Cheese production by Likhith K

Cheese is a very popular food produced worldwide from the milk of ruminants using a combination of physical treatments. Key milk components for the transformation of milk into curd are casein and calcium. The majority of cheese varieties are based on the curd of modified casein micelles that result from the enzymatic rennet clotting of milk in the presence of calcium ions. The remarkable ability of the spontaneous syneresis of rennet-induced curds can be adjusted to the desired level by biological acidification, cutting, stirring, heating, pressing and salting in order to achieve the desired level of water removal in the form of whey. The mode of curdling (acid or rennet coagulation), the conditions, and the combinations of curd treatments result in numerous cheese varieties with different appearances, textures, flavors and shelf lives. Moreover, most of them are kept under specific temperature and humidity conditions to ripen for a short or a considerable amount of time. The classification of cheese varieties is not unambiguous and can be based on various criteria. For example, cheeses can be classified according to their moisture content related to yield and shelf life or according to specific features related to the treatments applied during cheesemaking and ripening. During ripening, the main solid constituents of young cheese—fat and caseins—undergo changes that increase the concentration of small size compounds in cheese—such as peptides, amino acids, small volatile molecules—control moisture loss and configure textural properties. In particular, the compounds of mature cheese flavor result from complicated biochemical pathways that take place during cheese ripening or even storage.

1. CHEESE PRODUCTION by LIKHITH K BiSEP – 2021 Dept of Biotechnology St Aloysius College Mangaluru , Karnataka

2. CONTENTS Introduction Types of cheese Steps in cheese production Cheddar cheese and Production Nutritive value of cheese Cheese microbiota Benefits Conclusion References

3. INTRODUCTION Cheese is one of the oldest human foods and is developed approximately 8,000 years ago Word ‘cheese’ – Latin “ casues ”, meaning to ferment/become sour. The art of cheese making have traveled from Asia to the Europe and then spread all over the world. Ultimately a milk product. Widely used all over the world as food product. Purely a product of microbial fermentation A food consisting of the coagulated, compressed, and usually ripened curd of milk separated from whey. The curd of milk separated from whey, often seasoned and aged. A food derived from milk curd produced in a wide range of flavors, textures, and forms by the coagulation of the milk protein casein.

4. The cheese production is carried out from lactic acid fermentation of milk. T he enzymatic activity of rennin causes the coagulation of milk protein and formation of curd. After the curd is formed it is heated and pressed to remove the watery part of the milk, salted and then ripened . The organisms responsible for the manufacturing of cheese are Lactobacillus lactis, Propionibacterium sps . and Penicillium sps .

5. TYPES OF CHEESE 1) Fresh cheese 2) Soft cheese 3) Hard cheese

6. Fresh cheese: Requires high acidity by bacterial action. Cottage cheese Cream cheese

7. 2. Soft cheese: Requires slow acid development, washing to control lactose and minimal cooking time. Brie Camembert Gouda Mozzarella

8. 3. Hard cheese: R equires high acid development and high temperature. Cheddar Parmesan Edam

9. STEPS IN CHEESE PRODUCTION 1 . Curdling Milk Preparation Acidification Coagulation 2. Curd Processing Draining Salting Molding Others: Stretching, Chattering, Washing 3. Ripening

10. STEP I : CURDLING 1. Milk Preparation Heat treatment, filtration, and standardization

11. 2. Acidification Acidification of the milk is important for the proper release of whey from the cheese curd and to control the growth of many undesirable bacteria. Addition of starter cultures like lactobacilli. These microorganisms will ferment the carbohydrates present in milk into lactic acid NOTE: pH should be reduced to about 4.7, the optimum for milk coagulation. Lacto bacillus casei

12. Cheese chemistry

13. Cheese Starters and Adjunct Cultures Milk can be coagulated by heating, by the formation or addition of acid, by the use of a natural coagulant (such as rennet), or a combination of these treatment. Spontaneous acidification is caused by the growth of lactic acid bacteria (LAB), a diverse bacterial group the members of which generate lactic acid as the main end-product of lactose fermentation. The typical LAB are arranged into the genera   Lactococcus ,  Lactobacillus ,  Leuconostoc ,  and  Pediococcus . Via the action of complex anabolic and catabolic systems, the growth of LAB modifies the constituents of the milk (carbohydrates, proteins and lipids ). These modifications do not involve nutritional or sensorial losses; rather, they increase the bioavailability and diversity of nutrients and improve the quality and complexity of flavor profiles. LAB naturally present in milk or on manufacturing tools and in the environment are still relied upon in many traditional fermentations.

