Environmental Monitoring and Sanitation: A Look at CIP Systems

How Is Flow Generated? Pumps, valves, spray devices, and pipe diameter work together to create a flow rate.

• Valves create flow by pulsing (opening and closing). Flow is created when the pressure behind a closed valve is released. Often, valves are used to direct supply and clean the O-rings of the valves, which rotate when pulsed. Valve placement and pulse timing are also factors in restricting or routing flow.
• CIP systems must be designed with enough pump capacity to exceed soil build-up resistance, allow for valve back-flow pressure, meet spray ball capacity, completely fill pipe diameters, and maintain liquid velocity.

System Analysis and Root Cause Analysis. Poor cleaning is the No. 1 symptom of CIP failures. Other indicators include the creeping up of finished product indicator results (aerobic plate count, coliforms, E. coli, yeast/mold), pre-op allergen findings, a color bleed-through, or cleaning rinse water pH abnormalities. The CIP failures allow for incomplete soil or chemical removal. The longer that soils remain on the surface, the stronger they attach (think of dishes left in the sink overnight versus dishes cleaned shortly after use). Compounding the effect, sanitizers may be less effective because they do not have direct contact with microbial cell walls/ membranes, which is needed for microbial reduction/elimination.

On some CIP systems, software packages can be added that report system functionality, including flow rates, conductivity, temperatures, preventive maintenance prompts, or other sanitation verifications. These reports are valuable to detect system drift, unintended consequences of program changes, or equipment damage. Additionally, since day-to-day interior equipment/circuit inspection after cleaning and before sanitation is difficult or not conducted until preventive maintenance results in disassembling pipes or tanks, these metrics are tools to maintain system effectiveness.

Programming errors or changes can cause incorrect valve pulsing and sequencing, which may send cleaning solution down the wrong flow paths or release excessive amounts of heated solution to the drain. Additionally, incorrect valve pulsing may lead to decreased flow rates. Installation errors, such as incorrectly installed valves, process dead legs, and non-uniform pipe sizes, may result in unsanitary lines and bacterial contamination risk.

Temperatures of liquids that are above parameters for the soil can cause proteins to denature (unfold), exposing bonds that strongly adhere to surfaces. Liquids that don’t meet temperature requirements may not dissolve soils, as in the case of sugar removal. Thermocouples and resistance temperature detectors (RTD) can be used to measure the temperature in the system. As with any temperature measuring device, calibration must be conducted for accuracy.

Conductivity measurements indicate interfaces between ionic cleaning solutions and non-conductive water. Conductivity can be an indication of chemical concentrations and its removal from the system. The meter calibration must be maintained on a routine basis or drift can occur. If chemical concentration is in doubt, test kits provided by the chemical supplier can be used. Ensure that the reagents in the kit are not expired and that kit instructions are followed accurately. As a fast test, pH paper can be used to confirm acid or alkali presence, but should be followed up with a test kit for confirmation. Further, water hardness (calcium carbonate) and any mineral deposit build up will impact the effectiveness of the sanitizers used. Testing the parts-per-million (ppm), mg/L, or grains per gallon of calcium carbonate in the facility water will point chemical suppliers to the needed chemicals and temperatures for maintaining effective and efficient CIP functions (See Table 1, below).

Table 1. Water hardness classification measured as parts-per-million (ppm) or grains-per-gallon calcium carbonate.

In conclusion, a CIP system can deliver cleaning and sanitizing functionality with reduced operating costs. When issues arise, it is often due to system drift, minor operator adjustments that compound over time, not setting up, or trending metrics. While cleaning performance is a main CIP issue, the root causes are most often caused by reduced flow rate, a main component of temperature and chemical synergistic effect, followed by disparate temperature or conductivity values. Conducting consistent system analysis by measuring key metrics will drive CIP efficiencies and effectiveness.