The inhibitory activity of reuterin stock solutionwas determined by using the modified assay of using E. coli K12
as indicator strain. Reuterin aqueous solutionwas serially diluted in sterile water and 150 ml were added to microtiter plate wells. Overnight culture of test strain was diluted to approximately 104 CFU/g in double strength Tryptic Soy Broth (TSB, Biolife) and 150 ml volumes were dispensed to each well. Distilled water without reuterin was used as negative control. Plates were incubated at 37 C and the absorbance was read during 24 h using a Multiskan Spectrum microplate reader (Multiskan Spectrum, Thermo Labsystems, Finland) at a wavelength of 600 nm. Reuterin arbitrary units (AU) were defined as the reciprocal of the highest two-fold dilution that did not allow the growth of the indicator strain. Three independent experiments were conducted and three replicates per reuterin concentration were analyzed.