Holographic sensor for the rapid detection of milk adulteration
File(s)
Published version
Author(s)
Zhang, Yihan
Palacios, Maria
blyth, Jeff
Hu, Yubing
Yetisen, Ali
Type
Journal Article
Abstract
Milk adulteration through dilution and the addition of nitrogen-rich chemicals is a persistent issue in the dairy industry, affecting product quality and consumer safety. Current monitoring techniques often rely on protein nitrogen content, which can be misrepresented by these additives. We report a reflective holographic sensor that can directly detect diluted milk by monitoring the shrinkage of the holographic grating, which induces a rapid and reversible blue shift of 34 nm across milk dilutions ranging from 10 to 100 vol%. The holographic milk sensor demonstrates high selectivity, remaining unaffected by variations in fat content, ionic strength, or pH. Testing with various casein suspensions reveals that the shrinkage effect is specifically triggered by calcium caseinate micelles, in marked contrast to free casein slurries in water. Moreover, adding melamine to artificially compensate for the nitrogen loss in diluted milk results in swelling rather than contraction. This holographic sensor offers a reliable and effective tool for quality control in the dairy industry.
Date Issued
2025-07-10
Date Acceptance
2025-06-18
Citation
Applied Optics, 2025, 64 (20), pp.5852-5859
ISSN
1559-128X
Publisher
Optica Publishing Group
Start Page
5852
End Page
5859
Journal / Book Title
Applied Optics
Volume
64
Issue
20
Copyright Statement
© 2025 Optica Publishing Group. Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
License URL
Identifier
10.1364/AO.561321
Publication Status
Published
Date Publish Online
2025-06-23