Husk can refer to different materials in Scripture. It denotes the skin of a grape, a sack used for grain, and the pods of the carob tree. In the account of the prodigal son, it refers to carob pods, a food associated with the poorest people.
In the Passover-related law of Numbers, the word means grape skin; in the account of Elisha, it means a grain sack. In the parable of the prodigal son, it describes the food he desired while feeding swine.
Carob trees produce long, curved, brown pods with a sweetish taste. The pods were eaten as food, especially by the poor, and were also used as animal feed. The common identification with “St. John’s bread” is based on a mistaken association with John the Baptist.