How to Clean Stainless Steel Tanks to Meet Sanitary Standards

Proper cleaning and sanitizing is an essential part of any industrial manufacturing process. Whether you’re manufacturing flavorings, sauces, lotions, or construction adhesive, having a defined cleaning procedure in place helps maintain product quality, consumer safety, and alignment with sanitary standards in regulated industries. 

While the terms are often used together or interchangeably, cleaning and sanitizing serve different purposes. Cleaning focuses on the physical removal of soils, residues and contaminants from surfaces. Sanitizing or disinfecting reduces or eliminates the presence of bacteria and other microorganisms still present after a thorough cleaning. Because sanitizers are only effective on clean surfaces, thorough cleaning is the foundation of a successful sanitation process. 

So how do manufacturers approach cleaning stainless steel tanks to meet strict sanitary standards? In this article, we’ll explore two common cleaning methods, when each method makes the most sense, and how to execute both in industrial processing. 

Industry-Standard Cleaning Methods for Stainless Steel Tanks

Over time, product can build up on tank walls, agitators, and internal fittings. When this happens, bacteria and biofilms can begin to develop, or ingredients may clump and harden in areas that are difficult to access during routine operation. Any ingredient left over doesn’t just create sanitation concerns, it can also impact heat transfer, reduce mixing efficiency, and affect overall process performance. Without a consistent cleaning procedure in place, these risks then increase with each production cycle. 

There are two common options for tank cleaning and sanitation in most manufacturing industries: Clean-In-Place (CIP) and Clean-Out-Of-Place (COP). The right solution depends on how a manufacturing process is designed, the amount of equipment being cleaned, and the characteristics of both the process materials and the cleaning solutions. 

Clean-In-Place (CIP) Process

Clean-In-Place is the cleaning of tanks and process equipment without disassembling them. As the name implies, the equipment is left in place and typically requires no manual intervention. A CIP process is automated and carried out while the tank and all components remain connected to the tank. 

Typical CIP systems use a combination of integrated spray balls or nozzles, cleaning solutions, controlled rinse cycles, and programmable control systems to circulate cleaning fluids throughout a tank. CIP processes are designed to consistently clean internal surfaces, including areas that are difficult to access manually. 

CIP is especially beneficial for larger tanks and complex mechanical systems. Because the process is automated, it provides:

• Consistent and measurable cleaning results
• Reduced labor requirements
• Shortened downtime between production cycles

For operations with frequent recipe changeovers or strict sanitation requirements, CIP can be an efficient and repeatable solution. 

Clean-Out-Of-Place (COP) Process

Clean-Out-Of-Place involves removing components from the tank or process system and cleaning them in a separate wash station. This method is commonly used for smaller parts such as agitator shafts and impellers, spray nozzles, gaskets, and other removable accessories. 

Because components are cleaned outside of the tank, COP allows for visual inspection and hands-on cleaning. This makes it easier for operators to identify buildup, wear, and damage that may not be visible in an automated cleaning process. COP can also be performed with minimal disruption to the rest of the process, especially when only specific parts require cleaning. 

In many cases, COP is used alongside CIP rather than as a replacement. The decision to use COP or CIP depends on tank design, auxiliary equipment involved, and the specific residue or product left behind in the process. Sticky, hardened, or highly viscous materials may require more manual attention to ensure thorough removal. 

How to Clean and Sanitize a Stainless Steel Tank

Whether cleaning is done “in-place” or “out-of-place,” the effectiveness of any sanitation effort ultimately comes down to the execution. Following a consistent and well-defined cleaning process helps ensure stainless steel tanks are cleaned properly and safely every time.

Let’s walk through the tank and mixer cleaning process step by step. 

1. Preparing for Cleaning

• Verify the tank is empty. Drain any residual contents.

• Ensure lockout/tagout procedures are in place. 

  • Especially important with mechanical components like agitators or pumps.

• Choose the right cleaning solutions and tools based on contaminants and equipment. 

2. Pre-Rinse

• Rinse interior surfaces with warm water to remove loose product and surface soils. 

3. Apply Cleaning Solutions

• Apply appropriate detergents or solvents. 
  • Alkaline cleaners for organic residues; acidic cleaners for mineral scale.
• Follow all recommended contact times, temperatures, and safety considerations when using cleaning solutions. 

4. Automated and Manual Cleaning

• In CIP: Use spray balls or nozzles to distribute the solution evenly on all surfaces. 
• In manual cleaning: Use brushes, pads, or jets on accessible surfaces.
• Pay special attention to corners, welds, and under agitator components.

5. Thorough Rinse

• Flush out detergents thoroughly to avoid carry-over that can interfere with final sanitation.

6. Sanitization (if applicable)

• Apply appropriate sanitizers after cleaning to control microbes and ensure sterile conditions.
• Use correct dilution and contact time to preserve materials of construction and guarantee sanitization.

7. Final Rinse and Dry

• Rinse with potable water and inspect visually or with surface testing tools to confirm cleanliness. 
• Verify the tank is dried thoroughly to prevent bacterial regrowth.

Inspecting and Validating Cleanliness of Mixing Systems

After cleaning and sanitization cycles are complete, the final step is confirming the process was effective. Inspection and validation help ensure all surfaces are clean and ready to begin the next production cycle. 

Verification starts with a visual inspection. Is there any visible residue or buildup on the tank walls, pipe fittings, or other internal connections? In applications with stricter sanitation requirements, methods such as ATP (adenosine triphosphate) testing, which measures actively growing microorganisms, or microbial swabs may be necessary to provide confirmation of cleanliness. 

Documenting cleaning cycles and inspections is equally important. Clear records support audit requirements and help teams track performance over time. When issues do arise, proper documentation makes it easier to identify gaps and refine cleaning procedures moving forward. 

Maintenance Tips for Tank and Mixer Sanitation

Maintaining sanitary conditions between scheduled cleanings helps reduce buildup, extend equipment life, and improve the effectiveness of future cleaning efforts. A proactive maintenance approach can minimize downtime and prevent issues before they occur. 

• Inspect all surfaces regularly. 
  • Check tank walls, weld, and internal fittings for signs of corrosion, pitting, or surface damage that could trap product or harbor bacteria. 
• Monitor gaskets, seals, and wear components. 
  • Worn or damaged gaskets and seals can enable bacterial growth and product buildup. Regular inspection and replacement help maintain sanitary conditions and prevent leaks. 
• Maintain moving and mechanical components. 
  • Improperly lubricated and maintained moving components can introduce contamination into your process. Agitators, mixing shafts, and bearings should be properly maintained according to their specifications. 

Putting Tank Cleaning Best Practices Into Action

Properly cleaning stainless steel tanks and mixers is essential to maintaining sanitary operations, protecting product quality, and supporting safe, reliable operation. By understanding the difference between cleaning and sanitizing, selecting the right cleaning method for your system, and following a consistent process, manufacturers can reduce risk and improve overall process performance.

A well-designed strategy doesn’t stop at the cleaning cycle, though. Regular inspection, documentation, and preventative maintenance all play a role in keeping tanks clean and ready for production. When cleanability and sanitation is built into both equipment design and daily operations, maintaining compliance and consistency becomes much more manageable.