A method for estimating a level of damage to perishable cargo during transportation of the cargo using data collected by a portable monitoring device. The method includes measuring vibrational data associated with the cargo. The vibrational data is monitored by a vibration sensor of the portable monitoring device. The method further includes incrementing a counter in the portable monitoring device in response to an amplitude of the measured vibrational data exceeding a predetermined threshold. The method also includes determining if the counter value exceeds a predetermined value, and generating an alert indicating damage to the cargo in response to determining the counter value has exceeded the predetermined value.