Chr. Hansen scientist spearheads development of new international standard for counting bacteria

Under the project leadership of Dr Sandra Casani, Principal Quality Scientist, Chr. Hansen, a new joint Standard (ISO 19344/IDF 232) has just been released to provide a method for the quantification of lactic acid bacteria (LAB) by flow cytometry in fermented products, starter cultures, and probiotics used in dairy products.

The project relied on the participation of producers and users of LAB as well as experts and users of flow cytometry from both industry and academia.

Front runner
Flow cytometry is a fast and reliable method for assessing the quality of cultures, as well as an important tool for optimizing production processes and stability assessment during shelf-life. Front runner Chr. Hansen implemented its first flow cytometer, which is able to determine the proportion of active cells and/or total units, in 2005.

“Standardization is essential as the new methodology is met with skepticism versus the traditional way of counting bacteria, known as CFU (colony forming units). The new official standard for flow cytometry provides a blue stamp of its validity, speeds up quality control and facilitates trade of probiotics and starter cultures,” says Sandra Casani.

Optimal and harmonized procedures
Dr Harrie van den Bijgaart, chair of the IDF Methods Standards Steering Group and Chair of the ISO Technical Committee on Milk and Milk Products adds:

“Joint standards such as this one are important to avoid duplication of work and ensure optimal and harmonized procedures in analysis and sampling of milk and milk products around the globe. They also provide safeguards to the equivalence of testing results, whereas the availability of these well-respected joint standards also limits the required in-house validation efforts of the instrument users. The collaboration between the International Dairy Federation and ISO is key in achieving this.”