A. MILK COMPOSITION AND NUTRITION
1. Major constituents of milk
Milk is a complex biological fluid containing water, milk fat, proteins, lactose, minerals, vitamins, enzymes, and other minor components. Their concentrations vary with animal species, breed, genetics, stage of lactation, nutrition, health, and environmental conditions.
2. Minor constituents of milk
Minor milk components include phospholipids, sterols, fat-soluble and water-soluble vitamins, enzymes, pigments, hormones, nucleotides, minerals, and other bioactive compounds. Their concentrations are generally much lower than those of water, lactose, fat, and protein.
3. Principal milk solids
The major non-water constituents of milk are milk fat, proteins, lactose, and minerals. The expression “true constituents of milk” is not a preferred modern scientific classification.
4. Nutritional quality of milk proteins
Milk proteins are considered high-quality proteins because they provide all essential amino acids needed by humans. The major milk proteins are caseins and whey proteins.
5. Calcium and phosphorus
Milk is an important dietary source of calcium and phosphorus. A significant proportion of these minerals is associated with casein micelles, while the remainder occurs in the soluble milk phase.
6. Trace minerals
Milk contains minerals such as iron, copper, zinc, iodine, selenium, and manganese, but their concentrations are much lower than those of calcium and phosphorus. Concentrations vary with animal nutrition, species, geographical region, and production system.
B. MILK TYPES, STANDARDIZATION AND PROCESSING
7. Classification of milk
Milk may be classified according to fat content, solids-not-fat (SNF), processing method, animal species, or intended use. Terms such as standardized, toned, double-toned, recombined, full-fat, reduced-fat, and skim milk have different legal meanings in different countries.
8. Processed milk
Common processed milk categories include pasteurized milk, UHT milk, sterilized milk, homogenized milk, flavored milk, fortified milk, and recombined milk. The legal definitions and processing requirements vary by jurisdiction.
9. Jersey milk
Jersey cattle generally produce milk with relatively high fat and total-solids concentrations compared with many dairy breeds. However, no breed can scientifically be described as having the highest milk-fat content under all production conditions.
10. Murrah buffalo milk
Murrah buffalo milk is generally characterized by high fat and total-solids content. Actual composition varies with genetics, lactation stage, feed, season, and animal health.
11. Pearson’s square method
Pearson’s square is a simple calculation method for determining the proportions of two ingredients required to obtain a desired concentration of a selected component, such as milk fat. It is useful in basic milk-standardization calculations.
12. Alkaline phosphatase test
The alkaline phosphatase (ALP) test is used as an indicator of adequate pasteurization of milk. ALP is more heat resistant than many vegetative pathogenic bacteria; therefore, adequate pasteurization should substantially inactivate it. The test is an indicator of process adequacy, not a complete substitute for process control. The FDA uses alkaline phosphatase testing within its Grade A milk framework.
13. Lactose
Lactose is the principal carbohydrate naturally present in mammalian milk. It is a disaccharide composed of glucose and galactose. It is substantially less sweet than sucrose; its relative sweetness depends on the analytical method and conditions.
14. Milk pigments
Carotenoids, particularly β-carotene, contribute to the yellowish color of milk fat, cream, and butter. Riboflavin contributes to the yellow-green fluorescence characteristic of whey.
15. Titratable acidity of milk
Fresh milk has measurable titratable acidity because of naturally occurring caseins, phosphates, citrates, dissolved carbon dioxide, and other buffering components. The numerical value depends on species, composition, analytical method, and standard. Therefore, a single acidity range should not be treated as a worldwide legal value.
C. PASTEURIZATION AND COUNTRY-SPECIFIC MILK STANDARDS
16. Pasteurization of milk
Pasteurization is a controlled heat treatment designed to destroy specified pathogenic microorganisms while causing relatively limited changes in milk quality.
A widely recognized example is:
- United States FDA Grade A PMO: 63°C for 30 minutes, or 72°C for 15 seconds, for applicable milk products.
