ChaltaFarm Milk Powders and Dairy Export Department

Introduction

Cleaning and hygiene are essential in milk powder processing. Dairy equipment can accumulate residues from proteins, fats, sugars, and minerals, while inadequate cleaning can create conditions that increase contamination risks.

Cleaning-in-Place (CIP) systems allow tanks, pipelines, heat exchangers, pumps, and other process equipment to be cleaned without dismantling them. However, milk powder production also includes dry processing areas where introducing unnecessary water can create additional hygiene risks. For this reason, effective plant hygiene requires both appropriate CIP procedures and controlled dry-cleaning practices.

What Is CIP in Dairy Processing?

Cleaning-in-Place, or CIP, is a cleaning method in which water and cleaning solutions are circulated through process equipment without dismantling it.

The effectiveness of CIP depends on several factors, including cleaning time, temperature, chemical concentration, and flow conditions. These parameters must be selected according to the equipment and the type of residues being removed.

Why Is Cleaning Important in Milk Powder Processing?

Milk residues can become difficult to remove, particularly after exposure to heat. Proteins can undergo heat-induced changes, fats can become more difficult to remove, and mineral deposits may accumulate on equipment surfaces.

Effective cleaning helps remove these residues, maintain hygienic food-contact surfaces, support equipment performance, and reduce conditions that may contribute to microbial contamination. Codex recommends that cleaning and sanitation programmes be designed, monitored, and verified for their effectiveness.

How Does a Typical Dairy CIP Cycle Work?

The exact CIP programme varies according to the equipment, product, and type of soil. A typical dairy cleaning sequence may include the following stages.

1. Product Recovery and Pre-Rinsing

Remaining product is recovered where possible, followed by a water rinse to remove loose residues before chemical cleaning.

2. Alkaline Cleaning

Alkaline detergents, commonly based on sodium hydroxide, are used to remove organic residues such as proteins and fats.

3. Intermediate Rinsing

The system is rinsed to remove loosened residues and remaining alkaline cleaning solution.

4. Acid Cleaning

Acid cleaning is used to remove mineral deposits and other residues that may accumulate, particularly on heated equipment.

5. Final Rinsing and Disinfection

The equipment is thoroughly rinsed to remove cleaning chemicals. Where required, thermal or chemical disinfection is then applied according to the sanitation programme.

What Types of Residues Are Found in Dairy Equipment?

Different residues require different cleaning approaches.

Proteins

Heat exposure can make protein deposits more difficult to remove because of changes in protein structure.

Fats

Milk fat requires effective alkaline cleaning and can become more difficult to remove after exposure to high temperatures.

Minerals

Mineral deposits are generally addressed through acidic cleaning.

Heat-Induced Deposits

Evaporators, heat exchangers, and other heated equipment can develop deposits that require specific cleaning programmes.

CIP Challenges in Milk Powder Processing

Milk powder plants contain both liquid-processing and dry-processing areas.

Tanks, pipelines, evaporators, and heat-treatment equipment can be incorporated into CIP systems. In contrast, dry powder-handling areas require greater control of moisture.

Codex recommends keeping milk-processing areas as dry as possible and notes that inappropriate wet cleaning can contribute to contamination through water and aerosols.

Why Is Dry Cleaning Important in Milk Powder Production?

Milk powder is a low-moisture food, so unnecessary water should be avoided in dry processing environments.

Dry-cleaning methods can be used to remove powder residues and debris without introducing unnecessary moisture. The FDA also recognizes dry cleaning as an important sanitation approach in certain low-moisture food operations.

The appropriate method depends on the equipment, contamination risk, and validated sanitation programme.

CIP vs. Dry Cleaning in Milk Powder Plants

CIP and dry cleaning serve different purposes and should not simply be treated as interchangeable methods.

The correct method depends on equipment design, residue characteristics, and the plant's food safety and sanitation procedures.

Cross-Contamination in Milk Powder Processing

Cross-contamination is an important consideration in dry milk powder production because microorganisms can potentially transfer between contaminated surfaces, equipment, cleaning tools, and product.

A 2025 study in Applied and Environmental Microbiology investigated Salmonella cross-contamination on a milk powder production line and evaluated interventions such as product flushing and dry towel wiping. The study showed that the effectiveness of cleaning interventions can depend on the contamination scenario.

A 2026 study in Food Microbiology also examined Salmonella transfer and dry-cleaning interventions in milk powder production environments, highlighting the importance of controlling contamination pathways in dry areas.

Key Factors That Affect CIP Effectiveness

Time

Cleaning solutions need sufficient contact time with the residues.

Temperature

Temperature influences both cleaning chemistry and the properties of dairy residues.

Chemical Concentration

The concentration and type of detergent must be appropriate for the residue being removed.

Flow and Mechanical Action

Adequate flow helps provide the mechanical action required to remove deposits from equipment surfaces.

Equipment Design

Equipment must be designed so that cleaning solutions can reach the relevant food-contact surfaces.

Monitoring and Verification

Completing a CIP cycle does not by itself demonstrate that cleaning has been effective.

Codex recommends monitoring and verifying cleaning and disinfection programmes. Procedures should define the areas and equipment covered, cleaning methods, frequency, responsibilities, and verification activities.

For milk powder plants, verification should be appropriate to the equipment, product, and food safety programme.

Best Practices for Milk Powder Plant Hygiene

A practical hygiene programme should:

1. Match the cleaning method to each equipment and processing area.

2. Use validated CIP parameters for equipment designed for CIP.

3. Keep dry processing areas as dry as reasonably possible.

4. Use appropriate dry-cleaning methods where water could increase contamination risks.

5. Prevent cleaning tools from becoming a source of cross-contamination.

6. Monitor and verify cleaning effectiveness.

7. Maintain equipment so that food-contact surfaces can be effectively cleaned.

Conclusion

CIP is essential for maintaining hygienic conditions in tanks, pipelines, heat-treatment equipment, and other CIP circuits used in milk powder processing. However, milk powder production also requires careful moisture control in dry processing areas, where appropriate dry-cleaning practices can help reduce cross-contamination risks. Combining effective CIP procedures, controlled dry cleaning, hygienic equipment design, and proper sanitation verification supports consistent hygiene across dairy products and processing environments.