Food and pharmaceutical safety depends largely on ensuring that production processes are free from any cross-contamination and residues that could compromise the final quality. Consumers expect safe products, and companies risk both their reputation and compliance with strict international standards.
In order to guarantee this safety, industries implement different technical solutions in their production processes. One of the most proven solutions, due to its efficiency and effectiveness, is the use of on-site cleaning and disinfection systems, known as Clean-in-Place (CIP)[1] .
What is a CIP system (and when is it complemented by SIP)?
A Clean-in-Place system is an automated technical solution that is activated when a production process is stopped, either due to a batch change or scheduled cleaning.
Its purpose is to perform two essential actions in situ:
- Cleaning and removal of product residues that have been deposited in the facility.
- Disinfection to remove existing biofilm (biofilm being understood as the layer of bacteria or microbes that adhere to the surfaces of the facility).
A typical CIP process is outlined in the following illustration:
Illustration 1: Standard CIP process
Source: TMI
(e.g. in pharmaceutical or sensitive product applications), CIP is complemented by SIP (Sanitisation-in-Place)[2] , which incorporates advanced thermal or chemical sanitisation procedures.
Advantages and disadvantages of CIP and SIP.
The adoption of CIP and SIP systems is indisputable if effective and efficient cleaning and disinfection are to be guaranteed.
The major benefits they offer in terms of operation and safety are:
- Reproducible and standardised processes.
- High capacity for automation.
- Reduced downtime.
- Reduction in human error.
- Guaranteed food safety.
On the other hand, some of its drawbacks are:
- High cost.
- Not always suitable for highly adhered or insoluble waste.
- Requires a more sophisticated solution design.
Associated hygiene standards.
CIP/SIP systems are common in industries subject to high hygiene requirements: pharmaceutical, food and beverages. They are commonly used in industries where quality assurance systems are well established and follow high international standards, such as:
- BRCGS: Brand Reputation through Compliance Global Standards, formerly known as BRC (British Retail Consortium).
- GMP: Good Manufacturing Practice.
- GFSI: Global Food Safety Initiative.
- FSSC: Food Safety System Certification.
- SQF: Safe Quality Food.
Hygienic design, process traceability and microbiological validation are mandatory in these environments, making CIP a key part of quality assurance.
Key points for designing an effective CIP/SIP system.
The critical factors that determine the effectiveness of a CIP or SIP system are traditionally summarised in the principles described by Lelieveld, Holah and Napper[3] , and later systematised by Sinner.
Cleaning chemicals.
Cleaning chemicals in a CIP system must have different characteristics to deal with the residue to be cleaned. Properties such as wetting, suspension and emulsion power are important to ensure effectiveness when interacting with the residue.
It is also important to consider other aspects when selecting them, such as their effectiveness in cleaning the product to be removed, environmental criteria, safety in use, food grade, etc. All existing detergents fall into three categories: alkaline, neutral and acidic.
Disinfectant.
Important for eliminating or reducing the presence of biofilm, formed by microorganisms and pathogens, which may still be present after the cleaning process.
There are mainly two types of disinfectants: oxidising and non-oxidising. Each type offers a wide range of possibilities with their own advantages and disadvantages, so to ensure proper disinfection, you should choose one that guarantees that no product residue remains on the cleaned surfaces.
Detergent concentration.
The proportion of detergent to be used in the cleaning process must be adjusted according to the type of product to be cleaned. An excess of detergent can be counterproductive, to the point of increasing cleaning time and/or damaging the materials used in the facility.
Temperature.
Temperature is very important in CIP and SIP systems. Studies have shown that cleaning time is inversely proportional to temperature. However, it should be noted that high temperatures can also have a negative effect depending on the type of detergent selected.
Mechanical effect of flow.
All components used to project cleaning, disinfecting and sanitising fluids during the CIP and SIP process are generally known as spray balls. Optimal selection and arrangement are required if the system is to achieve maximum effectiveness and efficiency.
Illustration 2: Types of spray balls
Source: https://sanimatic.com/spray-devices-supply-tubes/
Time.
Although longer times usually result in more effective cleaning and disinfection, time is a limiting factor that we always seek to reduce, as this means that the production process will be stopped for as little time as possible.
Setting or estimating the target time is not trivial, as it depends on other factors such as: the type of residue to be cleaned, the type of installation to be cleaned, the detergent, the temperature, etc. In addition, once established, a validation process will be required when the installation is operational.
Process control.
As already mentioned, the process in CIP systems is automated. However, depending on the technical difficulty of removing product residues, it may be necessary to dismantle certain parts of the installation manually to facilitate access.
Whenever possible, the automated option offers greater safety and effectiveness, as it almost completely eliminates human error and guarantees the repeatability of the process.
Illustration 3: Cleaning manifold and automatic cleaning process control panel
Source: TMI
Water quality.
Water is the main element in a cleaning process, and the one with the highest consumption. It must transport and react efficiently with the detergents used and flow through the elements arranged to remove product residues and disinfect.
Therefore, the quality of the supply must be controlled through specific treatments. Failure to do so may result in the process not meeting the levels required in subsequent laboratory controls.
Table 1: Water quality for a CIP system
Source: Holah, 2003
System coverage.
To achieve maximum efficiency and effectiveness in CIP and SIP systems, these solutions must be designed in such a way that all parts of the installation to be cleaned are reached. Therefore, the system must provide total coverage so that no parts are left uncleaned and disinfected.
