Challenge test- “no increase” of mold
USP challenge test, for ex, calls for no increase of Aspergillus in 24 days (or something).
By “no increase,” hmmm, how strictly do they mean?
Do they mean no statistically significant increase? Or literally “equal to or less than” before?
I mean, if you plate out the same exact microbial sample at the same time in replicates, you get slightly different counts of bacteria/mold and that’s what I’m thinking about.
So say, if your initial count is 1.10 x10^6 CFU/mL and your final count after 24 days is 1.17 x 10^6 CFU/mL, just as an example, that can be an actual increase, OR, more likely, just plating error.
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