. These are items made from various parts of cattle 7. This is the watery liquid part of the milk mixture in the cheese-making process 8. This is the part of the milk that coagulates when milk turns sour or is treated with enzymes Part Two: Completion Instructions: Provide the word or words to complete the following statements. 1. is the process to cause the milk to form into curd. 2. A(n) is used to improve the body and texture of a yogurt product. 3. Bacteria cultures will convert into acid. 4. Butter contains at least milk fat, 18 percent water, and 2 percent solids. 5. butter is made from regular butter; however, the water is evaporated as it is slowly heated. 6. The seal indicates that the food was made with milk. Page 14

15 Part Three: Multiple Choice Instructions: Circle the letter of the correct answer. 1. Milk is commonly fortified with vitamins. a. C and B b. B and K c. A and D d. A and K 2. Milk is graded for quality by using grades. a. AA and A b. A and B c. AA and BB d. A and BB 3. Milk classification is used for. a. pricing systems b. quality grading c. processing steps d. sell-by dates 4. Class III milk is used for. a. soft milk products b. fluid milk products c. butter d. hard cheeses 5. The possible defects of rubber parts on milker head units are. a. dirty or milk stone, checked or blistered, open seams, and leaky parts b. dirty or milk stone, corroded parts, open seams, and poorly fitted parts c. dirty or milk stone, checked or blistered, leaky parts, and poorly fitted parts d. dirty or milk stone, badly dented or damaged, pitted or corroded, and open seams 6. The process helps to force out more whey and allows for fermentation to continue until a desired ph level is reached. a. curdling b. cheddaring c. pasteurization d. homogenization Page 15

16 7. Cheese can be grouped as. a. soft, semi-soft, hard, and very hard b. soft, medium, hard, and solid c. soft, semi-soft, medium, and hard d. semi-soft, hard, very hard, and solid 8. Cheese should be identified based on. a. body and flavor b. texture and color c. taste d. All of the above Page 16

17 VM A STEPS IN PROCESSING MILK Dairy cows are milked. Then the milk is cooled from the body temperature of the cow to below 40 F (4 C). It is stored in refrigeration units at the farm until it is picked up by the driver of an insulated tanker truck. The milk tanker driver records the amount of milk and makes special notes of the temperature and odors. At the processing plant, samples are checked for proper temperature, total acidity, flavor, odor, cleanliness, and the absence of antibiotics. The butterfat and solids-not-fat are analyzed. The milk is pasteurized, standardized, and homogenized at the processing plant. Milk is fortified with vitamins A and D. Quality control is conducted through all the steps in milk processing. It is packaged into gallon, half-gallon, quart, pint, and half-pint containers. Containers are held below 40 F in cold storage warehouses. The product is shipped to supermarkets. Page 17

18 VM B FLAVOR AND MILK HEAD UNIT DEFECTS Flavor Defect Possible Causes Bitter Feed Flat-watery Foreign Garlic or onion High acid Malty Metallic/oxidized Cows eating bitter weeds Certain types of bacteria Strong feeds used before milking Poor ventilation Changes in feed Diluted with water Cleaners in equipment Barn or crop sprays Cow eats or smells wild garlic or onion Equipment unclean Poor cooling of milk Bacteria Poor cooling of milk Light exposure of milk Exposed copper in milk equipment Page 18

19 Flavor Defect Rancid Salty Unclean Possible Causes Air leaks in systems Late lactation Cooler deficiency Late lactation Mastitic milk Unclean equipment Moldy feed Milk-stoned equipment Rubber Part Defects Dirty or milk stone Checkered or blistered Leaky Poorly fitted Gray to white soils Characteristics Soil will penetrate in pores and cracks of rubber Holes in air hoses Connecting hoses do not attach correctly Metal Part Defects Dirty or milk stone Badly dented or damaged Pitted or corroded Open seams Characteristics Soil is observed on one or more parts Damage interferes with function of part Rust or darkened surfaces Broken joints and splits/cracks of metal Page 19

20 VM C STEPS IN THE CHEESE-MAKING PROCESS 1. Standardize the milk. 2. Pasteurize or heat-treat the milk. 3. Cool the milk. 4. Inoculate the product with starter bacteria and allow for ripening. 5. Add the rennet so curd can form. 6. Cut the curd and heat. 7. Drain the whey. 8. Texturize the curd. 9. Add dry salt or brine for taste. 10. Form the cheese into blocks. 11. Store and age the cheese. 12. Package it. Page 20

