A new published paper stopped me in my tracks recently — Isothiazolinone Detection in Dish Soap and Personal Care Products: Comparison of Lovibond Isothiazolinone Test Kit and Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry.
There’s an isothiazolinone test kit? Who knew?
According to its manufacturers, the test kit is designed for “cooling water” and “disinfection control” — in order, I presume, to check you’re using enough isothiazolinone to control bacteria, but not so much that you’re releasing unsafe / illegal quantities into the environment in your waste water.
But according to the published paper in the journal Dermatitis, “The Lovibond Isothiazolinone Test Kit (LITK) has been reported to successfully identify clinically relevant, occult isothiazolinones in patient personal care products” — and it is this claim which was examined by the researchers, although I do not know where it has been ‘reported’.
Although few products were tested and compared by the US-based team, it seems the LITK is extremely poor at detecting isothiazolinones in dish soap / cosmetic products, giving many false positives. This should perhaps hardly surprise — it was not designed for this purpose.
The real story here arguably is that highly accurate Mass Spectometry techniques identified three positive isothiazolinone cases — one each of MI, MCI and MI/MCI — in dish soaps where no isothiazolinone content was declared. Given nine supposedly isothiazolinone-free dish soaps were tested, it is extremely concerning that around a third of dish soaps could harbour MI or MCI and pose a risk to unsuspecting consumers, both already allergic and who may be at risk of becoming sensitised.
“Personal care products may contain undeclared isothiazolinones” conclude the authors. Indeed. And the same goes for household detergents, clearly. But what should be done about it?
Seems to me that the authorities in the US should be conducting far, far more spot checks on products on the market …
Testing kits, by the way, do exist for some allergens — people with nickel and cobalt allergies, for example, may well be familiar with the many affordable chemical spot test kits such as Nickel Alert that they can use to help them identify leaching metal ions in everyday objects — but a functioning and reliable and easy-to-use kit for those with isothiazolinone allergy would be a game changer.
The LITK clearly isn’t it, though, and was designed for a very specific purpose, for which I have no doubt works very well indeed. And given that it appears to retail at around $200, a product of that cost range would be out of the budget of many if a similar kit could be devised for isothiazolinone avoiders. I don’t know whether there are people working on an affordable test-at-home kit, but I sincerely hope so …