What is the typical concentration range for quats when sanitizing surfaces?

• A. 50–100 ppm
• B. 12.5–25 ppm
• C. 500–700 ppm
• D. 200–400 ppm

Answer: (D)

Quats are used as surface sanitizers in food-service settings, and the effective range for sanitizing is typically 200–400 ppm. This concentration is high enough to inactivate common pathogens within a standard contact time (about 30 seconds to a minute) while staying practical for routine use and minimizing residue or surface damage. If the solution is much lower than this range, sanitizing won’t be reliable. If it’s higher, you may run into residue issues and safety or label limits. Always follow the product label for the exact ppm and verify with test strips, and ensure the surface is clean first, since organic matter can reduce effectiveness.