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Dried Milk Powders – Processing and Manufacturing

By PMG Engineering ·

Overview of Dried Milk Powders in the Food Industry

With a rising demand for convenience food and longer shelf-life dairy options, dried milk powders have become crucial in food manufacturing. This sector is expected to grow rapidly due to its ability to solve perishability challenges in dairy. As a key product in food processing and manufacturing, Whole Milk Powder (WMP) and Skim Milk Powder (SMP) are produced through a highly controlled evaporation and drying process.

Principle of Drying in Dairy Processing

Drying is a mass transfer process involving the removal of moisture by evaporation. In food technology consulting, it’s essential to understand that dry air interacts with moist food, absorbing water content. This moist air is then replaced with dry air until the desired dryness is achieved. This process is central to producing high-quality powdered dairy products.

Step-by-Step Manufacturing of Dried Milk Powder

1. Milk Reception

On arrival at the food processing plant, raw milk undergoes rigorous quality checks including fat, SNF (Solids-Not-Fat), acidity, temperature, antibiotic residues, and adulteration. Accepted milk is stored in chilled silo tanks below 5–7°C to maintain freshness.

2. Standardization

Fat and SNF levels in milk are standardized to meet regulatory norms. This is done by separating milk into cream and skim milk and recombining them using automated systems like the Standomat to achieve consistent fat content.

3. Pasteurization

Milk is pasteurized using HTST (High Temperature Short Time) method at 72.3°C for 15–26 seconds. Many food manufacturing consultants recommend extended pasteurization to prevent survival of pathogens like Mycobacterium avium subspecies paratuberculosis (MAP), which has been linked to Crohn’s disease.

4. Evaporation / Concentration

Evaporation reduces energy consumption in drying. Falling film evaporators are commonly used to concentrate milk up to 40–60% total solids. Vapors are removed and recompressed for efficiency. This step is key for cost-effective food plant engineering.

5. Spray Drying – The Core Technology

In spray drying, concentrated milk is atomized and sprayed into a hot-air drying chamber (180–200°C). Heavier particles fall to the bottom while finer particles are separated in a cyclone separator and filtered.

Advanced systems use two-stage spray drying with static and vibrating fluid beds to preserve powder quality and prevent overheating. This method yields high bulk density, spherical particles.

6. Alternate Drying Methods in Food Factory Design

Roller (Drum) Drying:

Milk is dried on steam-heated rotating drums, and the dry film is scraped off with a blade.

Advantages:

  • No need to heat large air volumes
  • Oxygen-free drying, preserving sensitive nutrients

However, it results in irregular, low-density powder particles, unlike spray drying.

Freeze Drying (Lyophilization):

In this premium method, milk is frozen and sublimed under vacuum. It retains vitamins, proteins, and bioactives, but is rarely used for milk powder due to high energy costs.

7. Packaging and Storage of Milk Powders

Despite their stability, milk powders must be protected from moisture, oxygen, heat, and light to maintain shelf life. Common packaging includes multi-wall plastic-lined bags (25kg) or bulk bins. Whole milk powders (WMPs) are prone to oxidation at high temperatures (>30°C).

Nutritional Value of Dried Milk Powder

Powdered milk retains:

  • Essential minerals: Calcium, Magnesium, Potassium, Zinc
  • Vitamins: A, D, E, K
  • Amino acids: Crucial for cell growth, immunity, and calcium absorption

These nutrients are preserved through precise evaporation and drying processes.

Conclusion: Consulting Expertise in Dairy Powder Processing

Partnering with an experienced food consultant or dairy processing consultant ensures:

  • Compliance with FSSAI and GMP standards
  • Efficient plant design and layout
  • Selection of optimal processing equipment
  • High-quality product development
  • Competitive cost modeling

Whether you're launching a milk powder manufacturing unit or optimizing your current setup, leveraging the right food consultancy services can accelerate success.

Frequently asked
What temperature should raw milk be stored at before powder processing?
In a milk powder plant, accepted raw milk is stored in chilled silo tanks below 5–7°C to maintain freshness. Before storage, every consignment undergoes rigorous quality checks covering fat, SNF (Solids-Not-Fat), acidity, temperature, antibiotic residues and adulteration. Only milk clearing these reception tests moves forward to standardization, so silo temperature control and reception testing together form the first quality gate of the process.
What pasteurization parameters are used for milk destined for drying, and why is extended pasteurization recommended?
Milk for drying is pasteurized by HTST (High Temperature Short Time) at 72.3°C for 15–26 seconds. Extended pasteurization is often recommended to prevent survival of pathogens such as Mycobacterium avium subspecies paratuberculosis (MAP), which has been linked to Crohn's disease. Choosing the holding regime is therefore both a food-safety and a product-liability decision in dried milk powder manufacturing.
Why include an evaporator before the spray dryer instead of drying the milk directly?
Evaporation ahead of spray drying substantially reduces energy consumption in the drying stage, which is why it is central to cost-effective milk powder plant engineering. Falling film evaporators are commonly used to concentrate milk up to 40–60% total solids, with vapours removed and recompressed for further efficiency. The concentrate then goes to the spray dryer, so less water has to be evaporated using hot air.
How does spray drying work for milk powder, and what powder quality does it give?
In spray drying, concentrated milk is atomized and sprayed into a hot-air drying chamber at 180–200°C. Heavier particles fall to the chamber bottom while finer particles are recovered in a cyclone separator and filtered. Advanced plants use two-stage spray drying with static and vibrating fluid beds to preserve powder quality and prevent overheating. The result is high bulk density, spherical particles.
When would roller drying or freeze drying be considered instead of spray drying?
Roller (drum) drying dries milk on steam-heated rotating drums, with the dry film scraped off by a blade. It avoids heating large volumes of air and gives oxygen-free drying that protects sensitive nutrients, but yields irregular, low-density particles unlike spray drying. Freeze drying (lyophilization) freezes milk and sublimes moisture under vacuum, retaining vitamins, proteins and bioactives, but is rarely used for milk powder due to high energy costs.
What packaging and storage conditions protect dried milk powder shelf life?
Although dried milk powders are stable, they must be protected from moisture, oxygen, heat and light. Common formats are multi-wall plastic-lined bags of 25 kg or bulk bins. Whole Milk Powder (WMP) is particularly prone to oxidation at temperatures above 30°C because of its fat content, so warehouse temperature control and barrier packaging are key design considerations for a milk powder facility.
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PMG Engineering. (2021). Dried Milk Powders – Processing and Manufacturing. PMG Engineering. https://pmg.engineering/Article/73/dried-milk-powders-processing-and-manufacturing/

https://pmg.engineering/Article/73/dried-milk-powders-processing-and-manufacturing/