Cleaning-In-Place — Ensuring Hygienic Standards Are Met

By Melissa Lind, contributing writer

Clean-In-Place — sometimes referred to as Sterilization-In-Place — is a commonly-used method of sanitization, particularly in the food and beverage industry. It is an automated process that removes the chance of worker error or injury.

Clean-In-Place (CIP) is a method for automized cleaning to remove food residue and bacteria from equipment, including containers and supply lines. Each system may vary slightly, but it generally involves six steps. The Standard CIP Method, depending on the type of equipment being used and the type of food being processed, the actual procedure may vary slightly. However, these basic steps are critical to comply with good hygiene standards.

Pre-Wash
Containers and supply lines are sprayed or flooded with warm water or a recycled sterilizing fluid to remove loose matter. The warm temperature also serves to pre-heat pipes and equipment surfaces.

Chemical Wash
In most cases, an alkaline chemical solution, such as Sodium Hydroxide (NaOH), is used to flood supply lines or spray surfaces. The chemical concentration, spray force, temperature, and duration of chemical contact may vary based on equipment and food type. Alternatively, in some cases, an acidic solution, such as Phosphoric Acid, may be used in this step.

Rinse
Water is used to flood supply lines or spray surfaces to remove chemical residue and any remaining food spoilage. Water temperature will vary from hot to cold, depending on the specifics of the machine and chemical type used.

Acid Rinse
If, as in most cases, an alkaline solution was used as the chemical treatment, an acid rinse will neutralize any remaining alkali residue. If an acidic chemical wash was performed, this step may be performed as an alkali rinse, but is not always required, depending on the chemical wash type.

Sterilizing Rinse
Surface areas and supply lines are rinsed with a sterilizing solution, different from the chemical wash.

Recycle
The fluid used in the sterilizing rinse can be recovered and returned to a holding tank. The used fluid can be recycled for use during the pre-wash of the next cleaning period.

In-process measurements should be taken with conductivity meters to ensure that solutions have the proper chemical concentration, pH, and temperature. They also ensure that each solution is checked as it is pumped out for re-use or disposal in an automated valve system.

There are some physical requirements that need to be met for the CIP system to function effectively. All of the pipes used to transport fluids must have smooth inner surfaces. Any crevices, including pipe threads, can trap solution from the prior step, resulting in contamination. Pipe fittings should be stainless steel, such as Din, IDF, RJT or Tri-clamp, to maintain hygiene standards.

CIP technology, like many systems in the food industry, is taking a step forward. Conductivity meters which are contact-based can lose efficiency after becoming coated with chemicals. This issue is being addressed by the development of inductive meters, which do not work through an electrode, but send a current through the solution for detection.