Olfactory recepters sense smell of the surroundings .it helps to find the quality and the type of surroundings by smell . the smell of perfumes and the smell of food,wastes as well as the foul smell can be detected
Olfactory receptors are present in the nose.they sense any kind of it good or bad it senses the smell.these are very important for the and are the main reason for the sense of smell.but in case you have cold then your olfactory receptors do not work and thats the reason you dont sense the smell of food when you have a cold.