You can look at this from the vantage point of your own home kitchen, or you can be particularly observant, if given half a chance to do so, when visiting sights that are part and parcel of the important food services industry. Chefs and restaurant owners may wish to jealously guard their culinary secrets, so it may not always be possible to visit their kitchens during lunch or dinner hours or after hours. But your neighborhood bistro or coffee shop owner may have established a friendly rapport with you, all thanks to your loyal patronage.
All you want to see is just how he manages to keep your favorite ingredients fresh and how those pastries and grills always seem to come out so picture perfect, always smelling like the Provencal countryside, or the Tuscan valley, whichever palette you prefer. You will always be in a good position to view the refrigerators of your local supermarket chain. These retail use fridges are at eye level, more or less, and opening and closing its doors is customer friendly. Look a little closer and you might just see that such doors are being kept tightly shut with Kason door closers.
The same goes for the ovens across the way at the deli counter, although peering across the counter would be a little challenging, especially when the queues are typically long. They are long not so much because folks are hungry and want to eat, but because the ingredients they love to sample are fresh and wholesome and the baked or grilled goods always seem to be toasted to perfection, always at the right temperature. Even if you were to microwave your takeouts at home, that door would need to be tightly shut as well.