Quality control for flour milling

29 November 20227 min reading

The consequences of deviation in the analytical results of a laboratory are numerous and can lead to the emergence of crises within the flour milling industries that can impact consumer health and jeopardize the industries’ economy. Proficiency Testing Schemes (PTS) are crucial for detecting analytical derivatives in laboratories performances, hence is helping with favoring a corrective measure over another. 

Quality control laboratories are key actors of flour milling industries. Flour, as a non-perishable food is one of the common pantry staples and the most basic food ingredient of a consumer. And even if it is technically imperishable, it requires monitoring and controls during the whole process of the production. 

According to the United States’ Centers for Disease Control and Prevention, in July 2019, multiple brands and types of flour on the market may be contaminated with Escherichia coli. All suspected products were recalled because of the risks on the consumer’s life. Thus, when many processed foods as pasta, bread, baked goods are prepared with contaminated flour, the contamination chain can be quickly enlarged. This is why access to safe flour-based products is essential to sustaining human life. As a primary feed, producers and laboratories must pursue specific regulations regarding flour production. 

In this framework, the need of laboratories for efficient quality control of analysis leads them to participate in Proficiency Testing Schemes (PTS) which helps them prevent analytical deviations in performance monitoring; this solution offers tremendous potential to improve the safety and the quality of flour. The evaluation of the reliability of the methods used along in PTS are important elements of laboratory quality assurance. PTS are also the opportunity for laboratories to compare their analytical results with other laboratories; also, the validation of the methods used allow laboratories to acquire reliable, repeatable, and accurate results when using a specific method.  

Quality control tools use to verify specific characteristics in flour such as gluten index, moisture content, protein content, falling number etc. allow the producers to know more about the quality of their flour. 

That is why continually evaluating laboratory performance through participation in proficiency testing remains an effective means of control for improving reliability of results in order to enhance health quality in food. By using PTS as an independent quality control tool, analytical laboratories can verify their testing process to comply with accreditation bodies according to the ISO/IEC 17025 standard. The internal and external quality controls implemented in the laboratories are essential to ensure the validity of the results, the equipment calibration or for development and method validation; PTS perfectly meet these objectives as external quality controls.  The attendance in proficiency testing programs is one standards of the ISO/IEC 17025 standard requirements in order to provide analytical results with reliability.


According to ISO/IEC 17043, a PTS is defined as the evaluation of a laboratory’s testing by means of performance, using interlaboratory comparisons. These are used to monitoring the continuity of laboratory performance. 


The main purpose of interlaboratory comparisons used in PTS is the evaluation of the performance of laboratories for specific tests or measurements and monitoring laboratories’ performance.

In addition, participation in a PTS also enables the laboratory to:

- identification of analytical problems who may be related to inadequate test or measurement procedures, effectiveness of staff training and supervision, or calibration of equipment,

- demonstrate the accuracy of their results to third parties and customers,

- compare the methods used by the laboratories,

- and to validate the uncertainties measurement claimed by the laboratories.


Participation in a PTS follows a classic and simple pattern: after registering the laboratory to the PTS of interest, the laboratory receives the samples according to the defined schedule and carries out the analysis. After the results’ transmission, a statistical treatment is carried out before the report is sent.

The report is provided to the laboratory with several information. Firstly, an overall summary of the results which includes the data of totality of laboratories. The report contains information about the design of the program, samples manufacturing, controls and the raw data including statistical treatment, Secondly, an individual summary of its results with a judgement of its performance by criteria is delivered.

Available programs in the fields of flour milling and grains

In this field, BIPEA offers a wide range of proficiency testing schemes in chemistry and microbiology, with real matrices’ samples. BIPEA offers several proficiency tests depending on different types of analysis, and based on a wide range of real matrices: flours, semolina, grains, wheat, soya…The analysis of these samples must be carried out under routine conditions in terms of the procedures and applied methods.

Chemistry analysis: The flour milling programs are offered as a whole and account for a variety of analytical parameters such as ash content, fat acidity, gluten, falling number, moisture content with flour or semolina matrices.

Microbiological analysis: A program dedicated enumeration of several microorganisms in fresh flour (refrigerated samples) and detection of Salmonella spp.


PTS 02 - Flour: physico-chemical analyses and alveograph: This program brings all together 296 participants from 48 countries around the world for flour analysis according to the following analytical parameters: Ash content, Falling number (Hagberg-Perten), Manual & mechanical gluten, gluten index, Moisture content, Protein content, Amylograph, Ascorbic Acid…

PTS 41 - Flour: Rheofermentometer: With about ten participants worldwide, several analytical criteria are proposed, including: Water volume added, Temperature of the dough, Dough Development, Gaseous release…

PTS 72 - Flour: Mixolab standard protocol: This trial, which brings together 24 participants from 11 countries, invites laboratories to analyze flour according to 2 parameters: Torque, Time and temperature at step C1, C2, C3, C4, C5. 

PT 56 - Microbiology on flours: Around 37 laboratories from more than 20 countries participate in this program. This trial consists of analyzing contaminated flours samples for enumeration of several microorganisms in fresh flour and detection of Salmonella spp.

PTS are reliable quality control tools for flour milling that improve confidence in test results obtained by analytical laboratories. These tools used in the framework of quality control management of a laboratory will allow to give information about the classification and the quality of the flour. 

The consequences of deviation in the analytical results of a laboratory are numerous and can lead to the emergence of crises within the flour milling industries that can impact consumer health and jeopardize the industries’ economy. PTS are crucial for detecting analytical derivatives in laboratories performances, hence is helping with favoring a corrective measure over another. 

The increase in demand from laboratories to take part in PTS proves the interest for laboratories in their quality control approach according to the ISO/IEC 17025 standard requirements. The sustainability for participation in these PTS is a key to helping laboratories to have confidence in their results, in the calibration of their instruments by providing precise reference values and data. Ensuring flour safety is a daily challenge for testing laboratories that are continually seeking to improve efficiency, productivity and profitability.


BIPEA is a non-profit scientific organization created in 1970 and currently offers a wide range of proficiency testing and external reference materials for quality control testing laboratories. ISO 17043 accredited (scope 1-1495 available on and ISO 9001 certified, BIPEA gathers over 2500 testing laboratories from 120 countries. With our experience, we offer a range of services to testing laboratories and manufacturers in various fields such as food, environment, cosmetics and pharmaceuticals. BIPEA’s core activity is to enhance the performance of laboratories and works its position up as a privileged partner of testing laboratories.

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