1) Temperature changes during current application were monitored at
several locations inside the heating cell. Temperature increase was
the slowest in the upper part of the cell near the electrode. Therefore,
this locationwas selected as the temperaturemeasurement location.
2) There was a high correlation between electrical conductivity
during current application and measured temperature (y = 4E-
05x2 + 0.0010x + 0.3690 with a contribution rate of R2 = 0.98).
Thus,we demonstrated that sample temperature could be estimated
with a certain level of confidence based on current and voltage
values.
3) A sterilization test was conducted on the prepared ohmically heated
samples. The samples conformed to the constant-temperature test
and the microbiological test for retort food stipulated under the
Food Sanitation Act. Therefore, it was suggested that the shelf life
of the ohmically heated samples was almost the same as that of
the retort-heated samples.
4) Temperature changes during heating were compared for the two
heating methods. Temperature increase was quicker under retort
heating immediately after the start of heating. However, both
sample types reached 70 °C at nearly the same time; thereafter,
temperature increase was quicker under ohmic heating. Thus, it