How to Identify the Real Cause of Deformation in PC Tissue Culture Bottles After Autoclaving

How to Identify the Real Cause of Deformation in PC Tissue Culture Bottles After Autoclaving: A Customer Site Investigation Case

Introduction

In commercial plant tissue culture production, autoclaving is an essential step for preparing culture vessels before inoculation and cultivation.

PC tissue culture bottles, PP culture containers, and other tissue culture vessels are commonly required to withstand high-temperature and high-pressure sterilization conditions before entering the production process.

However, during actual production, some practical issues may occasionally occur.

For example:

• Some culture bottles may show slight deformation around the bottle mouth after autoclaving.

When this type of problem appears, the first questions are usually:

• Is there a problem with the bottle quality?
• Is the material performance insufficient?
• Are the autoclaving parameters incorrect?

These are reasonable considerations.

However, in commercial production environments, the real cause of a problem often cannot be determined only by looking at the final result. A systematic investigation of the entire process is usually required.

Recently, we encountered a case where a customer found deformation on the bottle mouth of PC tissue culture bottles after autoclaving.

Through multiple on-site inspections and elimination tests, we were able to identify the actual factor affecting the deformation.

Customer Feedback: Bottle Mouth Deformation After Autoclaving

During routine production, the customer noticed that some PC tissue culture bottles developed slight deformation around the bottle mouth after autoclaving.

After receiving the samples from the customer, we immediately inspected the affected bottles.

Based on the deformation characteristics, our initial judgment was:

The bottle mouth deformation was more likely caused by external pressure rather than a material issue.

PC material itself has good temperature resistance and is widely used in reusable tissue culture applications. Under normal autoclaving conditions, properly manufactured PC tissue culture bottles should maintain stable performance.

However, instead of making a conclusion only from the samples, we decided to visit the customer’s production site and investigate the complete operating process.

First Investigation: Checking Culture Basket Arrangement

After arriving at the customer’s facility, we first reviewed the autoclaving process.

The customer’s autoclave system included:

• 7 loading layers;
• 4 stacks arranged per layer;
• 28 stacks of culture containers in total.

During the inspection, we noticed that there was some space between the culture baskets and the PC tissue culture bottles.

Therefore, our first assumption was:

Could uneven support during loading cause concentrated pressure on certain bottle mouths?

If the culture baskets and bottles are not positioned properly, the weight from upper layers may transfer unevenly and create pressure points on individual bottles.

Based on this possibility, we adjusted the loading method:

• Reorganized the culture basket arrangement;
• Improved the alignment of the bottles;
• Tried to make the pressure distribution more uniform.

However, after another test cycle:

The bottle deformation still appeared.

This indicated that the arrangement method alone was not the main cause.

Second Investigation: Adjusting the Exhaust Time After Autoclaving

After excluding the loading arrangement factor, we continued analyzing other possible causes.

Another possibility was the pressure release process after autoclaving.

If the pressure changes too quickly after sterilization, plastic containers may experience stress caused by rapid pressure differences.

Therefore, we performed a second test.

The exhaust time was extended:

From 6 minutes to 12 minutes.

By slowing down the pressure release process, we aimed to reduce possible stress on the containers.

However, the test result showed:

Some bottles at the bottom area still developed deformation.

Based on this result, we could basically exclude exhaust speed as the main factor.

Third Investigation: Eliminating the Influence of the Breathable Membrane

To further investigate the issue, we continued checking the ventilation system.

Since the breathable membrane affects gas exchange between the inside and outside of the container, we considered whether the ventilation condition could influence the deformation.

Therefore, we adjusted the breathable membrane condition and performed another test.

The result showed:

Even after changing the ventilation condition, deformation still appeared on some bottles located at the bottom area.

At this stage:

The breathable membrane factor could also be excluded.

Final Finding: The Problem Was Related to the Autoclave Support Structure

After several rounds of testing, we returned to the original observation:

The deformation pattern was still consistent with external pressure.

Therefore, we carefully inspected the internal structure of the autoclave.

Finally, we found that:

The bottom support plate inside the autoclave was not completely stable and had an uneven condition.

When only a small amount of weight was placed inside the autoclave, the issue was difficult to notice.

However, when the autoclave was fully loaded:

• The total weight increased;
• The bottom support area received higher pressure;
• The support plate slightly moved downward in certain areas.

As a result, some bottles located at the bottom experienced additional pressure, causing deformation around the bottle mouth.

After replacing the bottom support plate and repeating the test:

The deformation issue was no longer observed.

Why Is Systematic Investigation Important in Production?

In actual manufacturing environments, people often focus first on the most visible problem.

For example:

• Bottle deformation -> suspect the bottle quality;
• Cap issue -> suspect the cap design;
• Contamination -> suspect the culture vessel.

However, production problems often involve multiple connected factors.

Possible causes may include:

• The product itself;
• Sterilization equipment;
• Operating procedures;
• Loading methods;
• Supporting equipment.

Therefore, solving a production issue requires more than identifying the visible symptom.

A step-by-step elimination process is often necessary to locate the real cause.

Fulong Plastic’s Approach to Customer Support

As a manufacturer of plant tissue culture containers, Fulong Plastic focuses not only on supplying products.

More importantly, we aim to help customers build stable and efficient production systems.

When customers encounter application problems, we work through:

• On-site observation;
• Cause analysis;
• Practical testing;
• Process optimization;

to identify the real factors affecting production.

In many cases, solving a production issue is not only about fixing one problem, but also about helping customers improve their overall workflow.

Conclusion

PC tissue culture bottles used in commercial plant tissue culture production must withstand repeated autoclaving and long-term application conditions.

When unexpected issues occur, it is important not to immediately assign the cause to a single factor.

Through systematic investigation and practical verification, the real reason behind a problem can be identified.

For tissue culture container suppliers, product quality is important, but understanding customer production processes and supporting practical problem-solving are equally important parts of long-term cooperation.

About Fulong Plastic

Fulong Plastic has more than 20 years of experience in plant tissue culture container manufacturing.

We specialize in PC tissue culture bottles, PP culture containers, tissue culture tubes, wide-mouth culture cups, culture lids, breathable membranes, tissue culture bags, and culture baskets.

Our products are used by universities, research institutes, agricultural organizations, tissue culture laboratories, and commercial plant propagation companies.

We continue to share knowledge about plant tissue culture, micropropagation practices, and tissue culture container applications, and we hope to exchange experiences with professionals in the global tissue culture industry.