Antibacterial Activity Screening of Products

In a 96-well microplate, the following were added to each well: 75 µL fresh nutrient broth, 50 µL test product, 25 µL E. coli broth culture at 0.5 OD, adapted from Kalyoussef et al.^{21 (link)}. Each of the seven E. coli strains were tested against the five products and four controls (Table 1). Corresponding control wells, which served as blanks in calculations of optical density at 600 nm (OD₆₀₀), were created for every test condition containing 25 µL of nutrient broth medium instead of 25 µL of bacterial broth culture. Plates were incubated at 37 °C with agitation for 6 hours. OD₆₀₀ measurements were taken at every 2 hours with a Biotek Gen5 plate reader (Burlington, VT).