The biofilm formation on food-contact-surfaces is a serious threat for public health and often results in huge human and economic losses. Thus, it is of importance to develop new strategies that allow the monitoring of the biofilm formation on food-contact-surfaces. Such strategies permit effective and timely countermeasures and, therefore, to avoid the microbiological risk and associated environmental impact due to cleaning processes. Therefore, this work investigated a non-invasive method for monitoring and detection of the biofilm formation using Coda Wave Interferometry (CWI) method. The principle of this method and the calculation of decorrelation coefficient based on the ultrasonic measurements were explained. The results underlined that our developed method is able to detect the early stage of the biofilm formation of Staphylococcus aureus on the stainless steel. Namely, it is shown that the bacterial cell kinetic is well captured by the evolution of the decorrelation coefficient as a function of incubation times. Overall, this work showed that this cost effective CWI method is a promising tool for the detection of early stage biofilm formation on food-contact-surfaces.