Any scientific test can be influenced by methodology and the parameters set for the test.
If there is going to be consistency, there needs to be an agreed industry standard of testing, with the same methodology/parameters applied to all testing.
This would provide a baseline for making reasoned judgement rather than allowing for cherry picking of data to produce 'required' results.
Without a uniform testing process and parameters, any results can be manipulated to suggest good/bad qualities.
We've already seen too many ANTZ studies using dodgy methodology/parameters to produce scaremongering results. If juice suppliers start manipulating methods/parameters to produce skewed data in order to try and gain a commercial advantage, we're on a very slippery slope.