14. However, improvement in milk hygiene (mainly by refrigeration and pasteurization practices) and the need for standardization have promoted the generalized use of starters , i.e., selected strains of different LAB species deliberately added to the milk to control the fermentation and standardize the quality of the fermented product . Not surprisingly, in the search for improved starters, most microbial studies of cheese have focused on the isolation and characterization of new LAB strains of species such as   Streptococcus  ( S. )  thermophilus ,  Lactococcus  ( Lc . )  lactis ,  Lactobacillus  ( Lb. ) sp., and  Leuconostoc  ( Leuc . ) sp. In the industry, however, the term “starter” refers to all microorganisms added to the milk with a technological purpose, e.g., for improving the appearance, texture, and/or flavor of the final product, and thus also covers LAB species not involved in acidification, the so-called non-starter LAB (NSLAB ). In certain cheeses, it also covers bacteria of the genera  Propionibacterium  ( Emmental , Gruyère ),  Brevibacterium , and  Corynebacterium  (smear-ripened cheeses), molds and yeasts such as  Penicillium  ( P. )  roqueforti  (blue-veined varieties),  P. camemberti  (white moldy varieties ),  Geotrichum  ( G. )  candidum ,  Debaryomyces  ( D. )  hansenii  ( moldy and smear-ripened cheeses), and others. These secondary types of microorganisms are usually referred to as adjunct and/or ripening cultures 

15. CASEIN A white, tasteless, odorless protein precipitated from milk by rennin. Responsible for the white color of milk, which is due to the light reflected by the micelles. It makes milk a colloidal dispersion.

16. 3 . Coagulation of Milk Coagulation of milk is an important step in cheese manufacturing. T he casein fraction of the milk forms a gel . This can be achieved by lowering the milk pH and the addition of “rennet”, a mixture of specific proteolytic enzyme.  The most commonly used rennet contains the enzyme chymosin

17. STEP II : CURD PROCESSING 1 . Draining Cutting of curd into small cubes to allow water to drain from individual pieces of curd. Expulsion of whey results in shrinkage accompanied by further degradation of κ-casein, which may lead to the formation of new crosslinks in the rennet gel or curd and the development of a firmer or more rubbery curd.

18. 2. Salting Influences flavor, moisture and texture The salt can be added either directly to the curd after the whey is run off and before moulding or pressing into shape, or by immersing the shaped cheese block in salt brine for several days following manufacture. Salting also causes the removal of whey and slows down the rate of acid development as well as inhibits growth of undesirable bacteria.

19. 3 . Manipulation of Curd (a)   Heat Treatments : The application of heat to cheese curd  is to selectively stop the growth of certain types of bacteria  It also alters the composition and texture of the cheese by increasing the syneresis without increasing the acidity . (b)Stretching Stretching the curd is an important operation for several kinds of cheese. Traditionally the curd is immersed in hot water and the fluid mass of cheese is pulled into strands to align the protein fibres and then poured into a container to cool. It is then immersed in brine. (c) Cheddaring It is a mild form of stretching in which the cheese curd is piled up and held warm so that it flows under the force of gravity. It is periodically turned to flow again. The pH of the curd falls during this process and whey continues to exude

20. (d) Washing Washing help to remove more lactose which changes the pH of the cheese and reduces syneresis . (e) Molding or Shaping Most cheeses achieve their final shape when the curds are pressed into a mold. During molding , the curd is comminuted and shaped in a mold using a hydraulic press.

21. STEP III : RIPENING Ripening is the ageing and maturing of cheese. Lasts from a few days to several years. As a cheese ages, microbes and enzymes transform texture and intensify flavor. This transformation is largely a result of the breakdown of casein proteins and milk fat into a complex mixuture of amino acids, amines, and fatty acids.

22. CHEDDAR CHEESE A relatively hard, pale yellow-to-off white (unless artificially colored) sometimes “sharp” tasting natural cheese.

23. PRODUCTION Pasteurization Cheddar cheese can be made both from raw or heat treated milk. For Cheddar Cheese heat treatment (temperature) /time is usually 72-73 oC /15-20 seconds. Starter culture High amount of starter culture is need because of fast acidification required in cheddar making. In production of cheddar cheese the lactic acid producing starter culture is Streptococcus lactis . Renneting Rennet is an enzyme that is traditionally collected from the stomach of a milk-fed calf (natural rennet). This enzyme is responsible for the coagulation of the milk proteins to produce curds.

