Or HaChaim on Leviticus 11:43/אור החיים על ויקרא י״א:מ״ג

1 אל תשקצו את נפשותיכם, "Do not make something detestable out of your persons, etc." Why did the Torah repeat this commandment? Torat Kohanim writes that this includes separate culpability for someone who after having contacted the dead part, let it go, and then touched it again. Granted that what is stated in Torat Kohanim is true and that one is indeed culpable for repeated contact with carrion, why did the Torah have to write this? Who would have imagined that the second time one contacted the carrion one would not be culpable? Perhaps the verse wants to inform us that if someone eats these swarming things his soul will become something detestable and the Torah warns us in clear terms not to cause our souls to become something detestable. The Torah hints at the same time how much or how little of such carrion will have such an effect on our souls. Look at what we have written on Genesis 1,26 on the words וירדו בדגת הים, "and they are to have dominion over the fish of the sea, etc." You will find there that our sages in Pessachim 49 referred to עמי הארץ, unlearned and therefore not truly observant Jews, as שקץ and that they compared the daughters of such people to שרץ also. All such statemnents of our sages are inspired by the Holy Spirit. These words are identical to what we have written here.

2The Torah says here ולא תטמאו בהם, "do not make yourselves unclean with them." We need to be very circumspect concerning anything which may possibly infringe on this warning. Whenever we are in doubt about contacting something which may or may not fall under the category of things that would confer impurity on our souls we must avoid such things at all costs. There is no vegetable or other produce which is not infested with some of the things which are detestable; we must therefore be most careful in examining all such produce before consuming it.