Do bacteriostasis and fungistasis testing have to be performed for each lot of product in reference to the United States Pharmacopoeia (USP) sterility test?

No. This needs to be established only once for a specific formulation to determine the suitable level of
inoculate for that product. If the formulation has not changed for a number of years, periodic verification can
be done as microorganisms become resistant to preservatives in a formulation.