Citation: Ng, J.S.; Muhammad, S.A.; Yong, C.H.; Mohd Rodhi, A.; Ibrahim, B.; Adenan, M.N.H.; Moosa, S.; Othman, Z.; Abdullah Salim, N.A.; Sharif, Z.; et al. Adulteration Detection of Edible Bird’s Nests Using Rapid Spectroscopic Techniques Coupled with Multi-Class Discriminant Analysis. Foods 2022, 11, 2401. https://doi.org/10.3390/ foods11162401 Academic Editor: Marco Beccaria Received: 22 June 2022 Accepted: 3 August 2022 Published: 10 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). foods Article Adulteration Detection of Edible Bird’s Nests Using Rapid Spectroscopic Techniques Coupled with Multi-Class Discriminant Analysis Jing Sheng Ng 1 , Syahidah Akmal Muhammad 1,2, * , Chin Hong Yong 1 , Ainolsyakira Mohd Rodhi 2 , Baharudin Ibrahim 3 , Mohd Noor Hidayat Adenan 4 , Salmah Moosa 4 , Zainon Othman 4 , Nazaratul Ashifa Abdullah Salim 4 , Zawiyah Sharif 5 , Faridah Ismail 6 , Simon D. Kelly 7 and Andrew Cannavan 7 1 Environmental Technology Division, School of Industrial Technology, Universiti Sains Malaysia, Penang 11800, Malaysia 2 Analytical Biochemistry Research Centre (ABrC), Inkubator Inovasi Universiti (I2U), Kampus SAINS@USM, Universiti Sains Malaysia, Lebuh Bukit Jambul, Bayan Lepas 11900, Penang, Malaysia 3 Faculty of Pharmacy, Universiti Malaya, Kuala Lumpur 50603, Malaysia 4 Malaysian Nuclear Agency, Kajang 43000, Bangi, Selangor, Malaysia 5 Surveillance Branch, Food Safety and Quality Division, Ministry of Health Malaysia, Presint 3, Federal Government Administrative Centre, Putrajaya 62675, Malaysia 6 Veterinary Public Health Laboratory, Department of Veterinary Services, Bandar Baru Salak Tinggi, Sepang 43900, Selangor, Malaysia 7 Food Safety and Control Subprogramme, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria * Correspondence: syahidah.muhammad@usm.my Abstract: Edible bird’s nests (EBNs) are vulnerable to adulteration due to their huge demand for traditional medicine and high market price. Presently, there are pressing needs to explore field- deployable rapid screening techniques to detect adulteration of EBNs. The objective of this study is to explore the feasibility of using a handheld near-infrared (VIS/SW-NIR) spectroscopic device for the determination of EBN authenticity against the benchmark performance of a benchtop mid- infrared (MIR) spectrometer. Forty-nine authentic EBNs from the different states in Malaysia and 13 different adulterants (five types) were obtained and used to simulate the adulteration of EBNs at 1, 5 and 10% adulteration by mass (a total of 15 adulterated samples). The VIS/SW-NIR and MIR spectra collated were subsequently processed, modelled and classified using multi-class discriminant analysis. The VIS/SW-NIR results showed 100% correct classification for the collagen and nutrient agar classes in authenticity classification, while for the other classes, the lowest correct classification rate was 96.3%. For MIR analysis, only the karaya gum class had 100% correct classification whilst for the other four classes, the lowest rate of correct classification was at 94.4%. In conclusion, the combination of spectroscopic analysis with chemometrics can be a powerful screening tool to detect EBN adulteration. Keywords: edible bird’s nest; mid-infrared; near-infrared; adulteration; multi-class discriminant analysis 1. Introduction In the Chinese community, edible bird’s nest (EBN) is considered a premium food that boosts the health of an individual during sickness and aging [1]. EBN is the structure used by swallows where they lay their egg and shelter their young swiftlets [2]. The bird’s nest mainly comes from three genera of swiftlet, namely Aerodramus, Apus and Collocalia [3]. The nest is constructed using the saliva from the male swiftlet’s sublingual salivary gland [4]. Before the emergence of house-farming, the bird’s nest was obtained Foods 2022, 11, 2401. https://doi.org/10.3390/foods11162401 https://www.mdpi.com/journal/foods