Quality control from mill to container: harvest

Q: How is the quality of an olive oil controlled, from the mill to the container?

The quality of an extra virgin olive oil is built at the mill and proven at the laboratory . It follows a continuous chain: harvest at the right stage , cold extraction (< 27 °C) within a short time, physicochemical and sensory analyses according to IOC methods , sampling of a sealed reference sample , then issuance of a COA (certificate

Q: How is the quality of an olive oil controlled before export?

Through a continuous chain: harvest at the right stage, cold extraction < 27 °C within a short time, IOC analyses (acidity, peroxide, K232/K270/ΔK, sensory panel), sampling of a sealed sample and issuance of a COA per lot by an IOC-approved laboratory. Every link conditions the final classification.

Q: What does "cold extraction" exactly mean?

It means extraction by mechanical processes only , with malaxation below 27 °C . Above this temperature, yield increases but aromas and polyphenols degrade. The claim is regulated and assumes compliance with this threshold.

Q: Which thresholds must an oil respect to be extra virgin?

Acidity ≤ 0.80% , peroxide ≤ 20 mEq O₂/kg , K232 ≤ 2.50 , K270 ≤ 0.22 , ΔK ≤ 0.01 , ethyl esters ≤ 35 mg/kg , with a sensory panel of zero defect median and positive fruitiness. Both chemistry and sensory analysis must be met.

Q: Why is the sensory panel mandatory?

Because the official IOC classification rests on chemistry and tasting. An oil chemically compliant but presenting a sensory defect (rancid, musty, fusty) is downgraded . Only an approved panel can establish the median of defects and fruitiness.

Q: Can you improve a medium-quality oil in the laboratory?

No. Quality is built at the mill and cannot be corrected after extraction. The laboratory classifies and proves quality, it does not repair it. A lot poorly harvested or milled too late will be classified virgin or lampante, with no possible return to extra virgin.

Q: What is the sealed reference sample?

It is a representative sample of the lot, taken and sealed before shipment, kept by the seller and handed to the buyer. In the event of a dispute on arrival, it serves as neutral proof compared to the COA and the goods. It is a standard securing practice.

Q: Who can issue a COA valid for export?

Only an IOC-approved laboratory ; in Tunisia, issuance runs through the National Oil Office (ONH) . The COA is established per lot , never globally, and documents the physicochemical and sensory parameters of the lot shipped.

Q: Why does the delay between harvest and milling matter?

Because olives waiting in heaps ferment and see their acidity and defects increase. The faster milling follows harvest, the lower the acidity remains and the more the fruitiness is preserved. It is a key factor in the extra virgin classification.

Q: How is quality preserved up to the container?

Through storage protected from air, light and heat in inert tanks, oxidation being the main enemy between the mill and shipment. The filling of the flexitank, IBCs or drums only takes place after validation of the COA .

Available certifications

EcocertUSDA OrganicUE BioHalalKosherIFS / BRC

How is the quality of an olive oil controlled, from the mill to the container?

The quality of an extra virgin olive oil is built at the mill and proven at the laboratory. It follows a continuous chain: harvest at the right stage, cold extraction (< 27 °C) within a short time, physicochemical and sensory analyses according to IOC methods, sampling of a sealed reference sample, then issuance of a COA (certificate of analysis) per lot by an IOC-approved laboratory. Every link counts: an oil cannot be "rescued" in the laboratory, only classified.

This page describes the quality journey that each lot follows before leaving in a container. The thresholds cited are those of the IOC/T.15/NC standard and EU regulations (2022/2104). All figures are dated *July 2026 — to be verified *. To interpret a bulletin, use the COA quality classifier.

The quality chain in brief

Harvest at the right stage of ripeness, healthy olives, without injury or fermentation.
⏱ Fast milling after picking to limit acidity and defects.
Cold extraction (< 27 °C) — condition of the "cold extraction" claim.
IOC analyses: acidity, peroxide, K232/K270/ΔK, sensory panel, polyphenols.
Sealed reference sample kept on both sides.
COA per lot issued by an IOC-approved laboratory (via the ONH).

Principle: quality cannot be corrected after extraction. A lot poorly harvested or milled too late will be correctly classified (virgin, lampante) but will not become extra virgin again. Control serves to guarantee and prove, not to repair.

Step 1 — Harvest at the right stage

Quality begins at the grove. Healthy olives, harvested at the optimal stage of ripeness (veraison, depending on the variety and desired profile), without injury or prolonged contact with the ground, are the condition for low acidity. The Tunisian varieties — Chemlali (mild, fruity, South/Sfax) and Chetoui (fiery, rich in polyphenols, North) — give distinct profiles that harvest preserves or degrades.

The harvest → milling delay is decisive: the shorter it is, the more acidity and fermentation defects are controlled. Olives must not wait in heaps.

Step 2 — Cold extraction (< 27 °C)

Extra virgin oil is obtained by mechanical processes only (no solvent, no excessive heat). The "cold extraction" or "cold first pressing" claim assumes a malaxation temperature below 27 °C. Above that, yield rises but aromas and polyphenols degrade.

After extraction come filtration (usual loss ~1.8%) and storage in inert tanks, protected from air, light and heat — oxidation is the main enemy between the mill and the container.

