Bacteriophages, viruses that infect bacteria, are a major challenge in the production of fermented foods. They can attack the bacterial starter cultures that drive fermentation, causing failures or inconsistencies in products such as cheese. When a new starter culture is used intensively, phages may adapt quickly and disrupt its activity. Managing phages is therefore essential to ensure reliable and safe food production.
This project supports the development and use of starter cultures by improving knowledge of phage diversity and behavior in real production environments. Phages will be collected and studied, together with their interactions with bacterial strains, to design strategies that reduce their impact while respecting the practical constraints of food processing.
The focus is on mesophilic cheese starter cultures, increasingly important in Switzerland but particularly vulnerable to phages. Thermophilic cultures, used in traditional Swiss cheeses, will also be monitored, as they are not fully spared. Depending on opportunities, phages from fermented plant products may also be explored, paving the way for future research in this emerging sector.