Final answer:
Saliva neutralizes the food in the esophagus.
Step-by-step explanation:
The food in the esophagus is neutralized by saliva. When food is swallowed, it passes through the esophagus on its way to the stomach. The esophagus is a tube-like structure with muscles that propel the food forward through a process called peristalsis. The food is moistened by saliva, which contains enzymes that begin the process of digestion.