Is Natural Henna Dye Free of Bacteria? On Microbes and How We Manage Them
Henna powder, made from ground plant leaves, naturally carries plenty of microbes. In MFDS testing, nine market hennas ranged from 220,000 to 11,000,000 CFU, while the cosmetic standard is under 1,000. Here is how Water Henna is sterilised to meet it.
Back at the office, the lab was measuring the microbes in our raw henna powder and in another henna for comparison. The photos were a little unsightly, so I hesitated a long time over whether to post — but in the spirit of keeping a record, here is a note on the microbes in natural henna. The short version: natural henna powder naturally carries plenty of them, so making it into a cosmetic requires sterilisation.
Natural Henna Naturally Carries Microbes
Microbes are everywhere — in red-pepper powder, in our own gut. There are bad ones like E. coli and mould, but beneficial ones too; mushrooms are fungi, and kimchi is full of lactic-acid bacteria. Henna powder, ground from plant leaves, is no different: it naturally carries a great many microbes.
How many? Across nine market hennas tested by the MFDS, roughly 220,000 to 11,000,000 CFU. In plain terms, about the same as red-pepper powder.
The Catch Is the Cosmetic Standard
Red-pepper powder is food, so it only needs to be free of the bad microbes. But natural henna dye is classified as a cosmetic — and a cosmetic must not exceed the limit for any microbe, good or bad, bacterial or fungal. The standard is under 1,000 aerobic microbes, which is effectively "none." Set against natural henna's 220,000 to 11,000,000 CFU, that is a very long way off. Such is henna in its raw state.
So How Do You Kill the Microbes?
The microbes have to go, and that is less simple than it sounds. Some are stubborn enough to survive boiling or scorching — and boiling or scorching henna destroys its ability to dye in the first place. You have to keep the colour while removing only the microbes.
The methods themselves are not hard to find; search "sterilising red-pepper powder" and plenty come up. Water Henna removes the microbes through a three-step technical process, which I will not detail as it is our know-how. But removing microbes that survive boiling and scorching, while leaving the dyeing power intact, is a process I find quietly astonishing every time.
Meeting the Law Is How We Keep It Safe
Watching quality control in the lab, there are a great many laws and standards to meet in making a natural henna dye as a cosmetic. Perhaps that is why so many companies leave manufacturing to an OEM and focus on marketing. Fortunately, our strength is in research and manufacturing, so we meet these exacting standards ourselves. It is demanding, but I believe this is precisely what lets our customers dye naturally with greater safety. If you are curious about the ingredients themselves, see Water Henna's eleven ingredients.