You can press the meter into the top of the cheese and accept that you will have a mark , before pressing marks will go away , you can also press a little more after testing just enough to lessen mark then salt.
You can have a spare small cheese that you poke full of holes to get readings. It will be a little off as pressing speeds up ph drop a little from my understanding .
You can also cut away the protective plastic that surrounds the bulb and contact , just be more carful with it after that . You will still get a mark but it will be 1/4 the size.
Lastly you can take a sample of th cheese emulsify it and test, but it is complicated , Linuxboy has instructions of a sort somewhere on this forum .