Thought from Today's Old Testament Passage:
As regards the dietary regulations, the division of species into clean and unclean (Lev. 11:1 ff.) is to be regarded not so much as a reaction against Egyptian totemism or the protest of a superior religion against contemporary pagan customs as the positive delineation of beneficial and noxious foods respectively. The specific concern of Leviticus 11:2 was with the kind of animal whose flesh could be ingested without any resultant harm to individual or communal health. Quadrupeds that were clovenfooted, parted the hoof, and chewed the cud were alone permitted for food. Such a designation of the ruminants proper excluded carnivorous and predatory species, and the list of possible animals was further restricted by the prohibition of swine, camels, hares, and coneys, which did not fulfill all the conditions necessary for "cleanness." It will be observed that the "clean" animals were exclusively vegetarian, and as such would be less likely to transmit infection than would the carnivorae, which fed on flesh that invariably decayed rapidly under conditions of a warm climate.
The prohibition concerning the flesh of swine is interesting partly on hygienic grounds, and partly because of the place that the animal occupied in Egyptian cult-worship. According to Herodotus, the pig was originally sacred to Osiris, and the cultic celebration of that deity involved the slaughter of a pig outside the houses of the participants.… It does not seem likely, however, that the question of cult-worship was quite as important a consideration in the prohibition of swine for food as were purely dietary and hygienic reasons. Even under the most carefully supervised modern conditions of slaughtering and processing, the flesh of the pig is far more potentially dangerous as a source of infection than that of any of the other quadrupeds normally eaten for food. …
Roland Kenneth Harrison, Introduction to the Old Testament (Grand Rapids, MI: William B. Eerdmans Publishing Co., 1969), pp. 604-605