Sanitizers are chemical solutions used to reduce harmful microorganisms on food contact surfaces to safe levels, preventing the spread of foodborne illness in commercial settings. The effectiveness depends entirely on the chemical concentration being correct. If the solution is too weak, it fails to kill pathogens. Conversely, a solution that is too strong can be toxic, damage equipment, and potentially leave harmful residues. Regular testing is a necessary step in the routine operation of any establishment that prepares or serves food.
Understanding Sanitizer Types and Testing Tools
Sanitizing agents approved for use on food contact surfaces generally fall into three main categories, and each requires a specific testing method. The most common is chlorine, often derived from sodium hypochlorite, which is widely used due to its effectiveness and low cost. Quaternary ammonium compounds, frequently called “Quats,” represent another class of chemicals recognized for their stability. Iodine-based sanitizers are also employed, although they are less common in foodservice operations.
Confirming the correct concentration for each agent is typically done using chemically specific test strips. These strips are designed to react only with the active ingredient of a single sanitizer type. Using the wrong strip, such as a chlorine strip on a Quat solution, yields a useless result. Health departments often mandate the use of these testing devices, following guidelines established by the FDA Food Code. Some operations may use liquid titration kits, which offer a more precise concentration measurement than the visual comparison provided by test strips.
Step-by-Step Procedure for Concentration Testing
The first step involves ensuring the water is prepared according to manufacturer specifications, especially regarding temperature. Water that is too hot can cause the chemical agent to evaporate quickly, making the solution ineffective, particularly with chlorine. For most sanitizers, the water temperature should fall between 75°F and 120°F to ensure proper chemical activity and accurate testing. After mixing, collect a small sample of the solution in a clean container, or dip the test strip directly into the sanitizing sink or bucket.
Next, immerse the correct test strip into the solution for the exact time specified by the manufacturer. This immersion time varies significantly between chemical types and brands. Chlorine test strips usually require a very brief dip, often just one or two seconds, to prevent bleaching the test paper. Quaternary ammonium test strips, however, often require a longer submersion time, sometimes up to 10 seconds, to ensure a complete chemical reaction.
After the specified immersion time, remove the strip without shaking off the excess liquid unless instructed otherwise. A short waiting period is then required for the color to fully develop on the reactive pad. This reaction time is also precise; for instance, some Quat strips may require a 10-second wait before reading. Comparing the resulting color to the reference chart on the strip dispenser reveals the concentration of the sanitizing agent in parts per million (ppm).
Interpreting Results and Corrective Action
The goal of testing is to determine if the solution concentration falls within the acceptable range defined by regulatory standards. Chlorine solutions must typically register between 50 and 100 ppm, depending on the water pH and temperature. Quaternary ammonium compounds generally require a higher concentration, often between 200 and 400 ppm. Iodine-based solutions usually require a range from 12.5 to 25 ppm.
If the strip indicates the concentration is below the minimum acceptable threshold, the solution is too weak to be effective against pathogens. The immediate corrective action is to add more concentrated chemical agent to the water and then re-test instantly to confirm the new concentration is correct. Conversely, if the test strip shows a concentration above the maximum allowable limit, the solution is too strong.
In this instance, the proper action is to dilute the mixture by adding plain water and then re-test immediately until the reading falls within the compliant ppm range. Solutions should be tested and adjusted at regular intervals, such as before each shift or every two to four hours. Testing is also required immediately any time the water becomes visibly dirty or the batch is changed.