Cream together shortening and sugar. Separately mash the bananas and add beaten eggs and vanilla to bananas. Add banana mix to creamed shortening and sugar. Mix. In separate bowl combine flour, salt, baking powder, and baking soda. Add some of flour mix and then alternating with some of the soured milk to creamed sugar/shortening. Keep alternating a few times until all ingredients are combined. Mix in nuts. Bake in greased loaf pan at 350 degrees for 1 hr (until knife comes out clean).