Bacteriophages

Bacteriophages are viruses that infect bacteria. When a lytic phage infects, the bacterium stops making its own DNA, RNA and proteins; the phage hijacks the host’s transcription and translation machinery to build new particles, and once assembled they burst the cell, releasing several hundred progeny phages. Many phages are lysogenic instead: they integrate into host-cell DNA as prophages and lie dormant until conditions trigger the lytic cycle. In dairies, phage attacks on starter cultures cause costly fermentation failures and whey-quality problems, but the same specificity makes phages promising biocontrol agents against foodborne pathogens such as Listeria and Salmonella on foods and surfaces.