One may not have smell, yet survive. The chemical particles of frying bacon mix with the air touch the very fine processes of the olfactory receptors, and thus we perceive an odor. The chemicals touch the hair. One may not have taste, yet survive. Life would certainly be less interesting if we could not taste food.
Taste occurs when minute particles touch the taste buds.
Smell and taste are very closely integrated, as I am sure you'll agree and have experienced. If we don't have touch, we and our patients would have great trouble surviving. I vaguely remember a study about the marked differences in behavior of newborns who were stroked or touched, and those who weren't. We have all seen movies or personally experienced where the unsighted person feels the face of another person. We have all touched a loved one with a caress, a subtle squeeze of the hand or a gentle stroke.