3-MCPD & Glycidyl Esters in Olive Oil: EU Limits Explained

A COA for a blended "olive oil" — refined oil cut with virgin — lands on a buyer's desk: acidity in range, peroxide low, K232/K270 clean. Nowhere does it mention 3-MCPD or glycidyl esters, two refining contaminants the EU has regulated since 2018 and 2021, and that a standard COA panel doesn't cover by default. For a buyer of blended "olive oil" or pomace oil destined for industrial frying or canning, that gap isn't paperwork — it's a spec that can get a shipment rejected on arrival. Here's what these two contaminants are, what the regulation actually sets, and what to require before signing.

What 3-MCPD and glycidyl esters actually are

3-monochloropropane-1,2-diol (3-MCPD) and glycidol aren't present in the olive or in freshly pressed oil — they're process contaminants, formed during industrial refining, mainly at the deodorisation step: steam injected under vacuum at high temperature, often above 200°C, to strip out the volatile compounds behind sensory defects. Under certain combinations of temperature, residence time and feedstock composition (chlorides, mono- and diglycerides), this step generates 3-MCPD fatty acid esters and glycidyl fatty acid esters. Once ingested, part of these esters splits back into free 3-MCPD and glycidol during digestion — a mechanism documented in several published studies on olive-based oils, including a study in PMC on the formation of these esters during heat-induced processing of olive oil.

Why virgin oils sit outside this issue

Extra virgin and virgin olive oil, extracted mechanically and never deodorised, simply doesn't have a pathway to form these contaminants. The issue concerns two clearly defined product families, covered in our guide to olive oil grades, from lampante to pomace: the "olive oil" denomination — a blend of refined and virgin oil sold in retail and foodservice — and olive-pomace oil, both of which go through a refining step. For a buyer sourcing extra virgin straight from a mill, the risk is close to zero. For a buyer of blended "olive oil" or pomace oil bound for catering, canning or industrial frying, this becomes a genuine spec line, on par with acidity or peroxide value.

What EU regulation actually sets

Two texts overlap, and their thresholds don't read the same way. Regulation (EU) 2018/290, which applied first, caps glycidyl esters — expressed as glycidol — at 1,000 µg/kg for vegetable oils and fats placed on the market for the final consumer or as a food ingredient, olive oil and pomace oil included, with coconut oil the sole exception at 500 µg/kg. Regulation (EU) 2020/1322, applicable since 1 January 2021, adds a limit for the sum of 3-MCPD and its esters, with a split few buyers see coming: 1,250 µg/kg for virgin and refined oils of coconut, maize, rapeseed, olive (excluding pomace), sunflower, soybean and palm kernel, but 2,500 µg/kg — double — for other refined vegetable oils, a category that explicitly includes olive-pomace oil alongside fish oils.

Contaminant	Regulation	In force since	Limit — olive oil (excl. pomace)	Limit — pomace oil
Glycidyl esters (as glycidol)	Regulation (EU) 2018/290	2018	1,000 µg/kg	1,000 µg/kg
3-MCPD + 3-MCPD esters	Regulation (EU) 2020/1322	1 January 2021	1,250 µg/kg	2,500 µg/kg

That asymmetry matters for any trading desk handling both categories: a pomace lot compliant against its own threshold would fail if it were labelled and sold as blended "olive oil". Reading a COA correctly means cross-checking the exact commercial denomination against the threshold that applies to it — a skill we cover in more depth in our guide to reading an olive oil COA.

Why pomace oil concentrates the risk

Published screening studies converge on the same pattern: the highest 3-MCPD and glycidyl ester levels turn up in pomace oils, well above virgin olive oil, which carries next to none. Two factors explain it. First, the feedstock: pomace is solvent-extracted, then refined under conditions that are often harsher than a standard lampante-oil refining run. Second, its chloride and mono-/diglyceride content — the direct precursors of these contaminants during deodorisation — a mechanism detailed in the European Food Safety Authority's opinion on process contaminants in vegetable oils. EFSA classifies glycidyl esters as genotoxic and carcinogenic, and 3-MCPD as a possible human carcinogen — which explains regulatory limits set in micrograms per kilo, several orders of magnitude below the acidity or peroxide values a buyer is used to.

How the testing actually works

3-MCPD and glycidyl esters are measured by gas chromatography coupled with mass spectrometry (GC-MS), following standardised, mutually equivalent methods: the ISO 18363 series (direct or indirect determination, depending on the part of the standard) and its equivalent, AOCS Cd 29a-13. This isn't a routine panel-test-level analysis: it needs a lab equipped for this specific pair of analytes, a turnaround often longer than a standard COA, and an added cost that's worth negotiating into a contract upfront rather than discovering after a rejected shipment. For a recurring volume in canning or industrial frying, that testing cost is cheap insurance against a lot stuck in customs or bounced by a customer running its own supplier audits.

What a quality team should require before buying

Three habits change the outcome for a buyer of refined "olive oil" or pomace oil:

• Ask for the test explicitly. Acidity, peroxide value and K232/K270 appear on almost every standard COA; 3-MCPD and glycidyl esters don't. They need to be added by contract, with the method and the lab named in the spec sheet.
• Check the denomination before comparing thresholds. A lot sold as blended "olive oil" must sit under 1,250 µg/kg of 3-MCPD; a pomace-oil lot under 2,500 µg/kg. Comparing the two on the same scale without verifying the product's regulatory denomination skews the compliance check.
• Ask the supplier about their refining process. A deodorisation run at a lower temperature, over a shorter residence time, or preceded by feedstock washing, cuts contaminant formation without changing the final sensory profile. It belongs in the spec sheet for any refining contract, alongside the acidity, peroxide and K232/K270 thresholds we detail in our quality parameters guide.

For a European brand or importer, compliance doesn't stop at the finished product's label — it traces back to the refiner's choice and process settings, well upstream of the container. That's a line item worth adding to any supplier audit checklist, alongside mill traceability and site certifications.

Where this fits in a wider supplier audit

Buyers who already run a structured supplier audit tend to treat 3-MCPD and glycidyl esters as an extension of the same due diligence they apply to acidity drift or peroxide creep — not a separate compliance track. The practical difference is timing: acidity and peroxide can be checked lot by lot on arrival, while a refiner's deodorisation settings are a process characteristic, best verified once at supplier onboarding and then spot-checked on a sampling basis rather than re-audited on every container. A refiner willing to share its deodorisation temperature and residence-time range, and to commit to periodic 3-MCPD/glycidyl ester testing rather than a one-off certificate, is signalling a level of process control that's worth more than a single passing lab result.

Securing your refined or pomace oil lots with Virginia

For a flow of blended "olive oil" or pomace oil bound for canning, industrial frying or catering, Virginia qualifies the requirement within 24 working hours and prepares, through its network of partner mills, a lot COA that can include 3-MCPD and glycidyl ester testing on request — beyond the standard acidity, peroxide and K232/K270 panel. An independent SGS counter-analysis remains available at loading to verify these parameters before any commitment, consistent with the quality assurances Virginia formalises on every lot. Request a quote and state the exact product denomination you're sourcing and the regulatory threshold it needs to meet.