Effect of High Hydrostatic Pressure on Aeromonas hydrophila AH 191 Growth in Milk
Version of Record online: 3 AUG 2012
Journal of Food Science © 2012 Institute of Food Technologists® No claim to original US government works
Journal of Food Science
Volume 77, Issue 8, pages M417–M424, August 2012
How to Cite
Durães-Carvalho, R., Souza, A. R., Martins, L. M., Sprogis, A. C. S., Bispo, J. A. C., Bonafe, C. F. S. and Yano, T. (2012), Effect of High Hydrostatic Pressure on Aeromonas hydrophila AH 191 Growth in Milk. Journal of Food Science, 77: M417–M424. doi: 10.1111/j.1750-3841.2012.02819.x
- Issue online: 3 AUG 2012
- Version of Record online: 3 AUG 2012
- MS 20110880 Submitted 7/21/2012, Accepted 5/24/2012.
- Aeromonas hydrophila;
- bacterial inactivation;
- high pressure;
Abstract: Exposure to high pressure is an efficient method of bacterial inactivation that is particularly important for reducing the microbial load present in foods. In this study, we examined the high pressure inactivation of Aeromonas hydrophila AH 191, a virulent strain that produces aerolysin, a cytotoxic, enterotoxic, and hemolytic toxin. High pressure treatment (250 MPa for 30 min at 25 °C in 0.1 M PBS, pH 7.4) of A. hydrophila grown in milk reduced bacterial viability by at least 9 orders of magnitude. Under these conditions, the enterotoxic, hemolytic, and cytotoxic activities of A. hydrophila culture supernatants were unaltered. These results indicate the need for caution in the use of high pressure for food processing since although truly toxigenic bacteria may be inactivated, their toxins may not be, thus posing a risk to human health. At higher pressure (350 MPa) the inactivation of bacteria was much more effective. Scanning electron microscopy showed a significant decrease in the number of bacteria after higher pressurization (350 MPa for 1 h) and transmission electron microscopy showed irregular shaped bacteria, suggestive of important cell wall and membrane damage, and cytoplasm condensation.
Practical Application: High pressure inactivates Aeromonas hydrophila efficiently but is enhanced when combined with moderate temperature (40 °C). The biological activities of toxins from this bacterium are unaltered under these conditions.