24. Setting the Curd Once the rennet is added, the mixture must be allowed to set and form curds. The mixture is kept at around 29 to 31 °C (84 to 88 °F ). Cutting the curd For Cheddar cheese the cut size is relatively small 5-10 mm, typical for hard cheeses . Cooking the curd The curd is cooked by adding hot water to the jacket of the vat (up to 39 °C or 102 °F). The curd is stirred constantly during this step to avoid uneven cooking or overcooking, and the cooking will only take 20–60 minutes. The whey's pH will be around 6.1 to 6.4 by the end of the cooking . Draining the curds Whey is removed from the curds by allowing it to drain out of the vat

25. Cheddaring The curd, after heating, is kneaded with salt, cut into cubes to drain the whey and then stacked and turned. It is a multi-step process that reduces whey content, adjusts acidity, adds characteristic flavour , and results in a denser and sometimes crumbly texture . Milling the curd When the turning process is complete, the loaves must be cut down into a size that fits in the mill. The mill will cut the matted curd into about 1.3 cm pieces . Mixing Salting is performed in cheddar cheese making by mixing dry salt with broken or milled curd at the end of manufacture The salt retards the growth of lactic acid bacteria. The curd is salted, and the salt curd mixture is pressed in molds. It helps to have a normal close texture of cheese and is done for 30 min at 40ºC Waxing/packaging The pressed cheese is wrapped in plastic foils

26. NUTRITIVE VALUES Cheese is a great source of calcium, fat, and protein. It also contains high amounts of vitamins A and B-12, along with zinc, phosphorus, and riboflavin. Cheese made from the milk of 100 percent grass-fed animals is the highest in nutrients and also contains omega-3 fatty acids  and vitamin K-2 Brie (1 ounce) Share on Pinterest 100 calories 1g carb 9g fat 5g protein 150mg calcium 170mg sodium

27. Cheddar (1 ounce) Share on Pinterest 120 calories 1g carb 10g fat 7g protein 200mg calcium 190mg sodium Feta (1 ounce) Share on Pinterest 60 calories 1g carb 4g fat 5g protein 60mg calcium 360mg sodium

28. Gouda (1 ounce) Share on Pinterest 110 calories 1g carb 9g fat 7g protein 200mg calcium 200mg sodium Mozzarella (1 ounce) Share on Pinterest 85 calories 1g carb 6g fat 6g protein 143mg calcium 138mg sodium

29. Swiss (1 ounce ) 100 calories 1g carb 9g fat 5g protein 150mg calcium 170mg sodium Note : One ounce of cheese is about the size of a 1-inch cube. All cheeses above are full-fat versions.

30. CHEESE MICROBIOTA Whether fermented in a natural manner, or with the aid of starter and/or adjunct cultures, most cheeses contain a complex mixture of microbial populations—including technologically-relevant, spoilage, opportunistic and pathogenic organisms—that develops and changes throughout manufacturing and ripening. All these microbes constitute the microbiota of the cheeses. Both intrinsic (substrates, vitamins, cofactors, the presence of inhibitory/activator compounds, pH, redox potential) and extrinsic factors (oxygen availability, temperature, salt, relative humidity) drive the numbers and spatial and temporal distribution of the members of the microbiota . The populations of the microbiota are composed of prokaryotic  Archaea  and  Bacteria , eukaryotic yeasts and fungi, and viruses (mainly bacteriophages ). The microbiota of cheese can be as simple as that of yogurt and other kinds of fermented milks, with perhaps just one or a very small number of LAB species present, such as in Petit-Suisse ( S. thermophilus  and  Lb. delbrueckii  subsp.  bulgaricus ) and Quark ( Lc . lactis  subsp.  lactis  and  Lc . lactis  subsp.  cremoris ).

31. More often, however, the cheese microbiota is composed of a consortium of diverse microorganisms and varies widely from one variety to another, although the dominant microbial types for each cheese type (soft, hard, natural rind, smear-ripened, blue-veined, etc.) are usually similar. The microbiota becomes particularly complex in blue-veined and smear-ripened varieties. As in other ecosystems, the diversity of the microbiota in cheese is governed by classical ecological processes, such as dispersion, diversification, environmental selection, and ecological drift . Microbial diversity and numbers are also influenced by the environmental interaction of biotic (natural fermentation, use or not of starters, presence of contaminating microbes and microbial metabolites) and abiotic factors (technological processes and environmental conditions), which modulate the implantation, development and, more importantly, the activity of the different microbes. Together , these variables determine the growth and function of the microorganisms and, therefore, some of the key biochemical changes they drive during ripening that lead to the unique appearance, texture, aroma and taste properties of each cheese variety, as well as their safety quality.

