June 15, 2020
The International Organization for Standardization (ISO) approved a “method of testing cashmere and other animal hair fibers using peptide detection,” based on the proposal filed by Japan to the ISO, and issued the method as a new ISO international standard.*
This standard stipulates a method of: distinguishing cashmere and other animal hair fibers by a chemical analysis taking advantage of differences in the protein species contained in respective animal hairs; and also measuring blending ratios of the fibers.
This standard expects to contribute to: developing environments in which industries are able to test and assess types of animal fibers and blending ratios thereof based on scientific grounds; improving trust in transactions, distribution and trading of fiber products at home and abroad; and maintaining and vitalizing fair markets.
Background
Cashmere is popular, high-end animal fiber which is often used in the manufacture of clothing. Nevertheless, identification of species of animal hairs is difficult and distinguishing thereof requires sophisticated skills. Different species of animals often have hairs that are very similar in appearance such as cashmere and yak. In addition, it is very difficult to differentiate between animal hairs whosesurfaces are modified through special processing, even under very close inspection by a microscope. This problem of identification has led to the proliferation of counterfeit goods.
In this situation, industries have requested development of methods for testing cashmere based on objective data in addition to human eye-based inspection via microscope. In response, the ISO advanced development of a new international standard for such a testing method based on Japan’s proposal, which was led by the National Institute of Technology and Evaluation (NITE).
Outline of the international standard
Animal hairs are mostly composed of a protein called “keratin.” The new international standard stipulates a method of identifying animals by making use of slight differences in keratin genes shown between different types of animals.
In the method, experts pulverize the animal hairs, add a digestive enzyme called “trypsin” and dissolute the protein into “peptides.” These peptides are then analyzed using a “liquid chromatography/mass spectrometer (LC-MS).” This machine detects peptides that vary from species to species. Each species’ protein can be identified according to the size of their peaks that the machine outputs along a graph. The machine identifies species of animals from the specific protein that is displayed on the readout of the x-axis of the mass spectrometer (each peak is a different protein) and the relative volume of the hairs (the blend) based on the height (y-axis) of the peaks rising from the x-axis (see Figure 2) and calculate the blending ratios of animal hairs. The following diagrams illustrate the process.
Expected effects
This new international standard allows experts to distinguish animal hair fibers of six species of animals. This is the first standard for identifying such species by chemical analysis. These species are: camels, alpacas and angora rabbits in addition to the three species of cashmere, sheep and yak.. Different from the conventional eye-based inspection, this method is based on the genes of animals, and this permits experts to distinguish fibers based on objective, scientific data and to calculate blending ratios, without depending on the forms of the fibers. Moreover, it is simpler and more accurate than other test methods.
Looking at other countries, standardization activities have been advancing for the European Committee for Standardization (CEN), the Deutsche Industrie Normen (DIN), the Normes Françaises (NF) and the British Standards (BS). Against this backdrop, this new ISO international standard is expected to be adopted as national standards in other countries and be popularized worldwide. International dissemination of test methods that satisfy the standard is expected to improve the precision of distinguishing animal hair fibers, improving trust in distribution markets, promoting fair trade and enhancing consumers’ awareness of safe products.
*1: Official title of ISO 20418-3:2020
Textiles — Qualitative and quantitative proteomic analysis of some animal hair fibres — Part 3: Peptide detection using LC-MS without protein reduction
