Development of Bulk Acoustic Wave Sensors for Detection of Melamine in Milk and Infant Formula

Melamine, a synthetically produced compound, is considered as an illegal adulteration and also a contamination in dairy products. Food contaminated with the trace amount of melamine can result in the urinary calculi and the kidney failure. Health Canada has set a maximum tolerable limit of 0.5 ppm in infant formula and 2.5 ppm in other food products. Different techniques have been employed. However, they need expensive laboratory facilities, which is not applicable for the field test application. Therefore, there is a need for a real-time detection of melamine.

In this project, a Bulk acoustic wave (BAW) sensor was employed to detect trace amounts of melamine in the milk. Using thiolation chemistry, the gold electrode surface was modified to provide selective sensing. A change in mass loading on the crystal, results a shift in resonant frequency. By monitoring the resonant frequency versus the change in the melamine concentration, sensor specification is obtained. The preliminary results show that there is a decreasing trend of the resonant frequency with increase in the concentration of melamine. Bulk wave acoustic sensor has the potential to detect food adulterants such as melamine with higher specificity and sensitivity. The sensor will significantly aid the management of dairy products to preserve quality and thus quality of processed foods made from milk.