A Cost-Effective Solution for Long-Life Dairy Beverage Manufacturing

Recombined UHT dairy beverages can help manufacturers produce consistent, affordable, long-life products in markets where the supply, quality or price of fresh milk changes throughout the year.

The product is generally prepared by combining milk powder, potable water, vegetable fat and other permitted ingredients. After correct mixing, hydration, emulsification and homogenization, it receives a validated UHT treatment and is filled into sterile, hermetically sealed aseptic cartons.

USM—Used Sweden Machines can source and supply used and professionally refurbished mixing, processing, homogenization, UHT, aseptic storage, filling and downstream packaging equipment for recombined dairy projects.

Important Product-Naming and Labelling Requirement

A product containing vegetable fat may not legally qualify as “milk” in every country.

The Codex General Standard for the Use of Dairy Terms controls how dairy names and descriptions are used. Local regulations may require a product in which milk fat is partially or completely replaced with vegetable fat to be described as:

Filled milk
Recombined filled milk
Dairy beverage with vegetable fat
Milk-based beverage
Blend of skimmed milk and vegetable fat
Formulated dairy beverage

The approved product name, ingredient declaration, nutrition information and package artwork must be verified in the intended country of sale before commercial production.

The product should never be presented as containing only dairy fat if vegetable fat has been added.

What Is Recombined UHT Milk?

Recombined dairy products are made by combining preserved milk ingredients with water and other permitted ingredients to produce a liquid product with the required composition.

Depending on the formulation, raw materials may include:

Skimmed milk powder
Whole milk powder
Milk protein ingredients
Whey ingredients
Potable process water
Milk fat
Edible vegetable fat or oil
Vitamins
Minerals
Stabilizers
Emulsifiers
Flavour ingredients

When skimmed milk powder is combined with water and milk fat, the product may be considered recombined milk, subject to local standards.

When milk fat is replaced partly or completely with vegetable fat, a different legal product classification may apply.

Why Use Milk Powder and Vegetable Fat?

More Consistent Raw-Material Supply

Milk powder can be stored for longer periods than raw liquid milk and can be sourced according to production demand.

This can help manufacturers operating in regions with:

Seasonal milk shortages
Inconsistent raw-milk quality
Limited milk-collection infrastructure
High transportation costs
Large variations in daily milk supply

Controlled Product Composition

Milk powder and fat can be dosed according to a standardized recipe, helping maintain consistent:

Fat content
Protein content
Total solids
Taste
Colour
Viscosity
Nutritional composition

Potential Cost Control

Vegetable fat may be more economical than dairy fat in certain markets. However, total cost depends on international commodity prices, import duties, formulation requirements and local labelling rules.

Long-Life Distribution

After validated UHT treatment and aseptic filling, the unopened product can be distributed under approved ambient-storage conditions.

Flexible Production

The same processing plant may be configured to manufacture:

Standard recombined beverages
Filled dairy beverages
Flavoured dairy drinks
Tea whiteners
Coffee beverages
Cooking cream
Whipping products
Fortified nutritional beverages

Each formulation requires its own process development and validation.

Selecting the Right Raw Materials

Milk Powder

The powder is the primary source of milk proteins, lactose, minerals and milk solids.

Important quality parameters may include:

Protein content
Moisture
Fat content
Solubility index
Heat classification
Scorched particles
Microbiological quality
Bulk density
Flavour
Storage history
Shelf life

Poor powder solubility can cause sedimentation, undissolved particles and processing difficulties.

The selected powder must be suitable for UHT treatment. A powder that performs well in a dry application may not necessarily provide acceptable heat stability in a liquid UHT beverage.

The Codex Standard for Milk Powders and Cream Powder provides internationally recognized compositional and quality provisions for milk powders.

Vegetable Fat or Oil

The selected fat must be food-grade and suitable for the intended beverage.

Important considerations include:

Melting profile
Solid-fat content
Oxidative stability
Flavour neutrality
Storage stability
Emulsification behaviour
UHT heat stability
Local food regulations
Nutritional requirements
Trans-fat restrictions
Compatibility with the required mouthfeel

A fat that remains excessively solid at consumption temperature may create a waxy mouthfeel. A highly unsaturated oil may require additional protection against oxidation.

The manufacturer must balance cost with flavour, nutrition, stability and consumer expectations.

Process Water

Water forms a major part of the finished product and directly affects quality.

It should be:

Potable
Microbiologically controlled
Free from objectionable taste and odour
Suitable for dairy processing
Consistent in mineral composition
Compatible with heat treatment
Properly monitored

Depending on source-water quality, treatment may include:

Filtration
Activated-carbon treatment
Softening
Membrane treatment
Ultraviolet treatment
Controlled disinfection

Unsuitable water chemistry can affect powder hydration, protein stability, taste and equipment fouling.

Stabilizers and Emulsifiers

Vegetable fat and water naturally tend to separate. An appropriate emulsification system may therefore be required.

