Bacterial eradication by a low-energy pulsed electron beam generator

Area of Science:

• Industrial Microbiology
• Radiation Physics
• Biotechnology

Background:

• Low-energy electron beams (LEEB) are used for industrial sterilization but suffer from low dose rates, causing product degradation and limiting throughput.
• Existing LEEB technology faces challenges in achieving high-throughput sterilization due to low dose rates and energy limitations.

Purpose of the Study:

• To develop and evaluate a low-energy pulsed electron beam generator (LEPEB) for efficient and high-throughput sterilization.
• To investigate the inactivation efficacy and underlying mechanisms of LEPEB against bacterial spores and vegetative cells.

Main Methods:

• Irradiation of Bacillus pumilus vegetative cells and spores using a 250 keV LEPEB system with a 100 Hz pulse repetition frequency and 10 ns pulse duration.
• Assessment of bacterial inactivation rates, morphological/structural integrity, cell wall hydrophobicity, and DNA damage (single- and double-strand breaks, pyrimidine dimers).

Main Results:

• Achieved >6 log10 inactivation of vegetative bacteria in 20 ms (2 pulses) and spores in 80 ms (8 pulses).
• No morphological or structural defects were observed in the treated cells.
• Observed decreased cell wall hydrophobicity in vegetative cells and significant DNA damage, indicating cell death mechanisms.

Conclusions:

• The LEPEB system provides a high dose rate with nanosecond pulse delivery, enabling effective and high-throughput bacterial eradication.
• This technology is suitable for direct integration into production lines for diverse industrial sterilization applications.
• LEPEB offers a promising alternative to conventional sterilization methods, addressing limitations of traditional LEEB systems.