While traditional measurement methods of milk quality assessment are accurate but invasive and time-consuming, this study suggests a different approach, an innovative and non-invasive technique for milk quality assessment. This method estimates fat globule size using visible and near IR wavelengths. Fat globule size is a key parameter in dairy science since it indicates important milk properties such as creaminess, digestibility, and processing behavior.

In this study, reflectance data at various distances were collected using spatially resolved spectroscopy, with the light source projected onto raw milk. These diffuse reflectance spectra which were captured, were analysed as spectral parameters that correlated with fat globule size. The resulting method allows for real-time and remote monitoring, which makes it promising for industrial dairy applications.

The setup utilized ultra black surfaces behind the sample to minimize background reflections and stray light interference to ensure precision. For that, the black coating that was used is Acktar’s metal velvet, which is known for its extremely low reflectance. The use of this super black material aids in separating the true spectral response of the milk.

Acktar’s coatings and their blackbody-like properties were essential to the optical configuration and the performance of the experiments. The study illustrates how even in bio-tech and food industries, advanced black coating technologies play a critical role in enabling high precision optical systems. By combining sophisticated modeling with careful light control, this approach offers a new way to monitor milk quality non-destructively—bridging the gap between optical engineering and food science.

Fu X, Diaz-Olivares JA, van Nuenen A, Postelmans A, Saeys W, Aernouts B. Analysis of the fat globule size in raw milk through parametrization of visible and near-infrared spatially resolved spectra. Spectrochim Acta A Mol Biomol Spectrosc. 2025 Oct 15;339:126287. doi: 10.1016/j.saa.2025.126287. Epub 2025 Apr 23. PMID: 40306032.