What is bacteriophage contamination and why is it a concern?

Bacteriophages are viruses that infect bacteria, causing cell lysis (lytic phages) or integrating into host genome (lysogenic phages). In fermentation, phage contamination can devastate production: infected cells lyse, releasing more phages that spread rapidly through the culture. Signs include sudden culture clearing, reduced productivity, and foaming. Sources include: raw materials (dairy, plant-derived), process water, and personnel. Prevention involves: phage-resistant strains, rotation of different strains, strict hygiene, air filtration, and raw material testing. Recovery requires thorough facility decontamination as phages are resistant to many cleaning agents. Phage contamination is a significant concern in dairy and amino acid fermentation industries.