Why is pork considered dirty?

Chef's answer
Pigs "cheweth not the cud" because they possess simple guts, unable to digest cellulose. They eat calorie-dense foods, not only nuts and grains but also less salubrious items such as carrion, human corpses and feces. Pigs were unclean because they ate filth. The Jews were not alone in this prejudice.
Frequently asked Questions 🎓
According to the Torah, land-dwelling animals that both chew the cud (ruminate) and have cloven hooves, are kosher. ... Quintessentially, the Torah explicitly declares the pig unclean, because it has cloven hooves but does not ruminate..
Of those that live in the water (including fish) only those that have fins and scales may be eaten. All crustaceans and mollusk shellfish have no scales and are therefore unclean. These include shrimp/prawns, lobster, scallops, mussels, oysters, squid, octopus, crabs and other shellfish) is not clean..
A few more cooking questions 📍