Retort Validation includes Temperature Distribution, Heat Distribution and Heat Penetration Studies.

Temperature Distribution Tests are designed to ensure that the sterilizer is at a uniform temperature, at the start of the process timing and throughout the cycle in all areas of the sterilizer. TD studies must be designed to locate the slowest heating area in the sterilizer and to determine the parameters required to bring that area of the retort to a minimum uniform temperature throughout the process cycle.

Heat Penetration Study : The purpose of the heat penetration study is to determine the heating and cooling behavior of a product / package combination in a specific retort system for the establishment of safe thermal process and evaluating process deviations. The study must be designed to adequately examine all critical factors associated with the product , package and process which affect heating rates.

Heat Distribution Study : is mandatory for Steam/ Air retorts. HD study is performed to determine a correlation between the retort temperature and the lethality obtained by the product. HD study helps to determine the heating variations due to air pockets. If air pockets are present, the lethality varies amongst the containers significantly, even if the retort temperature remined constant.

For each sensor placed in the cold spot of the container, a corresponding sensor would need to place in the retort immediately outside of the container , in order to determine the correlation between the retort temperature and the lethality obtained by the product. The HD study helps to identify the cold spots within the retort that would not be detected with a temperature distribution study.