Fig. (3) Effect of assay temperature on H₂O₂ sensitivity (Zone of inhibition diameter) for E. coli, Streptococcus lactis (SL), and S. marcescens strains SM-01, SM-02, SM-06 (all cultured at 30°C) and SM wild type cultured at either 28°C (SM-R) or 37°C (SM-W) before exposure to 10µl H₂O₂. Agar plates + H₂O₂-impregnated disks were incubated for 24h at 28°C or 37°C. Incubation at pigment-producing temperature (28°C) slightly increased SM resistance to H₂O₂ exposure, whereas E. coli, catalase-lacking Streptococcus lactis (SL), and the oxyR mutant of Serratia (SM-06) are more sensitive (P < 0.05) at this temperature. * significantly different (28°C vs 37°C).