- Other countries may prescribe equivalent or different validated time-temperature combinations.
Therefore, 63°C/30 min and 72°C/15 s should be identified as specific regulatory pasteurization schedules, not as a universal definition for every country or product.
17. Standardized milk
Standardized milk is milk whose composition is adjusted to meet a specified fat and/or SNF requirement. The numerical composition is country- and product-specific.
For example, an Indian standard may define standardized milk differently from a U.S., European, Canadian, Australian, or Nepali product. Therefore, the value should always be written as:
Standardized milk — [country/standard] — specified fat/SNF requirement.
18. Toned milk
“Toned milk” is primarily a South Asian regulatory/product category, particularly associated with India. It should not be presented as a universal international milk category. Where used, the required fat and SNF values should be attributed to the applicable national standard.
19. Double-toned milk
Double-toned milk is also a region-specific product category. Its composition should be quoted only with the applicable national standard, such as the relevant Indian requirement, rather than as a global definition.
20. Cream
Cream is the portion of milk relatively rich in milk fat obtained by separation or other permitted processing. Minimum fat content varies according to the type of cream and jurisdiction. Codex maintains an international standard for cream and prepared creams.
21. Butter composition
Butter is a milk-fat product consisting primarily of milk fat with water and small amounts of non-fat milk solids. Under the Codex Standard for Butter, standard butter has a minimum milk-fat content of 80% by mass and a maximum water content of 16%, subject to the standard’s provisions. National standards may differ.
22. Butter flavor
Butter flavor results from numerous volatile compounds. Diacetyl is particularly important in the characteristic flavor of cultured butter, but it is not the only compound responsible for butter flavor.
D. BUTTER, BUTTEROIL AND FROZEN DAIRY PRODUCTS
23. Butter color
The natural yellow color of butter is largely associated with carotenoid pigments transferred from milk fat. In some countries and products, permitted colors such as annatto may be used to standardize or modify color.
24. Butteroil
Butteroil is a highly concentrated milk-fat product produced by removing practically all water and non-fat milk solids from butter or other milk-derived materials. Codex includes butteroil within its milkfat-product standards.
25. Butteroil composition
High-quality butteroil contains a very high proportion of milk fat, generally around 99% or higher, but the exact minimum fat and maximum moisture/non-fat-solids requirements depend on the applicable national or Codex standard.
26. Ice cream
Ice cream is a frozen dairy or dairy-based product containing milk or milk-derived ingredients, with permitted sweeteners, stabilizers, emulsifiers, flavors, and other ingredients as applicable. Minimum milk fat, protein, total solids, stabilizer, and emulsifier levels vary among countries and product categories.
Therefore, values such as 10% milk fat, 3.5% protein, and 36% total solids should be labelled as a specific national standard rather than worldwide requirements.
27. Cheese
Cheese is produced by coagulating milk proteins and separating the resulting curd from whey. Coagulation may be achieved using rennet enzymes, acidification, starter cultures, heat, or combinations of these methods. Codex has a General Standard for Cheese and individual standards for several named cheeses.
28. Evaporated/unsweetened condensed milk
Evaporated milk is produced by removing part of the water from milk and applying an appropriate heat treatment. Codex has a specific Standard for Evaporated Milks (CXS 281-1971). National compositional requirements may differ.
29. Sweetened condensed milk
Sweetened condensed milk is manufactured by concentrating milk and adding sugar. The high dissolved-solids concentration lowers water activity and contributes to preservation. Codex has a specific Standard for Sweetened Condensed Milks (CXS 282-1971).
30. Condensed skim milk
Condensed skim milk products are manufactured from skim milk by removing water, with or without added sugar depending on the product. Fat, total-solids, sugar, and other requirements are product- and jurisdiction-specific.
