That should be appropriate. Normally what one would expect to see, and again, my background
is more in the biotech processes, so if I err for classical fermentation, someone else please step
in, but what we typically see is all the media, all the transfers performed in aseptic fashion.
Essentially, the early stage manufacturing, that is the subculture and fermentation for biotech
process is done in aseptic fashion. Once you’ve got to the harvesting stage, it really is a
bioburden control situation. So if you are sterilizing the material that’s going in and running the
fermenter and then harvesting, that would seem to be an appropriate level of control.
The normal procedure in classical fermentation would be to steam it, sterilize it in place, and then
introduce the cell, and that’s been practiced for probably more than 35 years. It goes back to the
original production of liquor. Concerning the feeds, the question is whether or not the feed
materials, whether they’re nutrients or pH adjustment buffers need to be sterilized and whether
the lines leading from those vessels into the fermenter need to be sterilized. Look for a practical
solution here. If a system is set up in such a way that it’s running trouble free, than maybe it’s not
necessary, but if there are problems associated with those materials, if they’ve not been
sterilized, then it is clearly an issue that needs to be addressed.
