Place your packed product or packaging system on the vibration table. Make a sweep test from 1-100 hz or 1-200 hz. In a sweep test the vibration table does sinus vibration. Over time both frequency and amplitude is slowly changing. In low frequencies the amplitude will be large and in frequencies over approx. 20 hz you are almost not able to see the movement of the vibration table.
You can measure natural frequencies in the system by looking and listening. When a natural frequency is observed in the product then view on the control panel to have the actual frequency and note this in the report.
Alternatively the natural frequencies can be measured on an accelerometer in the packed product.