The pattern which emerges in every case is a s et of profiles that underscore the basic picture. If thaw or partial thaw occurs for even a relatively short period of time, there are effects that go to the core of the product. In the summary diagram at the left, the typical pattern is shown. Exterior temperature rise rapidly to match the ambient air temperature and equilibrate rapidly. When the event is over, the exterior temperature drops rapidly to reflect the change in ambient air.
Interior temperatures are much slower to react.
Most significant is that interior higher temperatures fall much more slowly. The end result is that there is about the same cumulative exposure of interior and exterior of the food item. So, it can be assumed that if there is any type of significant thaw or partial thaw event, that the whole food item has been affected. This is important in consideration of monitoring frozen products. These illustrate the effectiveness of the CheckPoint approach to monitoring for partial thaw events.