E. MILK POWDERS AND TRADITIONAL DAIRY PRODUCTS
31. Whole milk powder
Whole milk powder is manufactured by removing water from milk and normally contains a relatively high proportion of milk fat. Codex maintains a Standard for Milk Powders and Cream Powder (CXS 207-1999). Moisture, fat, protein, acidity, solubility, and microbiological requirements should be taken from the applicable standard.
32. Skim milk powder
Skim milk powder is produced from milk from which most milk fat has been removed before drying. It contains high concentrations of milk proteins, lactose, and minerals relative to its low fat content.
33. Milk-powder drying methods
The major industrial methods are:
- Spray drying
- Roller/drum drying
Spray drying is widely used for commercial milk powders because it provides good control over powder particle characteristics and functional properties.
34. Solubility of milk powders
Milk-powder solubility depends on drying conditions, protein denaturation, particle structure, fat distribution, moisture, storage conditions, and reconstitution conditions. A numerical solubility-index limit must always be associated with the relevant analytical method and product standard.
35. Concentrated whole-milk products
Traditional concentrated dairy products include khoa/mawa, rabri, and some forms of kulfi. Their definitions, composition, and manufacturing practices vary among regions.
36. Fermented and coagulated dairy products
Dahi and shrikhand are fermented dairy products, while paneer and chhana are primarily acid-coagulated fresh dairy products. Product definitions and legal standards vary by country.
37. Traditional milk-fat products
Makkhan/butter and ghee are milk-fat products. Ghee residue is the solid residue separated during ghee clarification. Lassi, however, is a fermented or cultured milk-based beverage and should not be classified as a clarified-fat product.
38. Khoa/mawa
Khoa is a concentrated milk product manufactured mainly by heating milk and removing water. Its composition varies according to product type and national standard. A minimum of 20% milk fat should therefore not be presented as a worldwide requirement.
39. Khoa varieties
Traditional khoa varieties include pindi, dhap/dhar, and danedar, which differ mainly in moisture content, texture, grain formation, and manufacturing conditions.
40. Chhana and paneer
Chhana is obtained by acid coagulation of milk followed by whey separation. Paneer is produced by acid coagulation followed by pressing of the curd. Moisture and fat requirements are standard-specific.
F. GHEE, HYGIENE, ADULTERATION AND DAIRY DEVELOPMENT
41. Ghee
Ghee is a clarified milk-fat product produced by removing water and non-fat milk solids from milk-derived fat. Codex recognizes ghee as a milkfat product; national standards may specify additional composition and quality criteria.
42. Ghee residue
Ghee residue is the brown to dark-brown solid material remaining after clarification and filtration of ghee. It contains concentrated milk solids and other non-fat components and can be utilized as a food ingredient where permitted.
43. Diacetyl concentration in butter
Diacetyl concentration depends on starter culture, fermentation conditions, cream composition, processing, and storage. Therefore, a value such as 4 ppm should not be stated as a universal maximum unless a specific national standard or specification is cited.
44. Milk production by country
Milk-production rankings are time-dependent. A statement such as “India is the world’s leading milk producer” should be accompanied by the relevant year and authoritative production source. FAOSTAT or the relevant national statistical authority should be used for current rankings.
45. Dairy cleaning and sanitation
Cleaning removes milk residues such as fat, protein, lactose, and mineral deposits from equipment. Sanitation/disinfection reduces microorganisms to an acceptable level. Dairy plants require validated cleaning and sanitation programmes, appropriate chemicals, concentration control, temperature, contact time, mechanical action, and verification.
46. Milk adulteration
Potential milk adulterants include added water, starch, sucrose, urea, neutralizing agents, detergents, and other unauthorized substances, depending on the type of fraud and jurisdiction. Adulteration testing should use validated analytical methods and appropriate controls.
47. Dairy hygiene and milk safety
Milk safety depends on controls throughout the chain:
Animal health → hygienic milking → rapid cooling → clean transport → processing → packaging → cold storage → distribution.
