Effects of field strength and frequency on inactivation of Clostridium sporogenes PA3679 spores during ohmic heating
Shyam Singh, Mohamed Medhat Ali, Jin Hong Mok, Sudhir K. Sastry
Abstract
The study explored the effects of electric field strength, temperature, and frequency on the inactivation of Clostridium sporogenes PA3679 spores (a surrogate of Clostridium botulinum) within buffer. The experiments were conducted at three different field strengths (30, 40, and 50 V/cm), temperatures (110, 120, and 130 °C), and frequencies (60, 1000, and 5000 Hz). Ohmic heating resulted in significantly greater reduction of C. sporogenes compared to conventional heating. Electric field strength significantly influenced spore inactivation. It was found that lower frequencies led to quicker rates of inactivation. Given that high field strengths have dual benefits of increasing both heating and spore kill rate, the possibility exists to process foods to sterility without a hold. This is expected to result in improved product quality, reduced process times and increased efficiency.