In the food processing business, it is common knowledge that a clean working environment is crucial for products to be at their highest and purest quality. In order to ensure certain standards are met while maximising efficiency, Clean-In-Place (CIP) Systems are put in place.
The Chemicals of CIP Cycles
CIP systems work by pumping different sanitizing solutions to clean and rinse pipelines that products travel through to eliminate buildup. These solutions include caustic, acid, sterilizer, and disinfectant chemicals. The jobs of these CIP cleaning agents include reducing the surface tension of water, dissolving soil for easy cleaning, and rinsing away softening fats. In summary, it makes the cleaning process much more manageable. Although CIP systems without the use of chemicals can still meet a certain hygiene standard, it is much more time consuming and costly.
With that said, here are the four chemicals used in CIP cycles and what they do:
Caustic solutions, more commonly known as caustic soda, sodium hydroxide, or NaOH, are alkali solutions with exceptionally high pH levels. They are used at concentrations of 0.5 to 2.0 per cent to clean out soiled surfaces and even up to 4 per cent for heavily soiled ones. Caustic is also the main ingredient in many CIP cycles to help soften fats for easy removal. Non-foaming options are available to help reduce pump cavitation and improve overall pump efficiency.
Nitric acid is often used right after a caustic wash to stabilize pH levels and improve the efficiency of scale washing. Because it is used at concentrations of 0.5 per cent, it can work with temperatures lower than what is required by caustic solutions. In other words, it requires less heat.
Other acids include phosphoric acid, which is used to clean milk scale or milk stones commonly found in dairy processing plants.
Acid solutions are able to treat discoloured stainless steel by removing mineral stains that calcified on the metal surface. However, precautions must be taken as valve seats, and gaskets can break down when coming into contact with the solution.
Keep in mind when you deal with dairy products, avoid using acid wash after caustic solutions. If this happens, protein precipitation can result, making deposits much more challenging to remove.
Sanitizers and disinfectants are used to help eliminate microorganisms that would otherwise put public health and food safety at risk. Hypochlorite solutions such as sodium, calcium, and potassium have been the go-to sanitizers for many years.
In all of these chemical solutions, bleach is the active ingredient. As a result, they are relatively cheap to use and effective at getting rid of soils that are prone to microbial growth. Unfortunately, disinfectants can ruin a stainless steel surface, causing it to corrode and stain. It is also very harmful to the environment when introduced to waterways, as it kills off the good microorganisms that thrive in the ecosystem. To address this, hot water is sometimes used as a non-chemical disinfectant option, although heating it can incur high energy costs.
In more recent years, chlorine dioxide and PAA have come to replace bleach as it is safer for the environment, less corrosive to steel, and still more powerful than bleach.
As the name suggests, sterilizer solutions clean out the entire system from any organism. Although it can be done with chemicals, the most common way to go about this cycle is by using high-pressure steam. Although dairy and beverage processors do not need to be sterilized often, pharmaceuticals or ESL products use this cleaning method regularly.
Along with the use of these chemical products, extra tips like increasing the temperature and concentration of a solution helps effectively removing any soil buildups in a pipe. It is also worth noting that over time, chemicals lose their potency, and thus concentrations have to be adapted, or solutions replaced to maintain an adequate cleanliness level.