The true statement among the options provided is:
A. A surface must be thoroughly cleaned before it can be properly sanitized.
Cleaning is a critical step before sanitization, as any debris or food particles can interfere with the effectiveness of the sanitizing process.
For further clarity:
B. Dishes are typically sanitized in hot water of at least 171°F (not 100°F) or with a chemical solution, so this statement is partly incorrect.
C. Food that has come into contact with chemicals is not automatically safe to eat after a period of time; specific guidelines on washing or waiting times must be followed to ensure safety.
D. While many restaurants have a two-compartment sink for washing and rinsing dishes, it is not mandatory for all restaurants, as some may use other methods or equipment, such as dishwashers.
Thus, A is the only true statement.