How to qualify a freeze drying plant for food

To ensure security in food production, high requirements from the food sector must be met. Often, a cabled system is currently required to provide proof of adherence to these requirements. When using these systems, Excel lists for complex calculations are frequently used as standard-compliant documentation.

The testo 191 HACCP data logger system is the intelligent solution for the monitoring and documentation of the temperature curve in freeze-drying processes. The smart all-in-one solution, comprising hardware, software, and service, enables you to monitor production processes more efficiently and optimize them sustainably.

This means you reliably adhere to quality standards and save time and money.

The challenge

The objective of the food freeze-drying process is to prolong the shelf life of products such as fruits or instant coffee as well as to make them easier to transport and store, by withdrawing water. To ensure that the prescribed targets are met, the production plants must be regularly qualified according to strict HACCP guidelines.

1. Positioning measurement technology in the plant

The temperature sensors must be stably positioned on the cooling/heating plates in the freeze-drying plant with homemade additional weights. The correct set-up in an average freeze-drying plant with 40 measurement points can take several hours.

2. Evaluation of the measurement values

Several hundred A4 pages of recorded measurement values are not unusual in this kind of measurement, representing a considerable challenge in terms of time for the staff member evaluating the measurement data. Since the measurement data must be completely checked and prepared as tables and graphs, it is almost impossible to process them quickly using standard programmes.

3. Image documentation

To qualify a freeze-drying plant, the measurement setup must be documented with images. This is necessary to be able to reproduce the exact positioning of the temperature sensors during the measurement. Since there are 40 or more measurement points, image documentation of this kind can sometimes be a matter of several hours.

4. Reporting

The requirements placed on the contents of a qualification report are very high, and often present companies with a great challenge. These reports must contain tables, graphs, information on measurement technology, image documentation, and much more. To present this collated information clearly in a report, several programmes are often needed, which is very time-consuming for the processing staff member.

The solution

The testo 191 HACCP data logger system allows the highly efficient qualification of a freeze-drying plant. The system consists of robust, durable, and reliable HACCP data loggers in four temperature and one pressure version; a multifunction case, which serves the programming and readout of the loggers as well as their storage and safe transport; and the unique testo 191 Professional software which enables full, audit-relevant documentation with just the click of a mouse button.

And the best part is there is no effort to
assemble the documentation... because
it can be simply created with a mouse click.

In the development of the testo 191 Professional software, special attention was paid to intuitive operation. The user is guided safely step by step through the qualification process and receives warnings at critical points. The software is therefore equally suitable for experts and beginners.

Using the professional software, up to 8 data loggers (which can be time or temperature-controlled) are programmed, and after the measurement procedure also read out, via a connection cable between the multifunction case and the laptop/computer.

In the context of the data analysis, the calculations for the holding phases are automatically carried out and checked against the defined acceptance criteria. In addition to this, the software enables fast and easy creation of image documentation.

Overview of advantages

• Large measurement data memory

• Fast and reliable overview of the measurement results

• Less effort and lower error potential

• No data export to other systems is needed

• 1-click report

• Integration of up to 254 measurement points into the software possible in a validation process


For more information contact:

Testo South Africa (Pty) Ltd
1 Glen Eagles Office Park
Cnr. Braambos & Monument Rd.
Glen Marais 1619
Kempton Park, South Africa 

T: +27 11 380 8060


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