A food recall occurs when there is reason to believe that a food may cause consumers to become ill. A food manufacturer or distributer intiates the recall to take foods off the market. In some situations, food recalls are requested by government agencies (USDA or FDA).
Some reasons for recalling food include:
Discovery of an organism in a product which may make consumers sick
Discovery of potential allergen in a product
Mislabeling or misbranding of food. For example, if a food contains an allergen, such as nuts or eggs, but that ingredient does not appear on the label.
Recalls and Alerts (foodsafety.gov)