IDEA - International Dialogue for the Evaluation of Allergens

Limonene and Linalool hydroperoxides study published

Published on 4 April 2019

IDEA's work on a market surveillance study on Limonene and Linalool hydroperoxides in finished consumer products has been published in Food and Chemical Toxicology.

The paper, 'Exposure source for skin sensitizing hydroperoxides of limonene and linalool remains elusive: An analytical market surveillance' by Andreas Natsch, Marco Nägelin, Hans Leijs, Michel van Strien, Elena Giménez-Arnau, Matthias Vey and Cécile González, was published in the Food and Chemical Toxicology 127 (2019) 156–162

The abstract of the paper is as follows:

"Positive patch test reactions of dermatological patients to oxidized samples of linalool and limonene are frequently reported. The sensitizing ingredients in the oxidation mixtures are hydroperoxides (HP). It is not clear whether fragranced consumer products are a relevant exposure source for HP. Analytical methodologies had been validated, allowing quantification of HP in different consumer products.

"The analytical approach was used to analyse 104 consumer products. Samples included aged and new samples from the same brand, products suspected by patients to elicit their symptoms and products containing essential oils. Only four samples contained>50 μg/g of at least one of the HP by the screening method. Confirmatory analysis by LC-MS methods indicated that levels are even below those observed by the conservative screening method. The samples retrieved from patch-test positive patients were below detection limit for all target analytes.

"This market surveillance indicates that concentrations of HP in consumer products and patient products are orders of magnitude below sensitizing doses in animal tests. No evidence for hydroperoxide accumulation in aged products or products used by patients was found. The nature and source of the inducing agent responsible for the frequent positive patch test reactions to oxidized terpenes remains elusive."