Which method is correct for checking sanitizer solution effectiveness?

The method involving the use of sanitizer test strips is the correct approach for checking the effectiveness of a sanitizer solution. These test strips are specifically designed to measure the concentration of disinfectants in a solution, providing an accurate assessment of whether the sanitizer is at the appropriate levels for effective disinfection. This is crucial in a food service environment, such as IHOP, where proper sanitation is vital to ensure food safety and prevent contamination.

Using hands to feel the solution is not a valid method because you cannot accurately determine the concentration or effectiveness of a sanitizer based on tactile sensation. Similarly, while a thermometer is useful for measuring temperature, it does not indicate the chemical effectiveness of a sanitizer solution. Visual inspection can sometimes provide clues about whether a solution is mixed correctly, but it does not give a quantitative measure of sanitizer concentration. Thus, sanitizer test strips are the only choice that provides a reliable and precise way to ensure that the sanitizer is functioning correctly.