How to read an olive oil COA line by line

Q: What is a COA and what is it for?

Short answer: a COA (Certificate of Analysis) is the document that proves the category of a batch of olive oil. It gathers the results measured in the laboratory — acidity, peroxide, UV absorbances, ethyl esters, sometimes polyphenols and sensory panel — and compares them to the regulatory thresholds. It only has value for export if it co

Q: What is an olive oil COA?

A certificate of analysis that proves a batch's category by gathering the results measured in the laboratory (acidity, peroxide, K232/K270/ΔK, FAEE, sometimes polyphenols and panel) and comparing them to the IOC/EU thresholds. It only has value for export if it comes from an IOC-recognized laboratory .

Q: How do you know if a COA is valid?

Check that the header mentions an IOC-recognized laboratory with its accreditation, that the batch number matches your order, and that the sampling date is recent. A COA without an identifiable lab, without a batch, or undated is worthless.

Q: Which lines should you check first on a COA?

The free acidity (≤ 0.80% for extra virgin), the peroxide value (≤ 20), the UV absorbances (K232 ≤ 2.50, K270 ≤ 0.22, ΔK ≤ 0.01) and, for official grading, the sensory panel (Md = 0, Mf 0). Then the purity parameters (FAEE, stigmastadienes, waxes).

Q: What does a ΔK above the threshold mean?

A ΔK (Delta-K) 0.01 signals probable blending with refined oil. It is a major anti-fraud parameter. An exceedance should halt the order until the batch's origin is clarified.

Q: Does the COA always show polyphenols?

No. Polyphenols are an optional line: they do not serve to classify the oil into categories, but to claim the EFSA health claim if the level reaches ≥ 250 mg/kg . Ask for it explicitly if that argument matters to you. See the polyphenols & EFSA guide.

Q: Is a chemical COA enough to prove extra virgin?

No. Official grading also requires sensory analysis. The panel must confirm a zero defect median (Md = 0) and positive fruitiness (Mf 0). An oil that is chemically compliant but shows a defect is downgraded to virgin.

Q: What are stigmastadienes and waxes on a COA?

Authenticity parameters . Stigmastadienes (≤ 0.05 mg/kg) betray the presence of refined oil; waxes (≤ 150 mg/kg for C42+44+46) betray pomace oil. An exceedance reveals fraud by blending.

You receive a COA (certificate of analysis) before ordering a batch of olive oil, but the lines look obscure — acidity, K232, ΔK, FAEE, Md, Mf? This guide decodes each line of a certificate of analysis: what it corresponds to, its exact IOC/EU threshold, and what exceeding it means in practice. You'll be able to confirm for yourself that the declared category is proven — and spot a misleading COA. Reading table, step-by-step method, pitfalls, and FAQ included.

Free PDF grid: every line of a COA, its threshold, and what an exceedance reveals, on one page. Get it by email »

What is a COA and what is it for?

Short answer: a COA (Certificate of Analysis) is the document that proves the category of a batch of olive oil. It gathers the results measured in the laboratory — acidity, peroxide, UV absorbances, ethyl esters, sometimes polyphenols and sensory panel — and compares them to the regulatory thresholds. It only has value for export if it comes from an IOC-recognized laboratory. In Tunisia, per-batch analysis goes through the ONH.

Without a COA, the label "extra virgin" is merely a commercial claim. With a COA from a recognized lab, it becomes verifiable data, per batch. It is your first line of defense against category error and fraud. The technical terms used here are defined in the glossary and detailed in the quality & standards guide.

The anatomy of a COA: the blocks to spot

A serious certificate of analysis has three zones. Read them in order.

Block	What it contains	What you check
Header	Laboratory, accreditation, batch no., sampling date, sample reference	Is the lab IOC-recognized? Does the batch match your order?
Body — quality	Acidity, peroxide, K232, K270, ΔK	Does the declared category hold up?
Body — purity & sensory	FAEE, stigmastadienes, waxes, panel (Md, Mf)	Authenticity and official grading confirmed?

First reflex: if the header mentions no identifiable laboratory or no accreditation, the COA is worthless — however beautiful the figures. A COA that is undated or whose batch number does not match your order is also a warning sign.

The body of the COA: line-by-line decoding

Here is each line you will encounter, its unit, its threshold for extra virgin, and the interpretation of an exceedance.

