Acceptance criteria for Growth Promotion Test Is factor of 2 . For GPT we inoculate less than 100 CFU .
Example : If we inoculate 60 CFU for GPT . Then the acceptance criteria is 30 CFU and 120 CFU . If USP recommend less than 100 CFU how can the acceptance criteria be 120 ? We are inoculating 60 organisms how can we expect up to 120 organisms according to the acceptance criteria .

Growth Promotion of the Media Media used for testing needs to be tested for growth promotion by inoculating the medium with appropriate microorganisms. It is preferable that test microorganisms be chosen for growth promotion testing.
Solid media tested for growth promotion is to be set up using pour plate method in order to determine a microbial plate count (CFU) which must be ≥ 70% of the microorganism inoculum’s calculated value. Inoculate portions/plates of Soybean–Casein Digest Broth and Soybean–Casein Digest Agar with a small number (not more than 100 CFU) of the microorganisms as (USP -BP-EUR)

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Hi as per my knowledge, Inaculation is different than result, it is recommended less than 100 cfu, but result may vary depends on many factors like pippeting handling etc…, if assay result of product is 100 percentage there would be limit like 98-102, it doesnt mean u should not get 101,