Why must sanitizers have correct concentration and contact time?

• A. To improve the flavor of foods.
• B. To achieve effective microbial kill.
• C. To shorten cleaning time.
• D. To eliminate the need for water during cleaning.

Answer: (B)

Sanitizers must be used at the right strength and kept on the surface for a sufficient period to reliably kill microbes. The correct concentration provides enough active chemical to attack and disrupt the microbes’ cells, while too-low concentration won’t achieve the needed reduction and may leave pathogens behind. The required contact time ensures the sanitizer remains in contact with the surface long enough for the chemical reactions to occur and for microbes to be inactivated. Factors like soil load, temperature, and surface material can affect both concentration and contact time, so the label specifies exact conditions and the surface must be cleaned and kept wet for the full duration. If the surface dries early or coverage is uneven, the sanitizer cannot work effectively. Water is still needed for rinsing or diluting according to the product, and sanitizers are not intended to improve flavor or automatically shorten cleaning time.