It is convenient for the hot air of food to come out, so that the food can be kept crisp and fresh in the box, and it will not be so soft and dry by the hot air that comes out so quickly. This principle is simple, because as we all know, cooked food-except cold food-gives off hot air. At this time, if fresh food is put in a closed box, hot air will condense quickly in the box or on the wall of the box when it meets cold air outside, and water vapor will dry the food in the closed box. If your food is fried and crispy, then these foods will be pitiful and cruel.

Therefore, in order to ensure that the food will not be softened and wet by steam during the time from the counter to the diners or from the McDonald's store to the home of the takeaway customers, McDonald's food box often has a hole. This will allow water vapor to come out instead of gathering in the box, making the food soft and unpalatable.

Moreover, as we all know, if an object is constantly emitting steam and it is hot, then in a closed space, the steam emitted by this object will affect the pressure inside and outside the box, making it very difficult to open the box, no matter what the material of the box is, whether it is plastic or paper box. So opening a hole in the box is not only to keep the food fresh, but also to let everyone open the box smoothly when eating.

In fact, not only McDonald's, but also many other take-away boxes will add some holes, which may be learned from McDonald's or thought of by themselves. I have to say that the service industry is becoming more and more considerate to customers.