3.6.2. Disc Diffusion Technique

A loop full of bacteria, incubated for 24 h in a nutrient agar slant of each bacterial species, was inoculated in a test tube containing 5 mL of tryptic soy broth. Broth culture was incubated at 37 °C for 4 h until it achieved turbidity of 0.5 McFarland BaSO₄ standard (10⁸ cfu mL⁻¹). The sensitivity tests of mandarin peel extract, hesperidin, and sodium nitrite were determined with different bacterial strains using the disc diffusion method by the Kirby–Bauer technique [50,51]. DMSO represented the negative control. After that, inoculated plates were incubated at 37 °C for 24 h. At the end of the incubation period, inhibition zones were expressed as the diameter of clear inhibition zone including the diameter of the paper disc.