ABSTRACT
The objective of this study was to investigate the possibility of using low-amperage electrical treatment (LAET) as a selective bacteriocide. Mixtures containing Escherichia coli, Staphylococcus aureus, and Vibrio parahaemolyticus were treated with different electric current intensities and for different times. The results showed that at 263 mA, treating bacteria for 100 ms eliminated all V. parahaemolyticus colonies. Although LAET reduced the populations of the three microorganisms, V. parahaemolyticus was more injured by LAET than S. aureus and E. coli when treated at the same processing conditions.
Subject(s)
Electricity , Sterilization/methods , Vibrio parahaemolyticus/physiology , Colony Count, Microbial , Escherichia coli/physiology , Escherichia coli/ultrastructure , Food Industry , Microscopy, Electron, Scanning , Staphylococcus aureus/physiology , Staphylococcus aureus/ultrastructure , Time Factors , Vibrio parahaemolyticus/ultrastructureABSTRACT
The inactivating efficiency of alternating high-voltage pulsed (AHVP) current was investigated in brine (20 w/v% NaCl) and saline (0.9 w/v% NaCl) inoculated with 1x 10(7) cells/ml of Listeria monocytogenes. AHVP current at 12 V with 1 pulse completely inactivated L. monocytogenes in brine within 3 ms, while the bacteria in saline were fully inactivated by 10-pulsed electric treatment at 12 V within the same time. Electron microscopic observation demonstrated substantial structural damage of electrically treated L. monocytogenes in brine. These results suggest that AHVP treatment would be effective for the rapid and complete inactivation of L. monocytogenes in brine or saline solution.
Subject(s)
Food Microbiology , Food Preservation/methods , Listeria monocytogenes/growth & development , Microbial Viability , Sodium Chloride/pharmacology , Electricity , Listeria monocytogenes/drug effects , Microbial Viability/drug effectsABSTRACT
Vibrio parahaemolyticus, the cause of gastroenteritis in humans, was inactivated by alternating low-amperage electricity. In this study, the application of alternating low-amperage electric treatment to effluent seawater was investigated for the large-scale disinfection of seawater. This method was able to overcome the problem of chlorine generation that results from treatment with continuous direct current. In conclusion, our results showed that alternating-current treatment inactivates V. parahaemolyticus in effluent seawater while minimizing the generation of chlorine and that this alternating-current treatment is therefore suitable for practical industrial applications.
Subject(s)
Seawater/microbiology , Sterilization/methods , Vibrio parahaemolyticus/isolation & purification , Animals , Aquaculture , Electricity , Humans , Marine Biology , Sterilization/instrumentation , Vibrio parahaemolyticus/pathogenicityABSTRACT
Seawater used in mariculture has been suspected of being a potential source of infection. In this study, the lethal effects of low-amperage electric treatment on microorganisms were examined in natural seawater and in seawater inoculated with Vibrio parahaemolyticus. In both cases, bacteria including V. parahaemolyticus in seawater were completely eliminated in 100 ms by a 0.5-A, 12-V direct current. Electron microscopic investigation of the electrically treated bacteria revealed substantial structural damage at the cellular level. In conclusion, our results indicate that low-amperage electric treatment is effective for rapid inactivation of microorganisms in seawater.