21 VM D TYPES OF CHEESE Name of Cheese Body and Texture Flavor Color Blue Semi-soft, pasty, and crumbly Tangy, peppery White marbled with blue-green mold Brick Semi-soft, flexible, small openings Mild and sweet Light yellow to orange Brie Soft, thin crust, creamy interior Mild to strong White crust and creamy yellow interior Mild Cheddar Firm and some openings Mild with nut-like flavor White to orange Sharp Cheddar Smooth and waxy Sharp with nut-like flavor White to orange Colby Soft, more openings than cheddar Mild White to orange Cream Soft and smooth Mild to slightly acid White to light cream Gouda Semi-soft to firm, smooth Mild with slight salt Creamy yellow with brown or red wax Page 21

22 Name of Cheese Body and Texture Flavor Color Feta Grainy texture, soft to semi-hard Tangy, salty flavor to a mild-sharp White Havarti Semi-soft, smooth with irregular openings Buttery, sweet to very sweet, slightly acidic Cream to yellow Monterey Jack Semi-soft to hard, small openings Mild to mellow White to light cream Mozzarella Semi-soft, plasticity Mild Creamy white Muenster Semi-soft, waxy Mild Yellow, tan, or white surface with creamy inside color Processed American Soft with no holes Mild to sweet Nearly white to orange Provolone Hard with stringy texture Smoky, salty to a bland Light golden yellow to a brown Romano Very hard, usually grated Salty and sharp Creamy yellow color Swiss Firm and smooth, with large round openings Sweet Pale yellow Page 22

23 VM E Yogurt STEPS IN YOGURT-, SOUR-CREAM-, AND COTTAGE-CHEESE-MAKING PROCESSES 1. Adjust the milk composition, and blend the ingredients. 2. Pasteurize the milk mixture. 3. Homogenize it. 4. Cool the milk. 5. Inoculate it with a starter culture. 6. Hold the milk. 7. Let it cool. 8. Add fruit and flavors. 9. Package it. Page 23

24 Sour Cream 1. Add the culture (Streptococcus lactis) to pasteurized light cream. 2. Incubate it at 72 F (22 C) until the desired flavor and thickness are reached. 3. Additional nonfat milk solids and stabilizers may be added. Cottage Cheese 1. Add a bacterial culture or food-grade acid (vinegar) to pasteurized milk. This will cause the separation of the milk solids from the whey. 2. Curds are formed and gently cut into pieces that allow the whey to be drained. 3. Curds are cooked and pressed to force out more whey. 4. Curds are rinsed, and salt is added. 5. Light cream dressing is added to achieve the desired finished product. Page 24

25 VM F BUTTER-MAKING PROCESS AND BUTTER PRODUCTS 1. Butter is made from pasteurized cream. 2. The cream is churned or shaken until the milk fat/butterfat is separated from the buttermilk. 3. After churning, the butter is rinsed and salted (if desired). 4. The excess buttermilk is removed. Butter Products Butter Whipped butter Clarified butter Cultured butter Page 25

26 VM G MARKETING OPTIONS FOR DAIRY OPERATIONS Milk Production Veal Beef Cattle byproducts Page 26

27 VM H REAL AND ARTIFICIAL DAIRY FOODS Margarine versus butter Whipped cream versus whipped nondairy topping Coffee creamer versus half and half Cheese versus nondairy cheeses Page 27

28 LS A Name Processing Dairy Products Purpose The purpose of this activity is to create sour cream. Objectives 1. Describe the steps in making sour cream. 2. Observe and explain the thickening of the milk products. Materials 1 cup of cream 1 tablespoon of cultured buttermilk double boiler hot plate thermometer cold water bath spoon plastic wrap writing utensil paper Procedure 1. In a double boiler, bring the fresh cream to 180 F (82 C). 2. Cool to room temperature in a cold water bath. 3. Add the buttermilk. 4. Cover. 5. Let sit at room temperature for 24 to 48 hours. 6. Stir and refrigerate the product. 7. It will last for three to four weeks, if refrigerated. Page 28