Post-application control of the CIP and SIP system by dispersing riboflavin with ultraviolet light is a highly proven solution for validating the required efficiency and effectiveness.
Illustration 4: Spray Ball in tank with riboflavin residue viewed under UV light
Source: Holloway America
Hygienic design.
In hygienic design, every detail is important, even more so when it comes to CIP and SIP systems.
Today, we have procedures such as Hazard Analysis Critical Control Point (HACCP[4] ) in which potential biological, chemical and physical hazards are identified at each stage of the food production process.
Due to the difficulty of this type of analysis, it is recommended that it be carried out with the involvement of experts in different areas of knowledge, such as process operation technicians, quality control and laboratory technicians, technicians from the manufacturers of the equipment involved, etc.
There are also good practice guides and regulations related to hygienic design, such as EHEDG[5] and ISO-1672 respectively, which help us when implementing this type of solution.
Some of the most important points to consider in hygienic design are:
- Selection of materials that come into contact with the product: steels, elastomers, plastics, etc. Considering their suitability and the surface finish they should have to facilitate cleaning and disinfection.
- Selection of components: valves, sensors, pressure switches, levels, spray balls, flanges and connections, etc., must also be hygienic.
- Elimination of dead legs throughout the installation.
Illustration5 : Surface roughness reading on AISI-316 2B stainless steel part
Source: TMI
Operation and quality control.
Operating teams involved in all manual tasks must be trained to supervise CIP and SIP systems.
Associated quality controls are also extremely important, as they ensure that the system is effective. Controls before and after the application of the CIP and SIP systems, by taking samples from the surfaces of the installation, allow cultures to be carried out in the laboratory to show the microbiological status of the installation. By counting these microorganisms, known as colony forming units (cfu), the effectiveness of the CIP and SIP systems is evaluated.
Everything discussed so far has a direct application, as could not be otherwise, in technical bagging solutions[8] . Bagging equipment is in direct contact with different types of food and pharmaceutical products. Therefore, the design of this equipment must take into account all the key factors mentioned above.
Sinner’s approach: time, detergent, temperature and mechanical action.
To complement what has been discussed in the previous paragraphs, we will now mention the analysis of another expert in the field, Sinner (1960). He defines four key and interdependent factors to ensure maximum effectiveness in CIP and SIP systems: time, detergent, temperature and the mechanical effect of fluid flow.
Sinner’s diagrams summarise how these four parameters relate to each other.
An increase in one of them (e.g., mechanical action or temperature) allows the duration of the process to be reduced without compromising effectiveness.
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Illustration 6: Sinner diagrams, updated
Source: Alfa Laval Tank Cleaning Equipment A/S
Innovation and continuous improvement in CIP/SIP systems.
CIP and SIP systems must be constantly evolving and updating. For the continuous improvement of systems, new regulations, new technologies and anything else that can improve the efficiency and effectiveness of the process must always be taken into account.
Some of these improvements that we can mention, by way of example, are:
Optimisation [6]:
- Reuse of rinse water.
- Reduction of times thanks to temperature and concentration adjustments.
- Energy efficiency approaches.
Simulation and digital twin [7]:
The incorporation of simulation technologies, such as digital twin models and AI-based tools, allows for:
- Validate the system design before building it.
- Simulate different cleaning scenarios.
- Detect bottlenecks and opportunities for improvement.
- Reduce physical testing costs.
CIP/SIP systems: validate, control, improve.
In order to implement an effective CIP/SIP system, it is extremely important to involve different internal and external experts in the design and validation of the solution. For this reason, carrying out a HACCP is highly recommended.
All the key points identified are interrelated. Therefore, a solution cannot be proposed without taking into account its constraints and interdependencies.
will be difficult to achieve the required levels of cleaning, disinfection and sanitisation. Therefore, the use of riboflavins with ultraviolet light and sampling for cfu counting should be considered.
An installation may appear to be correct at first glance, but only validation can demonstrate whether it cleans, disinfects and sanitises to the required level. As Steve Jobs said in another context, but completely applicable to industrial hygienic design: “Design is not just how it looks. Design is how it works.”
If you need advice on integrating CIP and SIP systems or designing bagging equipment with advanced hygiene criteria, TMI’s engineering team can help you define the most efficient and safest solution for your process. Contact us.
Juanjo Gónzalez Toledano Director of Engineering, TMI
References:
- Handbook of Hygiene Control in the Food Industry, Edited by: H.l.m. Lelieveld, M.a. Mostert and J. Holah
- Cleaning-in-Place and Sanitization
https://www.sciencedirect.com/science/article/abs/pii/B9780081006238000335
- Hygiene in Food Processing, Editors: H.L.M. Lelieveld, John Holah, David Napper
https://www.sciencedirect.com/book/9780857094292/hygiene-in-food-processing
- HACCP Principles & Application Guidelines
- EHEDG, European Hygienic Engineering& Design Group
- Optimisation of cleaning-in-place systems
https://www.clustercollaboration.eu/content/optimisation-cleaning-place-systems
- Intelligent clean-in-place (CIP) system in beverage (healthy water) cleaner production
https://www.sciencedirect.com/science/article/abs/pii/S0956713524005942
- Hygienic Design and How We Apply It to Bagging Machinery