Abstract: In this paper, the kinetics of destruction of bacteria cells suspended in a solution by microwave irradiation with a microwave oven were studied. The destruction rates at different powers were studied. The results showed that the rate of cell destruction is higher in 900 W than 100 W under the same temperature. The destruction kinetics of S.aureus and E.coli with microwave exposure in the same temperature were also compared. S.aureus has significantly higher D-values (5.05 min at 55 ℃, 2.60 min at 60 ℃ and 1.21 min at 65 ℃) than E.coli (41.7 min at 50 ℃, 4.06 min at 55 ℃, 1.57 min at 60 ℃) respectively microwave energy. When pH is of lower optimum pH, the susceptibility of cells to physical and chemical treatments increases. With the increasing concentration of salt in the solution (8.5 g/L,20 g/L and 40 g/L), the destruction rate of S.aureus is highest at the concentration of 20 g/L at 60 ℃, while the rate of E.coli decreases with the increasing concentration of salt. S.aureus were treated with microwave at different temperature, subsequently interacted with Flou-3/AM respectively. The results showed that the permeability of cell membrane is changed after microwave treatment.

Key words: microwave, sterilization, S.aureus, E.coli, cell membrane permeability