Controls should address pathogens, antimicrobial residues, contaminants, cleaning chemicals, environmental contamination, and temperature abuse.
48. Milk-quality testing
Milk quality assessment can include:
- Fat
- Protein
- Lactose
- SNF/total solids
- Acidity and pH
- Microbial quality
- Somatic cell count
- Antibiotic/veterinary-drug residues
- Adulterants
- Contaminants
- Sensory quality
The required tests depend on the purpose, country, product, and regulatory framework.
49. Dairy research institutions
Dairy research is conducted worldwide by universities, government agencies, research institutes, international organizations, and industry. NDRI is a major dairy research institute in India, but it should not be described as the world’s leading dairy research institute without an objective ranking.
50. White Revolution
The term White Revolution is strongly associated with India’s rapid expansion of milk production and dairy cooperatives, particularly through Operation Flood. It is therefore primarily an Indian dairy-development concept. Other countries have developed their dairy sectors through their own agricultural, cooperative, technological, and policy systems.
COUNTRY-SPECIFIC STANDARD RULE
For examination or professional use, never write a numerical dairy standard without naming the country or standard when the value is not internationally uniform.
Example: Milk Fat/SNF
India — FSSAI:
Use the current FSSAI standard for the specific milk category. Do not automatically apply the Indian definitions of toned, double-toned, or standardized milk to another country.
Nepal — DFTQC:
Nepal has its own food and dairy requirements. A Nepalese source citing DFTQC standards reports minimum fat/SNF values for fresh cow milk of 3.5% fat and 7.5% SNF, and buffalo milk of 5% fat and 8% SNF. These are Nepal-specific values and should not be presented as international limits.
Nepal’s government also maintains a Milk and Milk Products Hygiene and Quality Directive, 2075, through DFTQC.
United States — FDA:
For applicable Grade A milk products, the FDA Pasteurized Milk Ordinance provides specific pasteurization combinations, including 63°C/30 min and 72°C/15 sec.
Codex:
Codex provides international reference standards for products such as butter, milkfat products, evaporated milk, sweetened condensed milk, cheese, cream, milk powders, and fermented milks.
European Union:
EU dairy requirements are established through EU legislation. The applicable legal requirement must be cited rather than substituting an FSSAI, FDA, or Codex number.
Canada:
Health Canada and CFIA requirements apply to Canadian dairy products. Canadian standards should be cited separately where a numerical composition or processing requirement is relevant.
Australia/New Zealand:
FSANZ Food Standards Code requirements apply. Australian/New Zealand dairy requirements should not be replaced with Indian, Nepali, U.S., or Codex values.
United Kingdom:
UK food legislation and FSA guidance apply. Requirements should be checked separately where a legal value is required.
HOW NUMERICAL VALUES SHOULD APPEAR IN FUTURE NOTES
Instead of writing:
Milk contains 3.5% fat.
Write:
Nepal — fresh cow milk: minimum 3.5% fat and 7.5% SNF according to the cited Nepalese standard source.
Instead of:
Pasteurization = 72°C for 15 seconds.
Write:
U.S. FDA Grade A PMO: 72°C for 15 seconds is one recognized pasteurization combination for applicable milk products. Other jurisdictions may prescribe equivalent or different validated schedules.
Instead of:
Butter must contain 80% fat.
Write:
Codex: Standard butter has a minimum milk-fat content of 80% by mass and maximum water content of 16%; national requirements may differ.
Scientific rule
Country standard ≠ worldwide scientific fact.
For your future Food Science & Technology notes, I will therefore separate every value into:
Scientific principle → Codex/international reference → India (FSSAI) → Nepal (DFTQC) → USA (FDA/USDA, where applicable) → EU → Canada → Australia/New Zealand → UK → other country-specific requirements where relevant.
If a country has no verified current numerical value available from an authoritative source, I will write “standard-specific — verify current national regulation” rather than inventing or transferring a number from another country.