Depending on the recipe and local regulations, functional ingredients may be used to support:

Fat dispersion
Emulsion stability
Protein stability
Viscosity
Suspension
Mouthfeel
Heat stability
Shelf-life performance

The type and dosage must be developed for the specific product. Excessive use can produce an unnatural texture or create labelling and regulatory problems.

Vitamins and Minerals

Products may be fortified to meet nutritional or commercial targets.

Fortification requires careful control because certain minerals can interact with milk proteins and reduce UHT stability.

Vitamins may also be sensitive to heat, oxygen and light. Formulation should account for processing losses and legal limits without adding unapproved overages.

Complete Recombined UHT Production Process

1. Water Preparation

The required quantity of treated water is transferred to the mixing system.

Water temperature should be controlled according to the powder supplier’s recommendations and the validated recipe. Water that is too cold may slow hydration, while excessive temperature can promote lumping or undesirable protein changes.

2. Milk-Powder Addition

Milk powder should be introduced gradually under controlled mixing.

Possible systems include:

Powder-induction units
Vacuum powder mixers
High-shear mixers
Inline blenders
Batch mixing tanks

The objective is to disperse the powder without creating:

Lumps
Excessive foam
Undissolved particles
Excessive air incorporation
Protein damage

Dust control and hygienic powder handling should also be considered.

3. Hydration

Milk proteins require sufficient time and suitable conditions to hydrate properly.

Incomplete hydration may cause:

Sedimentation
Grainy texture
Poor heat stability
Inconsistent viscosity
Reduced emulsion stability
Fouling in the UHT system

The hydration time and temperature must be established for the selected powder and formulation.

4. Vegetable-Fat Preparation

Solid or semi-solid vegetable fat must be melted under controlled conditions before incorporation.

The fat-preparation system may include:

Heated fat-melting tank
Temperature control
Agitator
Transfer pump
Inline filter
Insulated pipelines

Excessive heating can accelerate oxidation and cause undesirable flavour. Insufficient heating can leave solid fat particles and create an unstable emulsion.

5. Emulsifier and Stabilizer Preparation

Functional ingredients must be dispersed according to their technical requirements.

Some ingredients require:

Dry premixing
High-shear dispersion
Separate hydration
Controlled temperature
Specific order of addition

Incorrect addition can cause clumping or prevent the ingredient from functioning properly.

6. Fat Incorporation and Pre-Emulsification

The prepared vegetable fat is gradually introduced into the milk phase under controlled mixing.

The objective is to create a stable pre-emulsion before homogenization.

Poor pre-emulsification can result in:

Free oil
Fat separation
Floating cream layer
Unstable homogenization
Inconsistent product composition
Increased fouling

The mixing tank, agitator and high-shear system must be sized for the batch volume and product viscosity.

7. Composition Standardization

The blend is adjusted to meet the finished-product specification.

Important controls include:

Fat percentage
Protein
Total solids
Solids-not-fat
Brix, where relevant
Density
pH
Mineral balance
Viscosity

Water or ingredients should not be adjusted by estimation alone. Accurate weighing, flow measurement and laboratory testing are necessary.

8. Filtration and Deaeration

Filtration removes undissolved particles and foreign material before the product enters sensitive processing equipment.

Deaeration may be used to reduce entrained and dissolved air.

Removing excessive air can help reduce:

Oxidation
Foaming
Burn-on
Filling variation
Unstable homogenization
Package headspace problems

9. Preheating

The product is heated to a suitable temperature before homogenization and UHT treatment.

Preheating helps:

Prepare the fat phase for homogenization
Improve emulsion formation
Control viscosity
Improve heat-transfer efficiency
Support the validated thermal process

Actual conditions depend on the formulation and equipment configuration.

10. Homogenization

Homogenization reduces fat-droplet size and creates a more stable emulsion.

A two-stage homogenizer may be used to:

Disperse vegetable fat
Reduce cream separation
Prevent fat clustering
Improve mouthfeel
Create uniform colour
Support long-term physical stability

Homogenization pressure must be optimized. Excessive pressure can create protein instability, high viscosity or fat aggregation, while insufficient pressure may allow separation.

The correct homogenization temperature, pressure and number of stages must be established through trials.

11. UHT Treatment

The homogenized product receives a validated UHT treatment to achieve commercial sterility.

The system may use:

Direct steam injection
Direct steam infusion
Indirect plate heating
Indirect tubular heating

The choice depends on:

Product formulation
Protein content
Fat type
Heat stability
Desired flavour
Viscosity
Fouling behaviour
Production capacity
Utility costs

Direct systems can reduce the overall heat load on heat-sensitive products. Indirect systems can provide efficient heat recovery and lower operating costs.

The process must achieve the required microbiological result without creating:

Cooked flavour
Excessive browning
Protein precipitation
Sediment
High viscosity
Fat separation
Severe heat-exchanger fouling

The thermal process must be scientifically established for the specific formulation.

12. Aseptic Cooling

After UHT treatment, the product is cooled inside a closed sterile system.

Every downstream component must remain aseptic, including:

Product pipelines
Valves
Instruments
Pumps
Aseptic tank
Filling machine

Any recontamination after UHT treatment can compromise the entire production batch.

