Dried herbs come from open fields. Dust, rain-splash and drying yards leave every raw lot with a microbial load that no serious buyer will accept untreated — total plate counts in the millions, plus the risk of Salmonella in the tail of the distribution. The question is never whether to treat. It is how.
Route one: ethylene oxide — effective, and effectively banned in Europe
EtO gas is a powerful sterilant, and it remains in use in some markets, including for spices in the United States. But fumigating foodstuffs with ethylene oxide is not permitted in the European Union, and the residues it leaves — ethylene oxide itself and its reaction product 2-chloroethanol — triggered one of the largest recall waves in recent EU food history, starting with sesame seed in 2020 and spreading through spices, herbs and additives. Since then, EtO is one of the first things a European importer screens for on high-risk origins.
The practical consequence: a lot treated with EtO anywhere in its history is a liability in the EU, whatever the certificate says. If your product may ever cross into Europe — or into a brand that sells there — EtO closes doors.
Route two: irradiation — legal, but it goes on the label
Ionising radiation is authorised in the EU for dried aromatic herbs and spices, and it works. But it comes with two commercial problems. First, EU rules require irradiated food to be labelled as such — "irradiated" or "treated with ionising radiation" — all the way to the consumer pack. Second, organic certification excludes it, and many conventional tea and infusion brands avoid it purely on consumer perception. Radura symbols do not sell chamomile tea.
Route three: saturated steam — physics instead of chemistry
Steam sterilization attacks the same microbial load with heat and moisture instead of chemicals or radiation. Done properly, it leaves nothing behind: no residues to screen, no labelling obligation, no conflict with organic or "clean label" positioning. That is why "steam-sterilized" has quietly become the default expectation in European herb and tea buying.
"Done properly" is the operative phrase. Herbs are not canned soup — overtreat them and you cook away the volatile oils and colour that you were paid to preserve. A credible steam process is therefore a validated one:
- A defined lethality target — we work to a 5-log reduction standard, demonstrated with surrogate-organism trials rather than assumed.
- Cycle records per batch — temperature, pressure and accumulated lethality (F₀) logged, not just a green light on a panel.
- Post-treatment moisture and aw control — steam adds water; the process must take it back out and prove it did.
What to ask your supplier
Whoever you buy from, three questions separate a validated process from a marketing claim:
- What log-reduction is the process validated to, and against which organism?
- Can you attach the cycle log (F₀) for my batch — not a generic one?
- What are the moisture and water-activity readings after treatment?
At Fayum Botanicals the answers ship with every lot as part of the lot passport, and exporters who want to sell "steam-sterilized" without building a line can use our toll sterilization service — certificate and cycle log included, per batch.