Indigo carmine, a food additive, inactivates DNA phages and protects bacterial cultures (Applied Microbiology and Biotechnology)

Indigo carmine, an FDA-approved food additive, selectively inactivated DNA phages (P001, T4, T1, T7, lambda) but not the RNA phage MS2, by binding double-stranded DNA and causing genome ejection from the capsid; under optimal conditions (50 C, 220 rpm) it gave up to a 7-log reduction in phage titer. It also protected E. coli cultures from phage-induced lysis, which the authors propose as an antiphage agent for industrial bioprocesses.