13. Aseptic Buffer Storage

An aseptic tank may be installed between the UHT system and filling machine.

It helps:

Balance processing and filling output
Maintain sterile product conditions
Reduce losses during short filler stops
Provide stable product flow
Support continuous UHT operation

Tank pressure, sterile-air supply, holding time, agitation and sterilization must be controlled.

14. Aseptic Filling

The commercially sterile product is filled into sterilized packaging material and hermetically sealed.

The filling process must provide:

Sterile packaging-material treatment
Controlled aseptic environment
Accurate filling volume
Reliable seals
Correct package formation
Batch coding
Production traceability
Package-integrity control

Available retail and food-service volumes may include:

100 ml
125 ml
200 ml
250 ml
500 ml
1,000 ml

Actual package formats depend on the configuration of the selected filling equipment.

15. Secondary Packaging

The line may also include:

Straw application
Reclosable-cap application
Date coding
Package inspection
Conveyors
Accumulators
Tray packing
Shrink wrapping
Case packing
Palletizing

Essential Quality-Control Tests

Raw-Material Testing

Milk-powder composition
Moisture
Solubility
Microbiological quality
Fat quality
Peroxide value or oxidation indicators
Water quality
Ingredient identity
Certificate-of-analysis verification

In-Process Testing

Fat
Protein
Total solids
pH
Density
Viscosity
Emulsion stability
Hydration
Homogenization performance
Heat stability

Finished-Product Testing

Commercial sterility
Package integrity
Fat separation
Sedimentation
Viscosity
Colour
Flavour
Oxidation
Nutritional composition
Incubation performance
Real-time shelf life

The Codex Code of Hygienic Practice for Milk and Milk Products emphasizes hygienic controls throughout the dairy chain to ensure product safety and suitability.

Common Production Problems

Oil Separation

Possible causes include unsuitable fat, inadequate emulsifier, poor pre-emulsification or insufficient homogenization.

Sedimentation

Possible causes include incomplete powder hydration, protein instability, mineral imbalance or excessive heat treatment.

Excessive Viscosity

This may result from high stabilizer dosage, protein interaction, excessive homogenization or heat damage.

Cooked Flavour

Possible causes include excessive thermal load, long holding time or unnecessary product recirculation.

Oxidized or Rancid Flavour

Possible causes include poor-quality fat, excessive oxygen, high storage temperature or insufficient protection from light.

UHT Fouling

Possible causes include unstable protein, incorrect mineral balance, excessive solids, poor hydration or unsuitable heating conditions.

Package Swelling

Swollen packages may indicate microbial growth, inadequate processing, recontamination or package-integrity failure. The affected production must be isolated and investigated.

Equipment Available Through USM

USM can source and supply refurbished equipment for complete or partial recombined UHT dairy lines.

Preparation and Mixing

Water-treatment equipment
Powder-induction systems
High-shear mixers
Mixing and hydration tanks
Fat-melting tanks
Ingredient-dosing systems
Inline blenders
Filters and product pumps

Processing

Preheaters
Deaerators
Homogenizers
Direct UHT plants
Indirect UHT plants
Aseptic tanks
Product-transfer systems
Cleaning-in-place systems

Filling and Packaging

Refurbished aseptic carton filling machines
Straw and closure applicators
Conveyors
Accumulators
Date-coding systems
Tray and case packers
Shrink-wrapping equipment
Palletizing systems

Equipment availability depends on the required product, package, capacity and current used-machinery market.

USM Project Services

Depending on the agreed scope, USM can coordinate:

Equipment sourcing
Technical evaluation
Configuration verification
Machine inspection
Professional refurbishment
Factory acceptance testing
Dismantling
Professional packing
International shipping
Installation supervision
Commissioning support
Operator training
Maintenance training
Initial spare-parts planning

Information Required for a Project Proposal

To recommend suitable equipment, USM normally requires:

Proposed legal product name
Product formulation
Milk-powder type
Vegetable-fat specification
Target fat and protein levels
Required unopened shelf life
Package volume and format
Required production capacity
Daily operating hours
Existing factory equipment
Available steam and cooling
Water-treatment capacity
Electrical standard
Destination country
Required installation scope
Target budget
Planned production date

Build Your Recombined UHT Dairy Line with USM

Successful production requires more than mixing powder, fat and water. Raw-material selection, hydration, emulsification, homogenization, heat stability, UHT processing and aseptic filling must be developed as one integrated system.

Planning a recombined UHT dairy project?

Share your formulation, package size, required production capacity and destination country with USM. Our team can help identify suitable refurbished processing, UHT, aseptic storage and filling equipment.

USM — Used Sweden Machines

Practical Processing. Refurbished Technology. Global Supply.

Technical and regulatory note: Product formulation, ingredient use, legal product name, heat treatment, commercial sterility and shelf life must be developed and validated by qualified dairy technologists, microbiologists and regulatory specialists. Regulations vary by country, particularly when milk fat is replaced partly or completely with vegetable fat.