GMP Audit Preparation Guide

"The most common thing I hear from dietary supplement quality managers before an audit is: 'We think we're compliant, but we're not sure.'"

That uncertainty is expensive. An FDA investigator who catches you unprepared will find violations that a prepared facility could have avoided. Preparation means building the documented, practiced quality system that the regulations require — and making sure your team can demonstrate it to anyone who walks through the door.

Part 1: Understanding What Auditors Look For

FDA Inspections

FDA operates under a risk-based framework — looking for systematic failures, not every minor deviation.

FDA's Top Inspection Priorities:

1. Identity testing of incoming ingredients
2. Finished product specifications and testing
3. CAPA system effectiveness
4. Record integrity (contemporaneous, accurate, complete)
5. Personnel training evidence
6. Building and equipment maintenance

• Typically unannounced for domestic manufacturers

• Duration: 1–5 days for small facilities

• Observations recorded on FDA Form 483

Third-Party Audits (NSF 455-2, USP, UL/GMP)

Scheduled in advance with published criteria — you can prepare precisely.

Key Differences from FDA:

• Audit criteria are published — prepare precisely
• More process-focused than risk-focused
• Non-conformances classified as Major or Minor
• Major non-conformance must be corrected before certification

Why certification matters:

• Walmart, Costco, Amazon increasingly require NSF or USP

• Signals compliance maturity to customers/partners

Month 1

Weeks 1–4

Assess and Organize

Week 1 Document Inventory

Pull every quality document you have and assess its status:

Document Category	Current?	Approved?	Accessible?
Quality Policy
Master Manufacturing Records
Batch Production Records (past 2 years)
Component Specifications
Finished Product Specifications
SOPs (Receiving, Production, QC, etc.)
Training Records
Equipment Calibration Records
CAPA Records
Supplier Qualification Files

Week 2 Gap Assessment

Using the 21 CFR Part 111 Compliance Checklist, conduct a formal self-assessment. Create a gap log:

Gap	Regulation	Risk
e.g. No identity testing for Ingredient X	§111.75	High

Week 3 Conduct Mock Interviews

For QA/QC Staff:

• What do you do when a batch fails a specification?
• How do you verify incoming ingredients meet your standards?
• Walk me through an OOS investigation
• What happens when a customer files a complaint?

For Production Staff:

• What do you do if you notice a problem during manufacturing?
• How do you know which procedure to follow?
• What do you do if you make an error in the batch record?

For Management:

• How do you know your quality system is working?
• When did you last conduct a management review?
• What has your CAPA system identified as a systemic issue?

Week 4 Facility Walk-Through Checklist

SOPs are posted or accessible at points of use
Cleaning equipment is stored properly and labeled
Equipment maintenance logs are current and near the equipment
Raw materials are properly labeled, quarantined, and segregated
Reject/quarantine areas are physically separated and clearly labeled
No visible contamination risk (exposed product near open drains, overhead pipes)
Temperature monitoring devices are calibrated and logs are current
Facility is in good repair (no peeling paint, damaged flooring, holes in walls)

Month 2

Weeks 5–8

Close Gaps and Train

Weeks 5–6 Close High-Priority Gaps

Identity Testing Gaps:

• Establish a written identity testing procedure
• Validate or verify test methods
• Test all lots currently in inventory lacking documentation
• Contract with accredited lab if needed

Missing Specifications:

• Write specifications for every component and finished product
• Include: identity, purity, strength, composition, contaminant limits
• Get specifications approved and dated by QC

CAPA Gaps:

• Implement CAPA system now — even a spreadsheet works if used consistently
• Write the CAPA SOP
• Open CAPAs for any known quality issues

Week 7 Update Training Records

Ensure every quality and production employee has documented training on your SOPs.

Training records must include: name, date, SOP or topic, trainer signature, and employee signature.

⚠ Never backfill or falsify training dates. This is a federal violation and will be discovered during inspection.

Week 8 Organize Your Records Room

During an inspection, if you can't find a record, an investigator may conclude it doesn't exist. Records should be retrievable in minutes, not hours.

• Batch Production Records: by lot number and product

• Lab records: by test and date

• CAPA files: organized and numbered

• Complaint files: organized and indexed

Month 3

Weeks 9–12

Practice and Finalize

Week 9 Conduct a Full Mock Inspection

Have someone unfamiliar with your day-to-day operations conduct a formal mock inspection: walk the facility as an investigator would, request records in the way FDA would, interview key personnel. Score the mock inspection and close any remaining findings before the real inspection.

Week 10 Train Your Escort Team

Primary Escort (QA Director)

With investigator at all times. Answers regulatory questions.

Records Coordinator

Retrieves requested records quickly. Pre-organizes binders.

Technical Expert

Production/lab manager available for technical questions.

Escort team rules: You must provide requested records. Answer questions directly and honestly — do not volunteer additional information. If you don't know an answer, say so and offer to find out. Take notes on every document the investigator reviews.

Week 12 Final Check Before Audit Day

All high-priority gaps from Month 1 are closed and documented
Training records are current for all employees
Equipment calibration and maintenance logs are current
Batch records for the past 2 years are organized and accessible
CAPA files are organized and current
Escort team and records team are briefed and ready
Management is prepared and briefed on known risks

Inspection Day: Quick Reference

Document	Location	Person Responsible
Batch Production Records (past 2 years)	Records Room / Binder	QA Admin
Master Manufacturing Records	QA Office	QA Manager
Component Specifications	QA Office / LIMS	QA Manager
Lab Test Records	Lab / LIMS	Lab Manager
Equipment Calibration Log	Maintenance Office	Maintenance Lead
CAPA Files	QA Office	QA Manager
Training Records	HR / QA Office	HR / QA
Supplier Qualification Files	QA Office	Procurement / QA
Distribution Records	Shipping / ERP	Operations

NSF 455-2 Specific Preparation

Documents Required for NSF Document Review

• Quality manual or quality policy
• All SOPs referenced in your quality system
• Master Manufacturing Records for each product to be certified
• Sample Batch Production Records
• Lab records and method validations
• CAPA records and corrective action trends
• Supplier qualification files
• Training program and records

Questions NSF Auditors Commonly Ask

• "Show me how you would handle this hypothetical situation" (tests practical application)
• "What was the root cause of the last CAPA you opened?"
• "What trends has your CAPA system identified in the past year?"
• "Walk me through your supplier qualification process for a new ingredient supplier"
• "How do you know your test methods are reliable?"

Jared Clark, CPGP, PMP, CMQ-OE | Certify Consulting Group | thegmpconsultant.com | 858-240-4353

This guide is for educational purposes only and does not constitute regulatory or legal advice. FDA inspection procedures and third-party audit criteria are subject to change. Consult current FDA guidance and NSF, USP, or UL audit criteria for the most current requirements. © 2026 Certify Consulting Group.