Concept · under Cleaning and sanitizing
Sanitizer strength: chlorine, iodine and quat ranges
Each chemical sanitizer has a working range in the FDA Food Code 2022: iodine at 12.5 to 25 mg/L, chlorine somewhere between 25 and 100 mg/L (the table below has the conditions for each band), and quat at the strength on its label. A test kit is how you know you're in range.
- ExamPFH
- Questions here7
- UpdatedOct 14, 2026
On this page 6 sections
Sanitizer works inside a window. Too weak and it leaves germs behind. Too strong and it leaves chemical on surfaces food touches. That's why every range on this page has a top as well as a bottom, and why the code wants it measured instead of eyeballed (4-501.116).
Strength is half the story; the surface has to be clean first, which is the whole point of cleaning vs sanitizing.
The ranges, chemical by chemical
| Sanitizer | Strength | Water at least | Contact time |
|---|---|---|---|
| Chlorine | 25–49 mg/L | 120°F (49°C) | 10 seconds |
| Chlorine | 50–99 mg/L | 75°F (24°C) at pH 8 or less; 100°F (38°C) at pH 10 or less | 7 seconds at 50 mg/L, else 10 |
| Chlorine | 100 mg/L | 55°F (13°C) | 10 seconds |
| Iodine | 12.5–25 mg/L, pH 5.0 or less | 68°F (20°C) | 30 seconds |
| Quat (quaternary ammonium) | Per the label; water hardness 500 mg/L or less | 75°F (24°C) | 30 seconds |
| Hot water | No chemical | 171°F (77°C) | 30 seconds, immersed |
Contact times also have to match the product's EPA-registered label. The 2026 Food Code kept every number in this table. How the three-compartment sink puts them to work is on cleaning and sanitizing.
Minimum water temperatures, on one thermometer
Reading a test strip honestly
- Dip for the time printed on the vial and read the color right away.
- Test the cloth bucket too. Wiping cloths sit in it between uses all shift (3-304.14).
- Swap a bucket that's cloudy or full of crumbs. The code wants it free of food debris and visible soil (3-304.14(D)).
- Know where the kit is kept. One has to be on site (4-302.14).
Strips and ranges
Which strip, which range, and what a bad reading means.
Each question is a chit, an order ticket. Answer it and it flips to show why every option is right or wrong.
No. 01
Which type of sanitizer test strip should be used for quaternary ammonium compounds?
Pick one. The chit flips to a note on every option.
Notes on No. 01
- A
pH strips pH strips measure acidity, not how much quat is in the solution.
- B
Iodine test strips Iodine strips are made for iodine sanitizers and won't read quat correctly.
- C
Chlorine test strips Chlorine strips react only to chlorine, so they give a false reading in quat.
- D
Quat test strips Correct: Each sanitizer needs its own test kit, and quat strips read quat concentration so you can match the label's range.
- A
No. 02
What should you do if the sanitizer concentration is too high?
Pick one. The chit flips to a note on every option.
Notes on No. 02
- A
Add more sanitizer to balance it out Adding sanitizer makes the solution even stronger.
- B
Let it sit until some evaporates Waiting is unreliable and leaves an unsafe solution in use.
- C
Use it anyway; stronger works better Too strong can leave a toxic residue on food-contact surfaces; more is not better.
- D
Dilute it with water to correct concentration Correct: Add water and retest until the strip reads within the label's range.
- A
No. 03
What should you do before using a new sanitizer solution?
Pick one. The chit flips to a note on every option.
Notes on No. 03
- A
Look at its color against the light Color can't show concentration, and many sanitizers look like plain water.
- B
Test the concentration with test strips Correct: Only a test strip or kit shows the concentration is in the label's range, strong enough to work and weak enough to leave no harmful residue.
- C
Feel it for a slippery texture Touching sanitizer exposes your skin to chemicals and tells you nothing about strength.
- D
Smell it for a strong bleach odor Smell is misleading; a weak bleach solution can still smell strong.
- A
No. 04
When using chlorine bleach as sanitizer, what factors affect its effectiveness?
Pick one. The chit flips to a note on every option.
Notes on No. 04
- A
Only contact time, nothing else Contact time matters, but it is one factor among several, not the only one.
- B
Only the water temperature Water temperature affects chlorine, but so do concentration and pH.
- C
Only the concentration in ppm The right ppm can still fail if the water is too cold or the pH too high.
- D
Temperature, concentration, and pH Correct: Chlorine works only within a set range of concentration, water temperature, and pH, and it also needs enough contact time; miss one and sanitizing fails.
- A
No. 05
How often should sanitizer concentration be tested during use?
Pick one. The chit flips to a note on every option.
Notes on No. 05
- A
Weekly A week is far too long; food debris and evaporation weaken a solution within hours.
- B
At least every 4 hours Correct: Sanitizer loses strength as food debris builds up, so kitchens test it at least every 4 hours and change it when it reads low or looks dirty.
- C
Once per day A single daily check misses the drop in strength that happens during service.
- D
When it looks wrong Looks don't tell you concentration; a clear solution can be too weak.
- A
No. 06
What is the proper concentration range for chlorine sanitizer in PPM (parts per million)?
Pick one. The chit flips to a note on every option.
Notes on No. 06
- A
0-25 PPM Most of this range is too weak; the Food Code allows as little as 25 ppm only in water at 120°F or hotter.
- B
50-100 PPM Correct: For chlorine in water at 75°F or warmer, the Food Code range is about 50–99 ppm; follow the label and check with a chlorine strip.
- C
500-1000 PPM 500–1,000 ppm is far too strong for food-contact surfaces and leaves harmful residue.
- D
200-300 PPM 200–300 ppm is stronger than allowed for food-contact surfaces and risks chemical residue.
- A
No. 07
How should sanitizer buckets be prepared at the start of each shift?
Pick one. The chit flips to a note on every option.
Notes on No. 07
- A
Fill with hot water only, no chemical Hot tap water is far below the 171°F needed to sanitize by heat, so a bucket with no chemical does nothing.
- B
Reuse yesterday's solution if it looks clear Old solution loses strength overnight, and clear-looking water can test far too weak.
- C
Mix fresh, test it, and label the bucket Correct: A fresh mix, checked with a test strip and labeled as sanitizer, gives the right strength and keeps anyone from mistaking the bucket for water.
- D
Add sanitizer by eye without measuring Guessing the amount gives a solution too weak to work or strong enough to leave residue.
- A
Nothing matches both filters. Clear one of them.
Bleach, ppm and quat
How much bleach goes in a gallon of water?
That depends on how strong the bleach in the jug is and what its label calls for, and bleach strengths vary. That's why the Food Code wants a test kit on site (4-302.14) and the strength measured with it (4-501.116) instead of a cup-and-bucket recipe.
What does ppm mean on a sanitizer strip?
Parts per million. The Food Code writes the same thing as mg/L, milligrams per liter, and for sanitizer in water the two numbers match.
Why does quat have no number in the code?
Quat products differ, so FDA Food Code 2022, 4-501.114(C), points to the label for strength, then sets water at 75°F (24°C) or warmer with hardness of 500 mg/L or less. The ranges for all three chemicals are also on the food handler flashcards.
Sources
- FDA Food Code 2022 — 4-501.111 hot water; 4-501.114 chemical ranges; 4-501.116 and 4-302.14 test kits; 4-703.11 contact times; 3-304.14 wiping cloths checked Oct 13, 2026
- FDA, summary of changes in the 2026 Food Code — sanitizer ranges unchanged checked Oct 13, 2026