First of all the issue here is not this Eucharist miracle, the issue is that personal experience is not limited to just the mind, as if one knew the theology this is obvious to what it is.
But anyway, first and foremost these type of questions can only come form minds like yours, as the Christian faith is based on Faith alone, not on what one can see or touch, I'll take a gamble and say that the church dosen't even want these things to happen for the reason I outlined above.
But since they happen it has a obligation to itself, to investigate all the so called miracles to it's own satisfaction only, not the satisfaction of anybody else especially to sceptics who have nothing better to do but try to instill holes in anything religious.
Now to your questions, if you watched the clip you would get an idea of what type of test were done.
Dosen't matter about reviews either by others, as other miracles that happened around the world and been tested independent in different laboratories have ended with identical results
The Vatican bounces the results off each other.
Plus on this particular one, my understanding is it's still under investigation, so no it's not an automatic process and it's thoroughly investigated, like I said not to your satisfaction, but also has to be careful for future technologies that will come about and debunk it, so it must be satisfied it's authentic, before declaring worthy of believe.
And yeah I'll be sarcastic, you are right, investigator have a personal interest especially if they are crime forensic investigators working under the law of the land which can face criminal investigation if known to be falsifying
There you go I gave you more then your usual one liners