32. Cheese bacteria belong mainly to the phyla  Firmicutes  (LAB, enterococci , staphylococci),  Actinobacteria  ( corynebacteria , propionibacteria , bifidobacteria ), and  Proteobacteria  ( enterobacteria ). The archaeal taxa include members of  Thermocladium , Sulfurisphaera , Methanohalobium ,  and others; these are minority populations (< 0.5% relative abundance) and have only ever been detected by molecular methods . Among the eukaryotes, the dominant yeasts belong to the genera  Geotrichum , Debaryomyces , Kluyveromyces , Candida,  and  Yarrowia , and the filamentous fungi are molds such as  P. camemberti , P. roqueforti  and other  Penicillium  species, which are abundant in mold -ripened cheese varieties . Other filamentous fungi such as  Fusarium domesticum , Scopulariopsis  ( Sc. )  flava  and  Sc. casei  are also found in low numbers on the surface of most cheeses. Except for  P. roqueforti , all these other mold species are only known from cheese, suggesting they are adapted (“domesticated”) to this particular habitat. In particular,  P. camemberti  derives from the wild ancestor  Penicillium commune  in a quick adaptation process that involves reduced reproductive output, reduced mycotoxin production, reduced pigmentation and, significantly, a change in the volatile compound profile from earthy to cheesy .

33. The genetic basis of this rapid “evolution” has proven to be through gene regulation instead of genome changes.   Lc . lactis  subpopulations of the  lactis  and  cremoris  subspecies in dairy environments are also thought to be adapted through domestication processes . These , and the domesticated strains of other LAB species found only in milk and dairy products, seem to have emerged recently due to the selective pressure imposed by the dairy technologies. Though highly variable between varieties, the concentration of bacteria in ripened cheese may exceed 10 9  colony forming units ( cfu )/g , while those of yeasts and filamentous fungi range widely between 10 2  and 10 7   cfu /g. Depending on the microbial taxon , maximum numbers are reached by the end of the fermentation (e.g.,  Lc . lactis ), between day 7 to 17 (e.g.,  Lactobacillus  spp.) after one to two months of ripening (e.g., filamentous fungi). Once the highest level is reached, numbers are declining slightly but consistently afterward. Variations in the composition and/or dynamics of the microbial communities making up the typical microbiota of a given cheese can lead to serious technological and sensorial defects and even pose food safety risks.

34. BENEFITS 1. Cheese Can Prevent Osteoporosis 2. Cheese Can Have a Positive Effect on Your Dental Health 3. Cheese Consumption Can Help You Gain Weight in a Healthy Way 4. Cheese is the Best Dietary Source for Calcium 5. Cheese is an Excellent Source of Protein 6. Cheese is High in Vitamin B12 7. Cheese Can Reverse Hypertension by Lowering Blood Pressure 8. Cheese Provides the Essential Fat, CLA 9. Cheese Can Help Prevent Common Cancers 10. Cheese is Plentiful in Healthy Fats 11. Cheese is a Good Choice for Pregnant Women 12. Cheese Helps You Build Muscle 13. Cheese Benefits the Immune System 14. Cheese is Abundant in the Vital Vitamin K2 15 . Cheese is Good for Your Thyroid Health

35. CONCLUSION Cheese making has been in practice for over 8,000 years by various cultures around the world. Throughout history, many animals have been valued for their milk, including camels, bison, goats, and yaks. Today, the majority of dairy production comes from cow’s milk, increasing by 50% over the last 40 years. While the percentage of milk consumption in liquid form has decreased, the popularity of cheese has been on the rise, with each person eating an average of 34 pounds a year as of 2012. However, not all cheeses are created equal. Most cheeses get a bad rap. We hear about how it is unhealthy, negatively contributing to our waistline and increasing the number on the scale. While all cheeses should be eaten in moderation, there are some that are a good addition to your shopping list, including swiss , feta, part-skim mozzarella, parmesan, and cottage cheese. These are a great source of many essential vitamins and minerals, and can help you avoid common health issues.

36. REFERENCES Jay J M,Lossener M J,Golden D A,2005,7 th edition,Modern food microbiology,An Aspen Publications. Adams M R, Moss M O,2003,Food Microbiology,New Age International Publishers. Potter N N , Hotchikks H J, 1996,5 th edition,Food science, CBS Publishers. Yerlika O, Ozer E, july-sept 2014, Production of probiotic fresh cheese using co-culture with Streptococcus thermophilus , Food science and technology , Campinas,34(3):471-477 . Nassar.K , et.al., (2015); The production of Cheddar cheese; ResearchGate; pp: 1-9 Google images

37. Thank you