It consists essentially of the proventriculus of a chicken (thus, the derivation of its name), dipped in cornstarch or flour, and deep-fried.

[2][3] A nutritional study conducted by the University of the Philippines Los Baños (UPLB) noted that, as with most street foods, the microbial quality of the proben is a concern.

However, the study noted that the pathogenic food-borne microbes in proben are mostly destroyed when it is cooked.

The microbes only return if the proben is stored at ambient temperature after having been cooked.

The study concluded that the risk of contamination can be reduced simply "through practice of personal hygiene employing standard cooking temperature (171–185 deg C) and time (10–15 min)" and by making sure that the proben is cooked just before it is eaten.