A clean flow pasteurizer: the basis for safe and consistent dairy production
A properly cleaned flow pasteurizer is essential in the production of dairy products. Milk naturally contains fats, proteins, lactose and minerals, and during heating and processing it leaves residues in pipes and equipment that are more difficult to remove. Without proper cleaning, taste deviations, quality problems or even downtime can occur – for example due to a blockage of the pasteurizer. Thorough cleaning prevents these risks. In this article we explain how a flow pasteurizer works, where contamination occurs and which cleaning steps are required for a hygienic and efficient production process.
Hygienic process areaThis is how a flow-through pasteurizer works
- A continuous flow pasteurizer heats milk in a controlled manner and then cools it immediately – without interrupting the flow of milk. The purpose of heating is to eliminate harmful microorganisms and extend shelf life, with as little loss of taste and nutritional value as possible.The process takes place in three phases:A continuous flow pasteurizer heats milk in a controlled manner and then cools it immediately – without interrupting the flow of milk. The purpose of heating is to eliminate harmful microorganisms and extend shelf life, with as little loss of taste and nutritional value as possible.The process takes place in three phases:
- Regeneration
The incoming raw milk is preheated by means of the plate heat exchanger. When the pasteurizer is in operation, a regeneration process is used, whereby up to 90% of the heat used is recovered.
- Pasteurization
After preheating, the milk is further passed through a heat exchanger with hot water to the set pasteurization temperature. This kills most germs, such as bacteria. - Cooling
The milk is cooled down by means of the plate heat exchanger. This uses the cold raw milk that comes in (regeneration process). This prepares the system for the next flow of milk.This efficient, closed process makes a flow pasteurizer ideal for medium to large milk processors that strive for consistent quality and high food safety.
Why is a flow-through pasteurizer difficult to clean?
Cleaning a flow-through pasteurizer has specific challenges. Due to the structure and operation of the system, certain bottlenecks can arise:
- Stubborn contamination due to heating
During pasteurization, the milk is heated, which causes proteins, fats and minerals to adhere to the walls. This contamination is more difficult to remove and therefore to clean.
- Small channels in the heat exchanger
The narrow passages provide a lot of surface area for dirt to settle. This allows dirt to build up quickly.
- Low fluid velocities
The relatively low flow rate of the milk in the small channels ensures less natural friction (mechanical action), making it more difficult for contaminants to come loose.
- No direct visual control
Unlike a stand pasteurizer, it is not easy to see whether pipes and exchangers are really clean.
Validation: essential for reliable pasteurization
The validation step is essential to ensure that the flow-through pasteurizer functions correctly. During validation, it is checked whether the system achieves the correct time-temperature combination under real conditions to effectively eliminate harmful microorganisms.
Key validation points:
- Verification of temperature, time and flow rate.
- Check for deviations that could affect pasteurization.
- Documentation and registration for food safety assurance (for example for HACCP).
In short: without valid pasteurization no guaranteed food safety.
Step by step: this is how CIP cleaning of a flow pasteurizer proceeds
A good CIP cleaning consists of several steps that are precisely aligned with the production planning. This structured approach ensures thorough cleaning of the installation, with minimal downtime.
For the production
- Thermal disinfection (heat cleaning)
This step ensures that the system is microbiologically clean before production starts. The flow-through pasteurizer is heated with hot water or steam, so that any microorganisms present are eliminated.
After production
- Pre-rinse
The first rinse step ensures that most milk residues are flushed out of the pipes and equipment. Less contamination makes the cleaning agent work more effectively. - Alkaline cleaning
A strong alkaline cleaning agent, such as SynQ Blue CIP Extra, dissolves proteins and fats — even when the level of contamination is high. - Rinsing
Rinsing with water rinses away lye residues and dirt residues. - Periodic top-up (weekly or based on degree of pollution)
- Acidic cleaning
An acidic cleaning agent such as SynQ Red CIP removes mineral deposits (such as milkstone and limescale) that have built up during production and heating. - Rinsing
A rinse step with water also follows after acidic cleaning to remove dirt residues and the acid.
When is the cleaning in order?
You can recognize an effective CIP cleaning of the flow pasteurizer by:
Pre-rinsing
The rinsing water is clear without milk residues.
Cleaning
- The operator has confirmed that the correct cleaning agents have been dosed.
- The rinse water is clear without milk residue.
- The lye water is no longer cloudy or discoloured.
- The pH values ​​of lye and rinse water are within the expected values. This can be checked with a pH strip or pH meter.
Rinsing
The rinse water is clear without lye residues.
It is important to ensure that the entire installation, including pipes, has been cleaned. In addition, the set cleaning time and temperature must have been achieved and recorded. Do not only check digitally (for example via sensors or pH meters), but always use your eyes as well. Visual control remains a valuable additional control tool. In short: measure, record and look.
Advice and support
Would you like to know more about CIP cleaning or receive a cleaning protocol for the flow-through pasteurizer? Are you considering purchasing a flow-through pasteurizer? Please contact van C. van ‘t Riet Zuiveltechnologie.
