Clean in Place (CIP)
Clean in Place is a method of cleaning the interior surfaces of process equipment and fittings, without disassembling them. Industries that rely heavily on CIP are those requiring high levels of hygiene, i.e. dairy, beverage, brewing, processed foods, pharmaceutical, and cosmetics and CIP is an integral part of automated industry. CIP is concerned with the removal of soil that can cause damage to quality of the final product being processed.
CIP method highly depends on type of soil or food residue to be cleaned. Every industry has their own type of soil depending upon the product being processed. And hence it is recommended to have CIP Process to be designed accordingly. Selection of chemicals and their strength, chemistry of product and its interaction with different solutions, time of interaction of chemicals with process line etc. are to be considered while designing the CIP line. Soil also differ in nature; it can either be simple water soluble or can be water insoluble. Water soluble one’s are easy to clean as simple flush of water can dissolve them. Water insoluble soils are hard to tackle as they are again divided into organic and inorganic soils. Organic ones include fats, oils, grease, proteins, starch, and carbohydrates. Inorganic soils include minerals, salt deposits, millstones etc.
CIP performs in two ways: – Single use cleaning CIP and recovery CIP. Single use cleaning is for that industries where the line gets way too dirty and chemicals once used can’t be further used due to high soil contamination in the chemical solution, but it is to be noted that they can be highly costly as new chemicals are to be used every time and they can have high environmental load as it is disposed and drained after every CIP Cycle. In Recovery CIP the process line is not so filthy and hence the chemicals can be collected and reused, though the equipment for recovering cleaning solution is more expensive.
CIP: Design Principle
Depending on soil load and process geometry, the CIP design principle is one of the following:
- Deliver highly turbulent, high flow-rate solution to effect good cleaning (applies to pipe circuits and some filled equipment).
- Deliver solution as a low-energy spray to fully wet the surface (applies to lightly soiled vessels where a static spray ball may be used).
- Deliver a high energy impinging spray (applies to highly soiled or large diameter vessels where a dynamic spray device may be used).
CIP systems have several advantages over the former manual cleaning. It has more consistent results due to accurate and rapid monitoring, due to less down time and fully automated process. Due to no need for dismantling of equipment and lesser manual work it lessens the burden on workers and human error. The Most important point is that it doesn’t compromise with quality as it provides consistency in the cleaning process.
CIP: Parameters to be considered
CIP effectiveness depends totally on the correct functioning of the 5 T’s.
Titration (1.5%): It is always important to select cchemical concentration in the supply tanks and in the circuits is in accordance to our need. It should be able to remove any deposits and residue of soil in the process equipment’s. It generally lies in the range of 0.5-2% and the optimal one being 1.5%.
Turbulence (1.5m/s): Flow velocity in all parts of the system should be sufficient to cause turbulent flow. This should be around 1.5-2 meters per second, below this laminar flow will occur which will not yield effective cleaning.
Temperature (~70°C): Temperature of the cleaning solution and water at the beginning & end of the circuit is important to consider. Temperature impacts on the rate of chemical reaction. Typical temperatures can be around 85 Deg. C for cleaning solution but for water it should not exceed 70 Deg. C
Time (15 min): Duration of each step of the CIP procedure and the total CIP time can be one of the important factor that shall be determining the cleaning is achieved or not. The standard time span should be 15 minutes.
Technology (Design): Total design of the complete line including all circuits to and from the chemical and water tanks should be proper. Even fault in the equipment design can result in cleaning of the line. Any corners or buildup site in the equipment will not full fill the CIP.
The standard procedure for CIP which needs to be followed after or between product run include 5 major steps.
- Pre-rinse: Water at temperature of about 40-60 Deg. C is used initially to remove any type of loose soil like melt fat and also for the water soluble materials such as sugar.
Note: Temperature shouldn’t exceed 60 deg. C.
- Alkali/ Caustic Circulation: Alkaline cleaning solutions dissolve proteins and saponify salts. The typical and most frequent alkaline agent used in the composition of the detergents is Sodium Hydroxide (NaOH), otherwise known as caustic soda.
- Intermediate Rinse: To purge out the alkaline detergent used and to remove the remaining soil, process line is flushed with water.
- Acid Circulation: Acid solutions are used for removing hard deposits such as milk stone (calcium phosphate) and water scale. The deposits are typically formed on hot surfaces and they cannot dissolve in alkalis. Acid solutions are most effective when used at pH 2.5 or lower & they leave surfaces without film. HNO3, H3PO4 are the most frequent acid agents used
- Final Rinse: To remove any trace of acid in the line, water is flushed.
Before starting production, the line is sterilized using disinfectants to inhibit any microbial activity to a certain level. It is always recommended to verify and validate all the cleaning procedure.
Repeatable, reliable, and effective cleaning in a manufacturing facility are prominent characteristic of the CIP system. Various influencing parameter are to be kept in mind as well as manipulated to achieve the required quality standard in manufacturing unit. The process can be validated hence it proves its authenticity. If proper care is taken in each stage of CIP including flow and temperature, it will provide safe environment for food manufacturing and processing owners.