What is the best way to check the effectiveness of a sanitizer solution?

Using test strips specifically designed for the respective sanitizer is the best method to check the effectiveness of a sanitizer solution because these strips provide an accurate measurement of the sanitizer's concentration at the time of use. This is critical for ensuring that the sanitizer meets the necessary levels required for effectively killing pathogens and maintaining food safety.

Test strips are calibrated to indicate the concentration of the active ingredient in the sanitizer, allowing food safety professionals to confirm that the solution is still potent and suitable for use. Regular checking with test strips can help prevent harmful foodborne illnesses by ensuring that cleaning and sanitizing practices are up to standard.

The other options, such as testing using a sample of food, are not reliable because they do not measure the efficacy of the sanitizer directly. Trusting the manufacturer's instructions might give guidelines on dilution and usage, but it does not confirm the current effectiveness of a mixed solution. Checking the date of the sanitizer solution can help determine if the product is still viable, but it does not provide any direct evidence of its current effectiveness. Hence, utilizing test strips is the most reliable and effective approach.