Ethylene Oxide or Irradiation: How Disinfection-Grade Sanitary Pads Are Sterilised

A disinfection-grade sanitary pad differs from an ordinary-grade one by exactly one thing: an extra process step at the end. Disinfection.

Almost nobody outside the factory talks about how that step is done. It is worth knowing, because there are only two mainstream ways to do it in China, and which one a product went through tells you something about the manufacturer.

The two methods

The first is ethylene oxide — EO for short. It is old technology, thoroughly mature, and in China it sits under national process control. A plant cannot simply decide to run it; the process has to pass inspection by the relevant authorities.

The second is electron beam, usually referred to as irradiation sterilisation. The barrier to running it is lower, and once a batch has been through it, the goods can in principle move straight to dispatch.

Neither is automatically better. They behave differently, and that difference shows up in the schedule.

The difference that matters is time

Irradiated product can effectively ship the same day. EO-treated product cannot. After sterilisation it has to sit — a desorption or aeration period — until residues fall to a safe level. Only then can it enter the sales chain.

Underneath that sits a problem as old as sterilisation itself: kill efficacy and residue control are two targets that have to be met at the same time. Push hard enough on one and you start losing the other. Any method run well meets both. Any method run badly fails at one of them. GB 15979-2024 puts numbers on this rather than leaving it to interpretation — the residue limit right after disinfection and the limit at the point of sale are two different figures, and the second one is far tighter.

That gap between the two figures is the desorption window. It is the reason a disinfection-grade programme needs calendar space, and it is the reason a supplier promising instant EO-sterilised stock deserves a question rather than an order.

Why some manufacturers still choose ethylene oxide

There is a detail here that gets missed.

EO is used all over medical consumables — urinary catheters, infusion tubing, a long list of single-use devices. One reason is that it achieves sterilisation while keeping its effect on the material itself relatively controllable. Disinfect the product, do not damage the product.

For a sanitary pad that is not a small consideration. Hand feel, softness, absorption behaviour — these are sensitive to processing, and they are the properties the wearer actually notices. A method that sterilises thoroughly while flattening the topsheet or stiffening the core has solved one problem and created another.

So the honest framing is not that one process is more advanced. It is that sterilisation has to be matched to the material, and that is a trade-off, not a ranking.

Residue control is only one gate. It sits inside a wider set of production controls — incoming materials, in-process checks, finished-goods testing — which we set out in Sanitary Pad Safety Standards and Production Requirements.

What a buyer can take from this

Nothing here requires you to memorise process engineering. One heuristic is enough: a brand that states which method it uses, and how it controls residues, has usually thought about the problem. A pack that just prints disinfection-grade without a method or a disinfection date has skipped part of what the standard expects it to disclose.

For private label programmes, the practical question to ask a factory is short: which method, what residue figure do you release at, and can you show the test report. Three questions. A supplier who has run this properly answers all three without going back to check.

The standard has written the floor. Whether a manufacturer works above that floor is a separate matter, and it is the one worth asking about.

Li Genyuan, Foreign Trade Manager, Guangdong Nafei Industrial Co., Ltd.