Sanitiser Strength and Contact Time

Domain 5 numbers, exactly as the exam asks them:

• Chlorine: 50-99 ppm for food-contact surfaces.

• Quaternary ammonium (quats): 200-400 ppm, or whatever the label states.

• Iodine: 12.5-25 ppm.

• Water temperature when mixing a chlorine sanitiser in a sink: at least 75 F (24 C).

• Contact time: follow the label; a 7-second wipe is not sanitising.

Three-compartment sink: wash, rinse, sanitise, then air dry. Never towel dry — a towel re-introduces pathogens.

Two rules that generate the most missed questions:

1. Clean before you sanitise. A sanitiser on food soil is not effective.

2. Never mix chemicals. A sanitiser must be approved and used at label concentration, never “a bit stronger to be safe”.

Numbers and sequence drilled here: FoodSafe Prep.