A Slurpuff's nose is a remarkably sensitive instrument, capable of providing an understanding of the world comparable to human eyesight or Zubat echolocation, and detecting countless things unnoticed by eyes, ears, or weaker noses. For much of Kalos' history, this fact has seen these pokemon pressed into action to ensure the purity of the food supply.
Although some have thought to use Slurpuff like smoke detectors to warn for deadly chemicals, they are remarkably poor at handling poisons of any variety, and sicken too quickly to give any effective audible warning. Slurpuff will, however, only tolerate pure environments, for their sensitivity to all toxins is far higher than that of humans, and therefore their very presence can be proof of poison's absence – a fact which made them beloved by the kings of Kalos, who always feared being dethroned through assassination, especially in the form of food poisoning. Human tasters could be fooled by small portions or join conspiracies against the king, but the very presence of a healthy Slurpuff proved that the food was safe to eat.
In time, this custom spread to the nobility, for under feudalism it was not only the monarchs who had cause to fear assassination. It was even taken up by the peasantry, albeit for a different reason; although those with nothing had no cause to fear being murdered for their possessions, their poverty left them with far less ability to verify that their own food remained safe for human consumption, for rotten foods can be as dangerous as intentionally poisoned ones. Frequently, the Slurpuff protecting them and their lords was the same individual, for a Slurpuff's nose can typically cover an entire castle, and a noble whose serfs relied on rotted food could not rely on a healthy Slurpuff to guarantee their own safety.