The Question posed on LinkedIn.

“Dehydrated Culture Media used in “Media Fill”. Does the powder specification need to be sterile (irradiated) or it can be sterilized by filtration (0.22µm) just after browth preparation in tank?”

My advice:

Your starting dehydrated media should meet your existing limits for raw materials with regards to microbial load.

If your standard procedure is to formulate your product in an ancillary room and sterile filter it on the way to the filling heads, then I would include this in your sterile media fill trials as it simulates your normal batch process.

A batch simulation with no interventions should demonstrate your filtration sterilises your “product”. Once that’s done, you can then incorporate interventions into your sterile media fill trials.