Tunnel Pasteurization: Tunnel pasteurization is commonly used in aluminum can and glass bottle filling. Timing and temperature is calculated based on the number of required pasteurization units (PU). One PU defined as the micro death that occurs when the beverage is held at 60 °C (140 °F) for one minute.

Once bottles are filled with a food or beverage product and closed, they're sent on a conveyor belt from one side of the chamber to the other. The bottles undergo increasingly hot water temperatures until they reach pasteurization temperature.