COA line	Unit	Extra virgin threshold	An exceedance means…
Free acidity	% oleic acid	≤ 0.80%	Degraded olives / late milling → downgrade to virgin (≤ 2.0%)
Peroxide value	mEq O₂/kg	≤ 20	Primary oxidation: tired, poorly stored, or old oil
K232	absorbance	≤ 2.50	Oxidation; EU-required
K270	absorbance	≤ 0.22	Secondary oxidation or trace of refined oil
ΔK (Delta-K)	absorbance	≤ 0.01	Probable blending with refined oil
Ethyl esters (FAEE)	mg/kg	≤ 35	Olive fermentation, poor raw material
Stigmastadienes	mg/kg	≤ 0.05	Presence of refined oil (fraud)
Waxes (C42+44+46)	mg/kg	≤ 150	Presence of pomace oil (fraud)
Polyphenols	mg/kg	— (≥ 250 for the EFSA claim)	Below 250, no health claim possible
Panel — Md (defects)	median	= 0	Sensory defect → downgrade to virgin or lampante
Panel — Mf (fruitiness)	median	> 0	No fruitiness → not compliant with extra virgin

For virgin (not extra), acidity rises to ≤ 2.0% and the defect median to ≤ 3.5. Peroxide and UV remain identical.

Enter your COA values into the quality classifier: it instantly tells you the batch's true category.

Key point: a COA is read by cross-checking all the lines against the declared category. A single line out of range can downgrade the oil, even if all the others are excellent.

Polyphenols and the EFSA claim on the COA

Some COAs show a polyphenols line (or "total phenolic compounds"). It does not enter into category classification, but it is decisive for valorization: above 250 mg/kg of hydroxytyrosol and derivatives, the oil can carry the health claim authorized by EU Regulation 432/2012. Below that, the claim is forbidden.

It is a major selling point for oils with a pungent profile (like Tunisian Chetoui, often above the threshold). Details and conditions of use in the polyphenols & EFSA guide.

Sidebar: buyer side / seller side

The same COA reads both ways.

Angle	What reading a COA changes for you	Reflex
Buyer (importer)	You validate the category yourself, without taking the seller's word for it	Require a COA per batch, IOC-recognized lab, and compare each line to the threshold
Seller (exporter who sells)	A clear, complete COA shortens the decision cycle	Provide a readable, dated, per-batch COA covering all criteria
Exporter (Tunisia operations)	A COA in the right format avoids customs blockages	Make sure the format matches the requirements of the destination market

Seller / exporter side

A credible exporter attaches the COA before it is asked for, from the right recognized laboratory, in the right format for the target market. See the quality process.

How to read a COA step by step

Check the header: IOC-recognized laboratory, accreditation, batch no. matching your order, sampling date.
Check the free acidity: ≤ 0.80% (extra) or ≤ 2.0% (virgin) depending on the declared category.
Check oxidation: peroxide ≤ 20, K232 ≤ 2.50, K270 ≤ 0.22, ΔK ≤ 0.01.
Check purity and freshness: FAEE ≤ 35, stigmastadienes ≤ 0.05, waxes ≤ 150.
Read the sensory panel: Md = 0 and Mf > 0 for an extra virgin.
Cross-check against the declared category: each line must be compatible; otherwise, the oil is downgraded.

Mistakes to avoid when reading a COA

Looking only at acidity: it is not enough to prove extra virgin; peroxide, UV, FAEE, and panel count just as much.
Ignoring the header: a COA without an identifiable IOC-recognized laboratory has no value.
Not checking the batch number: a beautiful COA that corresponds to another batch proves nothing for your order.
Confusing polyphenols and category: polyphenols do not classify the oil; they condition the health claim.
Forgetting the panel: a purely chemical COA is not enough to validate an official extra virgin.
Neglecting the date: an old COA may no longer reflect the current state of a poorly stored batch.

Golden rules

Header first: IOC-recognized laboratory, matching batch no., recent date.
Cross-check all the lines against the declared category, not just acidity.
Extra virgin thresholds: acidity ≤ 0.80%, peroxide ≤ 20, K232 ≤ 2.50, K270 ≤ 0.22, ΔK ≤ 0.01, FAEE ≤ 35.
Panel: Md = 0 and Mf > 0 for an official extra virgin.
One line out of range downgrades the batch, even if everything else is perfect.

