I have been checking for infestation for 12 years, I rarely find anything. When I do find it's an aphid, some thrips no mites & no miners. Going through the motions, doesn't qualify. If one knows a little more than others doesn't either qualify. There must be zero tollerance- NO INSECTS at all after checking.
I had many others check my product after I checked & they NEVER found anything after my checking. if the others were qualified checkers, then it shows that the mashgiach is qualified.
Anyone that checks by soaking, etc the vegies or fruit then checking the water is not qualified [test were made & they missed many of the insects].