Step 3 — Analyses according to IOC methods

Each lot is analysed by an IOC-approved laboratory. The extra virgin parameters and thresholds:

Analysis	Extra virgin threshold	What it measures
Free acidity	≤ 0.80%	Enzymatic degradation of the fruits
Peroxide value	≤ 20 mEq O₂/kg	Primary oxidation (freshness)
K232	≤ 2.50	Oxidation (UV absorbance, required EU)
K270	≤ 0.22	Oxidation / trace of refined oil
ΔK (Delta-K)	≤ 0.01	Detection of refining
Ethyl esters (FAEE)	≤ 35 mg/kg	Fermentation of the olives
IOC sensory panel	Md = 0, Mf > 0	Zero defects, positive fruitiness
Polyphenols (EFSA option)	≥ 250 mg/kg	Eligibility for EU health claim 432/2012

The official classification (extra virgin, virgin, lampante) requires an approved sensory panel in addition to the chemistry. An oil chemically compliant but presenting a sensory defect (rancid, musty, fusty) is downgraded. Chemistry and tasting are authoritative.

Step 4 — Sealed reference sample

Before shipment, a representative sample of the lot is taken and sealed, kept by the seller and handed to the buyer. It constitutes the neutral proof in the event of a quality dispute on arrival: it is compared to the COA and the goods delivered. It is a simple and standard protection, never to be neglected on a first business flow.

Step 5 — COA per lot and container departure

The COA (certificate of analysis) summarises the lot's results. Valid for export only if it comes from an IOC-approved laboratory (ONH obligation in Tunisia), it is issued per lot and accompanies the goods with the other certificates (origin, sanitary, TRACES if organic). Bulk packaging — flexitank ~22,000 L, IBC 1,000 L or drums 200 L — is filled after validation of the COA.

This COA links to the certificates per lot and per market page, which details the complete documentary set.

The organic thread in the quality chain

For an organic lot, the quality chain incorporates an additional requirement: flow separation organic / conventional at the mill, in storage and in packaging, traced and audited by the certification body (Ecocert, present in Sfax). The COA then also documents the absence of synthetic residues (usual investigation threshold 0.01 mg/kg). Organic combines well with the high polyphenols of Chetoui for a dual premium + health argument. See organic & Ecocert.

Buyer side / seller side

Buyer side (importer, brand)	Seller side (exporter)
Ask for the COA per lot (IOC-approved lab), the sealed reference sample and, if relevant, proof of cold extraction and the polyphenol level. Compare the sample to the delivery.	Master the chain harvest → extraction < 27 °C → analyses → COA, take a sealed sample, store protected from oxidation and trace organic separation if applicable.
CTA: request a quote	CTA: train in export

FAQ — Quality control from mill to container

How is the quality of an olive oil controlled before export?

Through a continuous chain: harvest at the right stage, cold extraction < 27 °C within a short time, IOC analyses (acidity, peroxide, K232/K270/ΔK, sensory panel), sampling of a sealed sample and issuance of a COA per lot by an IOC-approved laboratory. Every link conditions the final classification.

What does "cold extraction" exactly mean?

It means extraction by mechanical processes only, with malaxation below 27 °C. Above this temperature, yield increases but aromas and polyphenols degrade. The claim is regulated and assumes compliance with this threshold.

Which thresholds must an oil respect to be extra virgin?

Acidity ≤ 0.80%, peroxide ≤ 20 mEq O₂/kg, K232 ≤ 2.50, K270 ≤ 0.22, ΔK ≤ 0.01, ethyl esters ≤ 35 mg/kg, with a sensory panel of zero defect median and positive fruitiness. Both chemistry and sensory analysis must be met.

Why is the sensory panel mandatory?

Because the official IOC classification rests on chemistry and tasting. An oil chemically compliant but presenting a sensory defect (rancid, musty, fusty) is downgraded. Only an approved panel can establish the median of defects and fruitiness.

Can you improve a medium-quality oil in the laboratory?

No. Quality is built at the mill and cannot be corrected after extraction. The laboratory classifies and proves quality, it does not repair it. A lot poorly harvested or milled too late will be classified virgin or lampante, with no possible return to extra virgin.

What is the sealed reference sample?

It is a representative sample of the lot, taken and sealed before shipment, kept by the seller and handed to the buyer. In the event of a dispute on arrival, it serves as neutral proof compared to the COA and the goods. It is a standard securing practice.

Who can issue a COA valid for export?

Only an IOC-approved laboratory; in Tunisia, issuance runs through the National Oil Office (ONH). The COA is established per lot, never globally, and documents the physicochemical and sensory parameters of the lot shipped.

Why does the delay between harvest and milling matter?

Because olives waiting in heaps ferment and see their acidity and defects increase. The faster milling follows harvest, the lower the acidity remains and the more the fruitiness is preserved. It is a key factor in the extra virgin classification.

How is quality preserved up to the container?

Through storage protected from air, light and heat in inert tanks, oxidation being the main enemy between the mill and shipment. The filling of the flexitank, IBCs or drums only takes place after validation of the COA.

What does quality control change for an organic lot?

It adds the traced separation of flows organic / conventional at the mill, in storage and in packaging, audited by the certification body (Ecocert). The COA also documents the absence of synthetic residues (usual threshold 0.01 mg/kg). See organic & Ecocert.

Are polyphenols measured in quality control?

They can be, as an option. If the level exceeds 250 mg/kg (frequent with Chetoui), the lot is eligible for the EFSA health claim (EU 432/2012), a premium argument to include on the COA. Explicitly request this analysis from the laboratory.

Prove the quality of every lot

Rigorous quality control, from harvest to container, is what distinguishes a reliable supplier. Make sure you obtain the proof for every lot.

COA quality classifier — paste your values (acidity, peroxide, K232/K270/ΔK) → category and compliance in one click.

Request a quote — every lot delivered with a COA (IOC-approved lab), a sealed reference sample and traceability of the cold extraction.

Lead magnet: download our guide to olive oil quality control (harvest, extraction, IOC analyses, COA, thresholds).