4.2. Selection of Resistant Strains in Organic Acid Using Disk Diffusion Method

To select the strains with the highest resistant profile to be used in the inactivation modeling, a disk diffusion assay for organic acids was performed. Acetic, lactic, and citric acids were standardized for 4096 µg/mL concentrations. Each strain was transferred to Müller-Hinton 2 broth (MH; Himedia^®, Mumbai, India) and incubated between 2 and 4 h up to 0.5 MacFarland scale [58]. The assay was carried out according to the Kirk Bauer disk-diffusion test [59]. Briefly, the strains were streaked on Müller-Hinton 2 agar (MH; Himedia^®, India) and diffusion disks (LB; Laborclin^®, São Paulo, Brazil) with 10 µL of each organic acid were included in the diffusion disks. After the incubation period of 24 h at 37 ± 0.1 °C, the halos were measured.