Dried oregano is the leaf of Origanum vulgare, harvested at or near flowering, dried and then rubbed and sifted to separate leaf from stem. It is one of the few culinary herbs with a Codex commodity standard of its own: CXS 342-2021, Standard for Dried Oregano, elaborated by the Codex Committee on Spices and Culinary Herbs, which fixes the definition, the styles and the essential composition and quality factors. Where a contract needs a reference that is not a private specification, that is the document to name.
Oregano matters commercially for a second reason. It is consistently among the most adulterated herbs in the European supply chain, because the leaf is cheap to imitate: olive, myrtle, sumac, cistus and hazel leaf have all been found in commercial oregano. Any serious buying programme treats authenticity as a routine test rather than as an exception.
Grades, cuts and calibration
Style. Codex distinguishes whole, rubbed and ground. Rubbed leaf is the mainstream culinary form: the dried herb is rubbed to release leaf from stem, then sifted. Ground oregano is a different product with a different surface area, a faster volatile oil loss and a different adulteration risk profile, because grinding hides everything the eye would otherwise catch.
Volatile oil. Oregano is a high volatile oil herb, and the volatile oil content is the primary commercial grading axis. Within that oil, the ratio of carvacrol to thymol defines the chemotype and therefore the sensory character; two lots at the same oil percentage can taste noticeably different if their chemotypes differ. A buyer with a fixed sensory target should specify the chemotype, not only the oil figure.
Stem and leaf. The rubbing and sifting step is what separates a culinary grade from a bulking material. A high stem share drags down volatile oil per kilogram and raises crude fibre, and it is the cheapest way for a seller to make weight.
Authenticity. Botanical verification runs on microscopy for leaf anatomy, on the volatile oil profile by gas chromatography, and increasingly on DNA and on non-targeted spectroscopic screening against reference libraries. A certificate of analysis that carries moisture and ash but no authenticity evidence is not addressing the risk that actually attaches to this commodity.
Seasonality and availability
Oregano is harvested at or just before full flowering, when volatile oil in the leaf is at its peak, in a window that runs from June into August depending on latitude and altitude. Cut material is dried, then cured in bulk before rubbing, because rubbing damp leaf shatters it into fines instead of separating it from stem.
Availability is year round from conditioned bulk, but volatile oil declines in storage, so age at shipment is a real quality parameter on this product in a way that it is not on a low-oil herb. A specification that sets a minimum volatile oil at the point of delivery, rather than at production, transfers that decline to the seller, which is usually where it belongs.
What the buyer checks at intake
- Botanical identity: Origanum vulgare confirmed, with the authenticity evidence the programme requires, whether that is microscopy, a gas chromatography profile, DNA or a non-targeted screen against a reference library.
- Style confirmed: whole, rubbed or ground, and the sieve fraction for rubbed and ground material.
- Volatile oil content against the contracted minimum, read on a dry basis and cross-checked against the moisture figure.
- Chemotype where the specification names one, because carvacrol-dominant and thymol-dominant oregano differ sensorially at the same oil percentage.
- Stem share and extraneous plant matter on a weighed sample; extraneous leaf of another species is the adulteration signal.
- Moisture, water activity and the ash split, with acid-insoluble ash read as the soil indicator.
- Treatment status in writing, and the microbiological panel that matches it.
Where it is used
Pizza, pasta sauce and Mediterranean-style seasoning are the volume applications, mostly in rubbed leaf, where visible leaf pieces are part of what the consumer is buying. Food service takes rubbed leaf in bulk. Retail private label takes both rubbed and ground.
Industrial seasoning blends for snacks, coatings and processed meats take ground oregano, where dispersion and consistent bulk density matter more than appearance and where the volatile oil target is usually set higher because the dose rate is lower. Oregano oil and oleoresin are separate products with separate regulatory treatment; do not conflate a leaf specification with an extract specification.
Standards and routes
Ambient dry goods handling, standard trailer or dry container, no temperature control. Oregano’s high volatile oil content makes barrier packaging more valuable than it is on a low-oil herb: an oil-rich leaf in a permeable pack loses aroma steadily, and the loss is not recoverable.
Where a lot has been irradiated, the pack and the commercial documents both have to carry the declaration required by Directive 1999/2/EC; the irradiation guide sets out the chain. Assurance normally runs through BRCGS or IFS Food, with authenticity controls sitting inside the supplier’s own HACCP and food fraud plans.
