Most of the alfalfa cubes produced in North America are exported to the Pacific Rim countries. The alfalfa cubes
may be exposed in transit to ambient conditions varying in temperature from below freezing to above 40.C and in relative
humidity up to 100%. Heat balance equations based on bulk thermal diffusion and natural convection were developed. The
governing partial differential equations were used to develop a numerical computer solution model. The temperatures of the
headspace above the cubes and the container ceiling were required for prediction of cube temperatures. The model predictions
agreed well with measured data during shipment of the cubes. Moisture transfer within the cube pile in the container was
modeled with the assumption of no moisture transfer with the outside air (i.e., completely sealed condition). However, the
calculated humidity ratio in the headspace was lower than the measured humidity ratio. It was therefore concluded that the
source of the extra moisture inside the container was due to moist air from outside leaking into the container. The calculated
spoilage potential agreed with the observation of mold on the cube. This model can be used to predict the onset of mold growth
during transit.