Extrusion

Extrusion is the manufacturing process used to make about 95 percent of dry dog food in the US. Raw ingredients are mixed into a dough, forced through a die under high pressure, and exposed to brief but intense heat (around 200 degrees Celsius) which cooks the starches, kills pathogens, and gives kibble its characteristic shape and texture. Extrusion is efficient and produces shelf-stable food at low cost. Critics argue the high heat denatures some heat-sensitive nutrients, which is partly true. Manufacturers compensate by adding vitamins back after the cooking step. Most premium kibble brands use extrusion. The process itself is not the problem, the input quality is what matters.