Introduction

After several days of strong winds and heavy rain caused by a typhoon, the storm finally passed. However, the prolonged rainfall and humid air created favorable conditions for certain microorganisms to remain, grow, and spread in dark and damp corners.

Vantsteri engineers were contacted by a pharmaceutical manufacturer after mold was detected in the cold storage area inside the cleanroom zone of its production workshop. The engineering team quickly arrived on site. At that time, the workshop had already stopped production, and facility personnel were manually applying disinfectants throughout the area.

Site Inspection

Vantsteri worked with the pharmaceutical manufacturer to establish a dedicated investigation team. The team included representatives from:

• Production department
• Quality control department
• Engineering department
• Vantsteri technical team

A comprehensive and detailed investigation was then carried out to identify the contamination source, assess the affected areas, and evaluate the effectiveness of the emergency response measures already taken.

The Mold Contamination Problem

The mold was first detected in the cold storage area inside the cleanroom. By the time the investigation began, the contamination issue had already continued for approximately two weeks.

During this period, the pharmaceutical facility had taken several emergency measures, including:

• Isolating potentially contaminated areas
• Spraying disinfectant into the air
• Wiping and disinfecting exposed surfaces
• Increasing disinfection frequency
• Monitoring microorganisms in both air and surface samples

However, despite the use of high-level disinfectants and more frequent cleaning procedures, the mold contamination did not decrease. Instead, the affected area gradually expanded, and the number of detected colonies continued to increase.

Samples of the detected mold were sent to a third-party genetic testing laboratory for identification. The result confirmed the contaminant as Penicillium.

What Is Penicillium?

Penicillium is a common fungal genus widely found in the natural environment. When it grows in large quantities, it often appears blue-green in color. Under microscopic observation, Penicillium structures may resemble small broom-like branches.

Penicillium spores are usually oval or cylindrical. Depending on the species, their surfaces may be smooth or rough.

This type of mold is commonly found on:

• Citrus fruits
• Vegetables
• Grains
• Meat products
• Leather
• Various food materials

Penicillium is a heterotrophic aerobic fungus. It can survive under relatively challenging environmental conditions and is known for its strong adaptability. Some Penicillium species can grow at lower temperatures, which makes cold storage areas a potential risk zone when moisture control is insufficient.

Organic acids commonly found in food and beverage environments, such as malic acid and citric acid, may also support the growth of certain mold species.

Why Mold Can Persist in Cleanroom Cold Storage Areas

Mold contamination in pharmaceutical cleanrooms can be difficult to eliminate because fungal spores are highly resistant to many environmental stresses. In cold storage areas, several factors may contribute to persistent contamination:

• High humidity after heavy rainfall or typhoon weather
• Condensation on surfaces
• Poor ventilation in corners or enclosed spaces
• Hidden contamination sources behind equipment or wall gaps
• Ineffective disinfectant contact time
• Incomplete surface coverage during manual disinfection
• Possible contamination of air ducts, drains, or insulation materials

In this case, the mold continued to spread despite repeated manual disinfection, indicating that the root contamination source had not yet been effectively identified or removed.

Root Cause Investigation and Contamination Control

Identifying the source of contamination is the most critical step in cleanroom mold remediation. Without locating and controlling the source, repeated disinfection may only provide temporary results.

Based on the biological characteristics of Penicillium and the contamination distribution observed on site, Vantsteri engineers analyzed potential contamination routes and high-risk areas.

The investigation focused on:

• Cold storage surfaces
• Airflow patterns
• Humidity and condensation-prone areas
• Hidden corners and gaps
• Equipment surfaces
• Air and surface microbial monitoring data
• Possible cross-contamination routes from personnel or materials

After the contamination source was identified, a targeted disinfection process and operational workflow were developed.

Disinfection Method and Implementation

Vantsteri developed a customized disinfection technical plan according to the on-site conditions and the biological properties of the contaminating mold.

The remediation process included:

• Isolation of affected areas
• Cleaning and removal of visible contamination risks
• Targeted treatment of high-risk surfaces
• Environmental disinfection of the cleanroom zone
• Strict control of operational procedures
• Verification of air and surface disinfection effectiveness

Disinfection engineers followed the approved workflow step by step to ensure that the treatment process was controlled, repeatable, and suitable for the cleanroom environment.

Results

After the targeted cleanroom mold remediation process, the mold contamination issue was successfully resolved.

The case demonstrated that effective cleanroom disinfection requires more than simply increasing disinfectant concentration or frequency. For persistent fungal contamination, especially in pharmaceutical cold storage areas, successful remediation depends on:

• Accurate identification of the contaminating microorganism
• Root cause investigation
• Analysis of environmental conditions
• Targeted disinfection workflow design
• Professional execution and post-treatment verification

Key Takeaways

Mold contamination in pharmaceutical cleanrooms can spread quickly when humidity and hidden contamination sources are not properly controlled.

This case highlights the importance of:

• Routine environmental monitoring
• Moisture and condensation control
• Early investigation of abnormal microbial results
• Proper identification of fungal contaminants
• Targeted cleanroom disinfection instead of repeated general spraying
• Professional contamination source analysis

By combining microbial identification, source investigation, and customized disinfection procedures, pharmaceutical cleanroom mold contamination can be effectively controlled and prevented from recurring.

Conclusion

Penicillium contamination in cleanroom cold storage areas can pose a serious risk to pharmaceutical production environments. In this case, Vantsteri engineers worked with the manufacturer’s production, quality, and engineering teams to identify the source of contamination and implement a targeted cleanroom disinfection solution.

Through systematic investigation and professional remediation, the facility successfully resolved the mold contamination event and restored environmental control within the affected cleanroom area.