Different Classifications of Milk and Their Processing Equipment
Milk is among the most versatile foods in the Indian diet. Beyond being a nutrient-dense food, it is also the base for countless dairy products. This article explains the major milk types recognized in India and the dairy processing equipment used at every step, from raw milk reception to packaging.
How is Milk Classified?
FSSAI defines Milk as-“Milk” means the normal mammary secretion derived from complete milking of healthy milch animal, without either addition thereto or extraction therefrom, unless otherwise provided in these regulations and it shall be free from colostrum.
To deliver safe, consistent, and purpose-fit milk to consumers, dairies classify milk by composition (fat and solids-not-fat/SNF), source (species), and processing method (e.g., pasteurized, UHT, recombined).
Different Types/Classifications of Milk
Milk is one of the most widely consumed nutritious foods globally. The dairy processors procure milk from different dairy farmers who have a variety of sources, including cow, buffalo, goat, and sheep. Each animal produces milk with unique characteristics, but an equally important factor is the stage of lactation, which significantly influences both volume and composition.
Early lactation typically yields higher quantities but with variable fat and protein levels, while late lactation milk becomes richer but more limited. The seasonal shifts also impact milk production such as temperature, humidity, feed availability, and stress levels of the animals.
Each type of milk differs in its fat content, composition, and method of preparation. Below are the key classifications of milk and their defining characteristics:
Milk
Milk is the natural mammary secretion obtained from the complete milking of healthy milch animals. It must be free from colostrum and contain no added or removed components unless permitted by regulations. It is a white, opaque liquid that contains fat as an emulsion, protein, a few minerals, and lactose along with certain minerals and soluble proteins.
Full Cream Milk
Full cream milk is milk sourced from cow or buffalo milk in which the natural cream is retained, typically containing fat and SNF as per the table given below. The standardized full cream milk ensures consistent nutritional values across batches by adjusting milk solids. It offers a rich mouthfeel and is energy-dense. It is commonly used for desserts, curd, and children's nutrition.
Toned Milk
Toned milk is produced by blending cow or buffalo milk with skimmed milk or by adjusting milk solids to achieve the required fat and SNF levels. It offers a reduced-fat option while retaining essential nutrients, making it suitable for everyday consumption in tea, coffee, and general household use.
Double Toned Milk
Double toned milk is prepared similarly to toned milk but with further fat reduction using skimmed milk. It is ideal for calorie-conscious consumers who still want the benefits of milk proteins and minerals.
Standardized Milk / Mixed Milk
Standardized milk or Mixed milk is a combination of milch animals whose milk is adjusted to specific fat and SNF percentages using milk solids. It is generally received as a mixture of cow milk and buffalo milk to the dairy manufacturers. Further, they process it into different type of milk. And because of its consistent composition, it is preferred for balancing fat content, preparing paneer, curd, and various dairy products.
Recombined / Reconstituted Milk
Recombined / Reconstituted milk is prepared by homogenizing milk fat, non-fat milk solids, and water. It is commonly used in regions or seasons where fresh milk availability fluctuates to ensure consistent supply.
Skimmed Milk
Skimmed milk is produced by mechanically removing almost all milk fat. It contains negligible fat but retains proteins, calcium, and vitamins. While suitable for individuals on low-fat diets, it is not recommended for children who require dietary fats for growth.
Varied Fat Contents Across Different Type of Milk
| Class of Milk | Minimum Milk Fat | Minimum Milk Solids-not-Fat (SNF) |
|---|---|---|
| Cow Milk | 3.2 | 8.3 |
| Buffalo Milk | 5.0 | 8.0 |
| Sheep Milk | 3.0 | 9.0 |
| Goat Milk | 3.0 | 8.0 |
| Mixed Milk | 4.5 | 8.5 |
| Standardized Milk | 4.5 | 8.5 |
| Toned Milk | 3.0 | 8.5 |
| Double Toned Milk | 1.3 | 9.0 |
| Skimmed Milk | Not more than 0.5 | 8.7 |
| Full Cream Milk | 6.0 | 9.0 |
It is to be noted that pasteurization and UHT treatment is the common process through which all these classified milks go-through. Pasteurized milk is easily available in the market in different cold pouch sizes and uht treated milk is available in aseptic carton packs at ambient temperature. Also, the urea limits must not exceed 700 ppm and serve to give a negative Phosphatase Test that is applicable to milk immediately after pasteurization only.
Processing Equipment Used for Different Classifications of Milk
Dairy processors process different types of milk basis the changing consumer requirements. They choose the equipment that is best suited for the consumers health, taste, and functional preferences.
A. Milk / Full Cream Milk
- Clarifier to remove sediment
- Homogenizer
- HTST pasteurizer / UHT (depending on shelf-life target)
- Chilling & cold chain
B. Toned Milk
- Standardization skid blends whole milk and skim milk (or reconstituted solids)
- Cream separator
- Continuous agitators in balance tanks
- Homogenizer for consistent body
- HTST Pasteurizer
C. Double Toned Milk
- High-accuracy mass flow meters for tight fat targets
- Cream separator
- Homogenization to maintain body at low fat levels
- HTST; vigilant QA to ensure no solids deposition during storage
D. Standardized Milk / Mixed Milk
- Cream separator and standardization skid
- Homogenizer (optional, depends on downstream product)
- HTST Pasteurizer
E. Recombined Milk
- Powder handling (bag dump stations, conveyors), dissolvers
- Emulsification/homogenization for stable fat distribution
- HTST/UHT with aseptic or cold-chain packaging
Equipment Used Throughout Milk Processing
| Process | Equipment Used |
|---|---|
| Raw Milk Reception & Screening | Weighing scale, dump tank/receiver, inlet filters/strainers, chilling units, plate heat exchanger (PHE), inline milk analyzers (fat/SNF), sampling ports |
| Clarification | Centrifugal clarifier |
| Separation | Centrifugal cream separator |
| Standardization | Balance tanks, automated fat/SNF standardization systems, mass flow meters, blending skid with PLC |
| Homogenization | High-pressure homogenizer (typically 2-stage) |
| Heat Treatment | Pasteurization (HTST) & UHT |
| Hygiene | CIP (Clean-in-Place) |
In conclusion, by choosing the right composition and the right process, dairies can deliver safe, consistent, and purpose-built nutrition to consumers. Whether your priority is indulgent creaminess, calorie control, long shelf life, or functional formulation, modern dairy engineering ensures there’s a milk for every need and a proven process behind every pack.