Decontamination of lettuce using acidic electrolyzed water

Area of Science:

• Food safety
• Microbiology
• Water treatment technologies

Background:

• Ensuring the microbial safety of fresh produce like lettuce is crucial for public health.
• Traditional disinfectants like sodium hypochlorite (NaOCl) can have limitations.
• Alternative disinfection methods are being explored to improve efficacy and safety.

Purpose of the Study:

• To compare the disinfectant efficacy of acidic electrolyzed water (AcEW), ozonated water, and NaOCl on lettuce.
• To investigate the effectiveness of these agents in reducing microbial load on lettuce surfaces.
• To assess the impact of these treatments on lettuce microstructure.

Main Methods:

• Lettuce samples were treated with AcEW, ozonated water, and NaOCl solution.
• Microbial reduction was quantified by counting viable aerobes (log CFU/g).
• Swabbing tests and scanning electron microscopy (SEM) were used to evaluate surface decontamination and structural integrity.

Main Results:

• AcEW and NaOCl significantly reduced viable aerobes by 2 log CFU/g within 10 minutes.
• AcEW demonstrated a statistically significant higher disinfectant effect than ozonated water.
• All tested agents removed aerobic bacteria, coliforms, molds, and yeasts, but bacterial spores and biofilms persisted; lettuce structure remained undamaged.

Conclusions:

• AcEW is an effective disinfectant for controlling microorganisms on fresh lettuce surfaces.
• While effective against many microbes, AcEW and other tested agents did not eliminate bacterial spores or all biofilms.
• The surface structure of lettuce was not compromised by any of the disinfection treatments.