Cleaning & SanitizingQuestion 135 of 319
Why might a quaternary ammonium (quat) sanitizer fail to disinfect a surface even when mixed at the correct concentration?
a.The label color faded in storage
b.The sink is made of stainless steel
c.The water was at room temperature
d.The water is very hard (above the limit on the product label, typically 500 ppm hardness)
Explanation
Quat sanitizers can be deactivated by hard water. If mineral content exceeds the limit on the product label (often 500 ppm, sometimes lower), the quat binds to minerals instead of microbes and loses effectiveness. Operators must follow the label and may need a water softener or a different sanitizer.
Law Reference: Cal. H&S Code §114099.1Practice all 319 questions free — no signup required.
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