β-Propiolactone exhibited a bactericidal effect on Lactobacillus casei. β-Propiolactone inhibited the synthesis of DNA under conditions which allowed the synthesis of RNA and protein. β-Propiolactone inactivated free phage J1. The inactivation rate of phage by β-propiolactone depended on pH and temperature. Almost all of metal cations protected the phage against the effect of β-propiolactone, whereas Fe²⁺ enhanced the inactivation rate of phage by β-propiolactone. β-Propiolactone reacted with phage DNA to cause single-strand scissions in the DNA, thus resulting in phage inactivation.
β-Propiolactone hardly affected the adsorption of phage and injection of phage DNA, but inhibited the intracellular growth of the phage. β-Propiolactone blocked the synthesis of phage DNA, structural protein of the phage and phage endolysin. β-Propiolactone added later in the latent period did not inhibit growth of the phage. A primary and major action of β-propiolactone seems to be its reaction with the injected DNA, thus resulting in the prevention of DNA replication.
The results are discussed in relation to the control of phages in the dairy fermentations.