Why Perform A Product D-Value Study? Part 1

By Laurent Berliet and Silvia Rizzi, Mesa Labs France

Why would one be interested in performing a Product D-value study for an overkill cycle in which they are using a BI compliant with ISO 11138-3?

Determination of the thermal resistance (D-value and z-value) for the biological indicator in the liquid is required. This must be performed in a Biological Indicator Evaluation Resistometer (BIER) in replicate. The thermal resistance of each BI lot in the liquid should be determined. When a surrogate liquid is used for convenience, or because of microbial inhibition of the BI by the liquid, the thermal resistance in the surrogate must be determined.

Properties of the material being sterilized can significantly influence microorganism resistance / lethality especially for liquid products. In this article we discuss the non-heat sensitive products sterilized using Overkill method and the results expected from a D-Value study.