How to Read a Certificate of Analysis: A Guide for Food Ingredient Procurement

A Certificate of Analysis (COA) is the primary quality document in food ingredient trading. It reports the analytical test results for a specific batch of product, confirming that the ingredient meets agreed specifications. For procurement teams, reading a COA correctly means knowing which parameters matter for your ingredient category, recognising red flags that suggest an unreliable or fabricated document, and cross-referencing results against EU regulatory limits and your own purchase specifications.

In short:

• Every food ingredient COA should include: product identification (name, batch/lot number, production date), supplier details, test parameters with results and specifications, test methods, laboratory identification, and the date of analysis.
• Red flags on a COA include: results that exactly match specifications on every parameter, missing batch or lot numbers, untraceable laboratory details, outdated test methods, and results from the supplier’s own lab without third-party verification.
• Different ingredient categories require different COA parameters: oils need peroxide value and FFA; spices need essential oil content and aflatoxins; proteins need amino acid profiles; dried fruits need moisture and SO₂ levels.

Red Flags: What a Bad COA Looks Like

Experienced procurement professionals develop an eye for COAs that look “too perfect” or contain inconsistencies:

Every result exactly at the specification limit. Real analytical results show natural variation. If moisture is specified as “max 12%” and the COA reports “12.0%” on every batch, the results are likely fabricated or adjusted.

No batch/lot number or generic batch numbers. A COA without a traceable lot number is worthless for traceability purposes. Generic numbers like “2025/001” shared across multiple deliveries suggest the COA is being recycled.

In-house testing only with no third-party verification. Supplier self-testing creates an obvious conflict of interest. For high-risk ingredients, request independent laboratory analysis or split-sample testing.

Outdated or vague test methods. If the COA says “moisture: oven method” without specifying the ISO/AOAC method number, you cannot verify the testing protocol. Modern COAs should reference specific standardised methods.

Analysis date far from production date. A COA analysed months before or after the production date suggests the results may not represent the actual batch. Shelf-life-sensitive parameters (peroxide value, FFA, microbiological) change over time.

Missing or untraceable laboratory. If you cannot verify that the listed laboratory exists and holds ISO 17025 accreditation for the relevant tests, treat the COA with suspicion. Search the laboratory’s name in national accreditation body databases.

Essential COA Components Every Buyer Should Verify

• Product name and description: Including variety, grade, and form (e.g., “Organic pea protein isolate, 85% protein, spray-dried powder”). Vague descriptions are a red flag.
• Batch/lot number: The unique identifier that links this COA to a specific production batch. Without it, the COA cannot be traced to the physical product. This is non-negotiable.
• Production date and expiry/best-before date: Confirms freshness and shelf-life status. Check that the production date aligns with the expected crop season for raw materials.
• Test parameters and results: The analytical values for each tested attribute, presented alongside the specification limits (min/max). Results should include units and, where applicable, test precision.
• Test methods: The analytical methods used (e.g., “Moisture: Karl Fischer titration” or “Aflatoxin B1: HPLC per EN 12955”). Recognised methods (ISO, AOAC, EN) provide confidence in the results.
• Laboratory identification: Name and address of the testing laboratory. Ideally ISO 17025-accredited for the specific tests performed. In-house lab results should be supplemented by periodic third-party verification.
• Date of analysis and authorised signature: The analysis date should be close to the production date. A COA with a 2024 analysis date on a 2026 production batch is obviously wrong.

Category-Specific Parameters

Every ingredient category has parameters that matter beyond the standard microbiological and contaminant tests. Here's what to look for by category.

How to Cross-Check COA Data

A robust COA verification process includes these steps:

• Cross-reference against EU regulatory limits. Ensure all reported values comply with EU maximum levels (Regulation 1881/2006 for contaminants, MRL regulations for pesticides). The COA meeting the supplier’s internal spec is not sufficient if EU limits are stricter.
• Spot-check with your own or third-party testing. Periodically send retained samples to an independent ISO 17025 lab and compare results to the supplier’s COA. Significant discrepancies indicate a reliability problem.
• Verify laboratory accreditation. Check that the testing laboratory holds ISO 17025 accreditation from a recognised national body (e.g., UKAS, DAkkS, RvA) for the specific test methods listed on the COA.
• Request the full lab report, not just the summary COA. Many suppliers provide a simplified COA that omits details. The full laboratory report includes method details, measurement uncertainty, and analyst identification.
• Build a COA database and track trends. Over time, consistent suppliers will show natural variation within expected ranges. Sudden changes in a parameter’s pattern may indicate a change in sourcing, processing, or the accuracy of the reported data.

Common Questions

Can I trust a COA from the supplier’s own laboratory?

In-house COAs provide useful data but carry an inherent conflict of interest. For routine parameters on low-risk ingredients from trusted suppliers, in-house results are acceptable. For high-risk ingredients, food safety parameters (aflatoxins, Salmonella, pesticides), and new suppliers, always request or conduct independent third-party analysis.

What is ISO 17025 and why does it matter?

ISO 17025 is the international standard for testing and calibration laboratories. Accredited laboratories demonstrate competence in specific test methods, maintain quality management systems, and participate in proficiency testing. Results from ISO 17025-accredited labs carry legal weight and are accepted by regulators and auditors.

How long should I retain COAs?

Retain COAs for at least the shelf life of the ingredient plus one year, or as required by your GFSI standard (BRC requires minimum one year beyond shelf life). Digital archiving linked to batch/lot numbers enables rapid retrieval during audits or incidents.

What if the COA does not list a parameter I need?

If a COA is missing a parameter from your purchase specification, request the supplier to provide supplementary analysis before accepting the delivery. Common omissions include water activity (aw), specific allergen testing, and authenticity markers. Your purchase contract should specify which COA parameters are mandatory.

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