Milk Orange to make milk fat measurement more accessible

Milk Orange: sounds like a bizarre new brand of flavoured milk. In fact, it’s the world’s first fluorescent sensor that rapidly measures the level of fat in milk.

The light purple sensor is mixed with a milk sample and transmits fluorescent orange signals under light when fat is detected. The more fat present, the brighter the orange colour.

Developed by a National University of Singapore (NUS) research team, the sensor is being used with a device currently in development that will enable rapid, on-site measurement of milk fat. The researchers say it will be useful in applications such as dairy farms in developing countries. They also believe it could help enhance the current milk quality control process, particularly in areas with limited resources.

The NUS team responsible for developing Milk Orange. Image courtesy of National University of Singapore.

As fat content is associated with the levels of protein and vitamins in milk, it is directly correlated with the nutritional and marketing value of milk. Small-scale dairy farmers who sell milk to large organisations need an inexpensive way to detect the level of fat in milk. Such a device would help farmers separate and price the milk for sale, as well as enhancing the milk quality control process.

Current milk fat measurement methods are impractical - and often too complex and expensive - for use in such situations. To address this need, the NUS team set out to develop a method that is low-cost, easy to use and efficient.

The team screened more than 10,000 fluorescent dyes that are part of the Diversity Oriented Fluorescence Library (DOFL), which has been developed by lead researcher Professor Change Young-Tae over the last decade.

Having identified a light purple, non-toxic compound that responded well to increasing concentrations of milk fat, the researchers conducted further experiments to ensure that the compound responds only to fat and not to other milk substances such as proteins.

Professor Chang and his team are now working to develop a portable, convenient and inexpensive detector for rapid, on-the-spot milk fat measurement. They also plan to set up a spin-off company to commercialise the technology.

The researchers published a paper on the sensor in the journal Chemical Communications.