Quality classifier » to interpret your COA, then document checklist » for the rest of the file.

FAQ — Reading an olive oil COA

What is an olive oil COA?

A certificate of analysis that proves a batch's category by gathering the results measured in the laboratory (acidity, peroxide, K232/K270/ΔK, FAEE, sometimes polyphenols and panel) and comparing them to the IOC/EU thresholds. It only has value for export if it comes from an IOC-recognized laboratory.

How do you know if a COA is valid?

Check that the header mentions an IOC-recognized laboratory with its accreditation, that the batch number matches your order, and that the sampling date is recent. A COA without an identifiable lab, without a batch, or undated is worthless.

Which lines should you check first on a COA?

The free acidity (≤ 0.80% for extra virgin), the peroxide value (≤ 20), the UV absorbances (K232 ≤ 2.50, K270 ≤ 0.22, ΔK ≤ 0.01) and, for official grading, the sensory panel (Md = 0, Mf > 0). Then the purity parameters (FAEE, stigmastadienes, waxes).

What does an acidity of 1.2% on a COA mean?

It exceeds the extra virgin threshold (≤ 0.80%) but stays below the virgin one (≤ 2.0%). The batch therefore cannot be sold as extra virgin: at best it is a virgin. Always cross-check acidity against the declared category.

What does a ΔK above the threshold mean?

A ΔK (Delta-K) > 0.01 signals probable blending with refined oil. It is a major anti-fraud parameter. An exceedance should halt the order until the batch's origin is clarified.

Does the COA always show polyphenols?

No. Polyphenols are an optional line: they do not serve to classify the oil into categories, but to claim the EFSA health claim if the level reaches ≥ 250 mg/kg. Ask for it explicitly if that argument matters to you. See the polyphenols & EFSA guide.

Is a chemical COA enough to prove extra virgin?

No. Official grading also requires sensory analysis. The panel must confirm a zero defect median (Md = 0) and positive fruitiness (Mf > 0). An oil that is chemically compliant but shows a defect is downgraded to virgin.

What are stigmastadienes and waxes on a COA?

Authenticity parameters. Stigmastadienes (≤ 0.05 mg/kg) betray the presence of refined oil; waxes (≤ 150 mg/kg for C42+44+46) betray pomace oil. An exceedance reveals fraud by blending.

Must the COA be issued per batch?

Yes. Every batch of oil is different; a COA only proves the quality of the analyzed batch. Check that the COA's batch number matches your order's exactly. A "generic" COA without a batch has no probative value.

What should you do if a line exceeds the threshold?

A single line out of range downgrades the batch or signals fraud, even if the others are excellent. Depending on the line concerned: category downgrade (acidity, peroxide), suspicion of blending (K270, ΔK, stigmastadienes), or sensory defect (Md). Ask for explanations before any deposit.

Does a COA replace a reference sample?

No, it complements it. The COA proves the measured values; the sealed, dated reference sample lets you physically compare the delivered batch. Together they form your protection in case of dispute. See the guide on choosing a reliable supplier.

Where can I have a COA I receive checked?

Enter its values into the quality classifier to place the category, and turn to an IOC-recognized laboratory if you want an independent counter-analysis on a sample taken at delivery.

Validate every batch with confidence

You now know how to read a COA line by line, spot a misleading certificate, and confirm a batch's category yourself. The next step: apply this reading to a real COA and secure your file.

Quality classifier » then document checklist ».

Request a free quote — dated quotation with a sample COA from an IOC-recognized laboratory, from an approved exporter, for your market. Drawer pre-filled with "Reading a COA Guide".

Free PDF grid (lead magnet): receive by email the "Reading an olive oil COA" grid — every line of the certificate, its IOC/EU threshold, and what an exceedance means, ready to tick against a COA you receive. Simple sign-up (Brevo double opt-in), no spam. Receive the PDF grid »

To go further, read the IOC/EU quality & standards guide, the polyphenols & EFSA guide, the guide on choosing a reliable supplier, and the bulk extra virgin page.

Data July 2026, indicative and to be re-verified before any commitment. Sources: IOC trade standard COI/T.15/NC Rev. 20-21, EU Regulation 2022/2104 (analysis methods), EU Regulation 432/2012 (polyphenols), IOC-recognized laboratories, ONH export approval (Tunisia).