Most pH meters cannot measure the pH of a solid. Perhaps if you break off a very small piece and mix it with water you could get an approximate pH, but the cheese will be a bit more acidic than what you test, due to water's pH of 7+-...wouldn't know how to swag a good number from the results....sorry.
The only meters I know of that can test a post-press cheese would be the extech 100 and 110 (there may be others, but not aware of them)...others such as milwakee, oakton and hanna can only test liquids.