Although Romano cheese is traditionally made in Italy from ewe's milk (Pecorino) the following recipe is prepared for a 2 gallon version of cows milk (which would technically be called Vacchino Romano).
Strength is usually tested by measuring permanent deformation of the container. Hydrostatic testing is the most common method employed for testing pipes and pressure vessels. Using this test helps maintain safety standards and durability of a vessel over time.
So if the vessel (or pipe) has a design pressure or MAWP of 100 psi, then according to the codes, it can withstand a pressure of 150 psi without yielding. This hydrostatic test is a 1 time test to prove the structural integrity of the vessel or system.