Milk quality control using fluorescence

17 Oct 2014. The first fluorescent sensor for milk fat has been developed to provide fast and quantitative milk fat determination.

A team led by Prof CHANG Young-Tae from the Department of Chemistry in NUS has developed a fluorescent sensor for milk fat, dubbed Milk Orange owing to its orange fluorescence. Milk Orange produces a bright orange fluorescence color when mixed with milk containing fat but not with skim milk. Based on the intensity of this fluorescence, the amount of fat in the milk can be accurately found to determine the quality of the milk. This enables dairy farmers and milk processors to quickly and efficiently conduct milk quality control, even on-site in the field, where the milk is produced, without waiting for laboratory analysis reports.

On-site instant milk quality control can thus be achieved. Based on the preliminary analysis of the dairy market, there is likely a significant demand for this capability. This could significantly accelerate the primary quality control process while reducing cost, which would help enhance the whole dairy industry.

Prof CHANG’s team has been developing novel and effective molecular fluorescent sensors for various important analytes of societal concerns such as caffeine and date rape drugs, and also environmental pollutants such as bisphenol-A. The method is now widely known as Diversity-Oriented Fluorescence Library Assay (DOFLA), which has pioneered in NUS. The results from this effort will greatly contribute to the number of important compounds that can be speedily and accurately detected in food and beverages, water supply and the environment.

changyt small

This cartoon describes both chemical and engineering aspect of the milk fat sensor. Initially the sensor is in non-fluorescent aggregated form. With milk fat added, the dye will be disassembled and exhibit its intrinsic fluorescence color. Together with a simple custom-built fluorescence detector, the fluorescence intensity can be measured and the milk quality evaluated on-site. <Image credit: Royal Chemical Society>


Xu W, Bai J, Peng J, Samanta A, Divyanshu, Chang YT. “Milk quality control: instant and quantitative milk fat determination with a BODIPY sensor-based fluorescence detector.” Chemical Communications 50 (2014) 10398.