Acid Resistance and Verocytotoxin Productivity of Enterohemorrhagic Escherichia coli O157:H7 Exposed to Microwave
Article first published online: 2 JUN 2011
© 2011 Institute of Food Technologists®
Journal of Food Science
Volume 76, Issue 6, pages M445–M449, August 2011
How to Cite
Tsuji, M. and Yokoigawa, K. (2011), Acid Resistance and Verocytotoxin Productivity of Enterohemorrhagic Escherichia coli O157:H7 Exposed to Microwave. Journal of Food Science, 76: M445–M449. doi: 10.1111/j.1750-3841.2011.02225.x
- Issue published online: 5 AUG 2011
- Article first published online: 2 JUN 2011
- MS 20110109 Submitted 1/26/2011, accepted 4/7/2011.
- acid resistance;
- Escherichia coli O157:H7;
Abstract: We examined the acid resistance and verocytotoxin (VT) productivity of enterohemorrhagic Escherichia coli O157:H7 irradiated by microwave with a domestic microwave oven and a commercial microwave radiator equipped with a thermo-regulator. When the cell suspension (5 mL) chilled at 0 °C was treated with a domestic microwave oven at weak power (2.45 GHz, 100 W) for 60 s, the living cell number was reduced by 2 orders (final temperature, about 65 °C). The surviving cells showed lower acid resistance and VT productivity than nonirradiated cells. To examine the nonthermal effect of microwave on acid resistance and VT productivity, the cells in Luria-Bertani medium were intermittently irradiated to keep the culture temperature at 37 °C with the microwave radiator (2.45 GHz, 0.6 W/mL). The intermittent radiation slightly reduced the acid resistance, but clearly suppressed the VT productivity. Microwave oven is probably useful for reducing not only the living cell number but also the acid resistance and VT productivity of EHEC O157:H7.