Final answer:
Cereal extrusion is a mechanical food processing method that subjects cereal grains to high temperatures and pressures, producing a puffed or shaped product. It begins with the preparation and cleaning of grains followed by cooking and shaping in an extruder. However, the process poses contamination risks thus safety measures are essential.
Step-by-step explanation:
The process of cereal extrusion involves several steps where cereal grains, such as wheat, barley, or rice, are transformed into puffed or shaped cereal products. First, the harvested grains are cleaned and prepared; any inedible hulls are removed through threshing and winnowing as with rice processing. Next, during the extrusion, the grains are subjected to high temperature and pressure in an extruder. This cooking process not only shapes the cereal but also gelatinizes the starches, making them more digestible. The extruder works by pushing the cereal dough through a shaped die. As the extruded product exits the die, it puffs up due to the sudden drop in pressure, giving extruded cereals their characteristic texture.
However, extrusion and other mechanical processing present the risk of introducing additional contaminants such as metallic fragments or microorganisms. In food safety, it is crucial to manage and minimize these risks to avoid equipment failure and potential health hazards to consumers. Various safety measures are taken, such as the use of filters in flour mills to prevent explosions caused by combustible grain dust in the air.