The word "most putrescent" refers to something that is extremely rotten or decaying. The opposite of this could be "freshest," indicating something that is newly harvested or recently prepared. Another antonym could be "pleasing" or "delightful," referring to something that is enjoyable or pleasant in contrast to the repulsive nature of putrescence. "Cleanest" could also serve as an antonym, suggesting a level of hygiene and sanitation in contrast to the filth associated with putrescence. Other antonyms could include "wholesome," "healthy," or "invigorating," evoking a sense of vitality and well-being that is directly opposite from putrescent decay.