3.4 Cleaning & Sanitizing
Key Takeaways
- Cleaning removes visible soil; sanitizing reduces pathogens on an already-clean surface to safe levels - you must clean before you sanitize.
- The three-compartment sink runs wash (110 degrees F or above, detergent), rinse (clean water), then sanitize, with air drying at the end.
- Chemical sanitizer concentrations: chlorine 50 to 100 ppm, quaternary ammonium about 200 ppm, iodine 12.5 to 25 ppm.
- Hot-water sanitizing in a three-compartment sink requires immersion at 171 degrees F or above for at least 30 seconds.
- High-temperature dishmachines need a final rinse of at least 180 degrees F to bring the utensil surface to 160 degrees F.
Clean vs. Sanitize - Not the Same Thing
These two steps are tested constantly because they are easy to confuse.
- Cleaning removes visible food, soil, and grease from a surface using detergent and friction.
- Sanitizing reduces the number of pathogens on an already-clean surface to safe levels using heat or a chemical sanitizer.
You must clean first. Sanitizer cannot penetrate food residue or grease, so applying it to a dirty surface wastes the chemical and leaves pathogens behind. The rule to memorize: clean, then sanitize.
The Three-Compartment Sink
When a dishmachine is unavailable, manual warewashing uses a three-compartment sink in a fixed sequence. Before any of it, scrape and pre-rinse dishes.
- Wash - first sink, detergent and water at 110 degrees F or above
- Rinse - second sink, clean water to remove detergent
- Sanitize - third sink, hot water (171 degrees F or above) or a chemical sanitizer at the correct concentration
- Air dry - never towel dry, which recontaminates
Change the water when it is dirty or cold, and use a thermometer and test strips to verify temperature and concentration.
Chemical Sanitizers: Concentration and Contact Time
Three chemical sanitizers are approved for foodservice. The exam expects the concentration in parts per million (ppm) and that you verify it with test strips. Concentration too low will not sanitize; too high is unsafe and may leave residue.
| Sanitizer | Concentration | Minimum contact time |
|---|---|---|
| Chlorine (bleach) | 50 to 100 ppm | about 7 to 10 seconds |
| Quaternary ammonium (quat) | about 200 ppm (per label) | about 30 seconds |
| Iodine | 12.5 to 25 ppm | about 30 seconds |
The surface must stay wet for the full contact time - wiping it dry early stops the sanitizer before it finishes working. Water temperature, pH, and hardness all affect chemical sanitizers, so always follow the manufacturer's label.
Heat (Hot-Water) Sanitizing
Heat sanitizes without chemicals:
- Manual (three-compartment sink): immerse items in water at 171 degrees F or above for at least 30 seconds.
- High-temperature dishmachine: the final sanitizing rinse must be at least 180 degrees F, which raises the utensil surface to at least 160 degrees F - the temperature that actually sanitizes. Verify with a maximum-registering (irreversible) temperature device, not just the machine's gauge.
- Low-temperature (chemical) dishmachine: uses a chemical sanitizer (typically chlorine) in the final rinse instead of high heat.
Storing Cleaning Chemicals
Store sanitizers and cleaners away from and below food, single-use items, and equipment, clearly labeled in their original or properly marked containers - a physical-hazard and chemical-contamination control surveyors check.
An employee sprays sanitizer directly onto a cutting board that still has visible raw-chicken residue and wipes it off after two seconds. What is wrong with this practice?
A CDM tests the sanitizing compartment of the three-compartment sink with a chlorine test strip and reads 25 ppm. What does this indicate?
In a high-temperature dishmachine, what is the minimum final sanitizing rinse temperature, and what does it accomplish?