i believe also through manure. dairy cows are feed a diet high in grain because it maximizes their milk production. their stomach are not designed for a high grain diet, so they always have diarrhea. the cows shit often and anywhere and it splatters everywhere. when you are milking cows, you will get it on your clothes, in your eyes, in your mouth. ....
yes, this is the answer! patience! a proper boil that stays boiling until the pasta is done. no sticking ever. salt and oil are never needed in the cooking water.