Inactivation of Saccharomyces cerevisiae in solution by low-amperage electric treatment.
OBJECTIVE
The objectives of this study were to investigate the potential application of a low-amperage direct electric current as a non-thermal process for inactivation of Saccharomyces cerevisiae.


RESULTS
Electric current was generated using a direct current power supply connected to a traditional electrochemical cell with two platinum electrodes immersed in conducting solution containing a population of S. cerevisiae. This treatment provoked inactivation of the yeast cells. The microbial destruction illustrated by D-values calculated from survival curves was shown to be proportional to the current amperage (i) (D varies from 1547 min to 140 min when i varies from 0.1 to 1 A, respectively). The efficacy of the treatment was shown to be better at pH < 7. Statistical analysis showed no significant effect (P > 0.05) of ionic strength on yeast lethality induced by electrolysis.


CONCLUSIONS
The lethal effect of the electric treatment on S. cerevisiae in phosphate buffer was shown to be due to neither ohmic heating nor toxic hydrogen peroxide. A synergistic effect of temperature and electrolysis was observed when the temperature became lethal for the yeast.


CONCLUSIONS
The method described for yeast lethality induced by electrolysis has potential for soft sterilization, particularly when combined with the synergistic effect of moderate heat.
Guillou
S
S
Laboratoire d'Analyse Isotopique et Electrochimique de Métabolismes, Université de Nantes, Faculté des Sciences et des Techniques, Nantes, France.
El Murr
N
N
D002021:Buffers; D004560:Electricity; D004572:Electrolysis; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D013242:Sterilization / Q000379:methods*; D013696:Temperature
D002021:Buffers