הלכה על חולין 115:49

Its laws are [for example,] that which they, may their memory be blessed, said (Chullin 67b), "'That swarms on the ground' - to exclude mites that are in lentils, worms (that are in aklusinim) [that are in klisin]" - which is a type of legume - "and worms in dates and cakes of figs." And the law is the same for all insects that are produced in the fruits internally after they are detached, and [the insects] did not separate from within them - that they are not [prohibited] by this negative commandment of that which swarms on the ground. And they are permissible from [the letter] of the law, except that there is a little disgust to the soul of the one that is eating them. And if there is a doubt if the insects were produced in the fruit before they were detached or afterwards, he should check for them properly. And if they are very minute to the point that he cannot check, he should wait twelve months. And afterwards, they are permissible to eat, from the outset, without checking. [This is] due to the principle known to our Rabbis, may their memory be blessed (Chullin 58a) that all insects of fruits do not exist twelve months. The explanation of, "do not exist," is to say that once twelve months have passed over it, it is like total dirt. And because of this, they, may their memory be blessed, said (Chullin 58b), "Those dates in the jug are permitted after the time of twelve months." And if the insects of the fruits separated into the air but they did not touch the ground, as when they went out from the fruit and fell into the mouth of the eater; and so [too,] if they separated and crawled on top of the fruit, whether we consider on the fruit to be on the ground; and so [too,] if the insect separated form the fruit and fell to the ground after it died - all of this is forbidden from the doubt if we determine and say that it like one that swarms on the ground or not.