SOP for Cleaning of Deep Freezer
Standard Operating Procedure (SOP) for Cleaning of Deep Freezer
1.0 Purpose
To define the procedure for cleaning and maintaining the deep freezer to ensure proper functioning, prevent contamination, and maintain sample integrity.
2.0 Scope
This SOP applies to all deep freezers used for storage of microbial cultures, reagents, and temperature-sensitive materials in the Quality Control and Microbiology Laboratory.
3.0 Responsibility
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Analyst/Operator: To clean and record cleaning activities.
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QC/Microbiology Head: To review and verify records.
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Engineering/Maintenance: For servicing and preventive maintenance.
4.0 Definitions
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Deep Freezer: A low-temperature storage unit (-20°C or -80°C) used for long-term preservation of materials.
5.0 Procedure
5.1 Pre-Cleaning Checks
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Ensure all samples/materials are removed and temporarily stored in another qualified freezer (if required).
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Switch OFF the power supply and disconnect the unit.
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Allow the freezer to reach room temperature (defrost if ice is accumulated).
5.2 Cleaning Process
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Wear appropriate PPE (lab coat, gloves, mask, goggles).
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Remove detachable racks, trays, and shelves. Clean separately with mild detergent solution and rinse with distilled water.
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Wipe the internal surfaces with 70% Isopropyl Alcohol (IPA) or other approved disinfectant.
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For stubborn stains/ice:
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Use a plastic scraper (never metal) to remove ice build-up.
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Wipe surfaces dry with a clean, lint-free cloth.
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Clean the external surface with lint-free cloth and mild detergent followed by 70% IPA.
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Ensure no disinfectant residue is left inside.
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Refix trays/shelves after drying completely.
5.3 Post-Cleaning
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Switch ON the power supply.
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Allow freezer to stabilize to the set operating temperature (-20°C / -80°C).
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Place samples back into the freezer once the required temperature is achieved.
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Record cleaning details in the Deep Freezer Logbook (date, time, cleaned by, verified by).
6.0 Frequency
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Routine Cleaning: Once a month.
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Defrosting & Deep Cleaning: Once every 3 months or as required.
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Immediate Cleaning: In case of spillage, contamination, or breakdown.
7.0 Precautions
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Do not use sharp or metallic objects to remove ice (risk of damaging coils).
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Never use flammable cleaning agents.
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Avoid prolonged power OFF conditions when samples are inside.
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Ensure proper temperature is restored before sample reloading.
8.0 Documentation
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Record cleaning details in the Equipment Cleaning Logbook.
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Maintain records for audit and compliance.
9.0 References
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Manufacturer’s Manual
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Laboratory QA/QC Procedures
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WHO Laboratory Biosafety Guidelines
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