Beyond Sterilization: Validating the Hold Time of Sterile Garments

In highly controlled pharmaceutical environments, such as aseptic filling and sterility testing areas, the sterility of garments worn by personnel is a critical control measure. While sterilization processes effectively eliminate microbial life, the garments must maintain that sterility until they are used. This assurance is provided through a dedicated Hold Time Validation Study.

The primary objective is to scientifically confirm the maximum safe period—the Hold Time—for sterilized garments after processing, ensuring they remain free of microbial contamination while awaiting use.

🎯 Objective and Scope of the Hold Time Study

Objective: To provide documented evidence that sterilized garments retain their sterile status for a period up to 5 days (120 hours) after sterilization, when stored under defined conditions, by using a microbial detection method.

Scope: This protocol evaluates the microbial presence on sterilized garments over time to establish a validated hold time after sterilization, using an established microbiological method (Sterility Test).

Purpose of Study: To establish the rate of microbial proliferation (or lack thereof) in the sterilized garments during the specified holding period.

👥 Responsibility and Accountability

The integrity of this study relies on clear departmental roles:

Quality Control (QC) Microbiology: Responsible for the preparation, review, and execution of the protocol, including all sampling and testing.
Quality Assurance (QA): Responsible for the review and final approval of the protocol and the final validation report.

🧪 Procedure: Simulating Real-World Storage

The hold time study is designed to simulate the actual storage conditions and challenge the garment's ability to remain sterile.

1. Pre-Requisite and Preparation

Environmental Conditions: Ensure the environmental conditions of the storage area (the Garment Cubicle) are maintained within established limits (e.g., cleanliness, temperature, humidity).
Sample Preparation: Prepare a Dacron bag containing one pair of sterility testing area garments. To mimic areas of higher contamination risk and provide a sufficient sample size, 10 cut pieces ( $6 \times 5\text{ cm}$ ) of old garment material are placed within the main garment (or between the layers).
Sterilization: The prepared bag is sterilized according to the facility's standard SOP for sterilization of dresses.

2. Hold Time Sampling and Testing

The clock for the 0 Hour mark begins when the sterilized Dacron bag is placed into the designated Garment Cubicle after sterilization.

Sampling Method: Aseptically collect one cut piece of the dress material from the bag at each time point.
Initial Sample (0 Hour): The first cut piece is collected immediately upon placement in the cubicle and tested.
Interval Sampling: Subsequent pieces are collected at regular intervals: $24\text{ hr}, 48\text{ hr}, 72\text{ hr}, 96\text{ hr},$ and $120\text{ hr}$ .

3. Sterility Test and Incubation

Testing: Each collected cut piece is immediately and directly immersed into a suitable sterile growth medium, such as Soybean Casein Digest Medium (SCD medium), to perform a qualitative Sterility Test.
Incubation: The media samples are incubated for a total of 14 days under dual temperature conditions to support the growth of a broad spectrum of microorganisms:

$20-25^\circ \text{C}$ for 7 days (for fungi and room-temperature bacteria).
$30-35^\circ \text{C}$ for 7 days (for mesophilic bacteria).

📈 Acceptance Criteria and Conclusion

Acceptance Criteria

The study is successful only if the sterility is maintained across the entire study period:

Microbial Determination: No growth should be observed in the sterility test for the samples collected at $0, 24, 48, 72, 96,$ and $120\text{ hours}$ .

Conclusion

A final Hold Time Study Summary Report is prepared after all data is evaluated (i.e., after the 14-day incubation period for the final $120\text{ hr}$ sample). The report's conclusion definitively states the established, validated hold time period for sterilized garments (e.g., $120\text{ hours}$ or 5 days).

This validated hold time ensures that when critical personnel don the sterile garments, the integrity of the controlled environment is never compromised by microbial contamination from the attire itself .