Assessment of low-energy electron beam irradiation for effective surface microbial decontamination of fresh lettuce (Lactuca sativa L.) leaves

Microbial contamination in fresh produce, particularly leafy greens such as lettuce and spinach, constitutes a significant public health concern due to infections caused by enteropathogens. Therefore, low-energy electron beam (LEEB) irradiation has been introduced to ensure microbial decontamination, analogous to conventional irradiation applications. This study examines the efficacy of LEEB irradiation in reducing bacterial contamination in lettuce (Lactuca sativa L.) and determines the radiation sensitivity of target microorganisms through D₁₀ values compares it with the gamma-ray treatment. Hydroponically cultivated lettuce samples were inoculated with Escherichia coli, Salmonella Enteritidis, Listeria monocytogenes, and E. coli O157:H7. Following LEEB treatment, the D₁₀ values of four pathogens were calculated between 0.371, and 0.737 kGy, whereas gamma irradiation resulted in lower values of 0.262–0.327 kGy. These results suggest that LEEB doses in the range of approximately 1.7–3 kGy may be sufficient to achieve an average 4-log reduction in pathogens. Additionally, the effects of LEEB irradiation on the physicochemical properties of lettuce were evaluated immediately after irradiation at doses of 1, 3, and 5 kGy. While no statistically significant differences were observed in color and total vitamin C (p > 0.05), bioactive compound levels increased at higher doses (p < 0.05). Fourier Transform Infrared (FT-IR) spectroscopy confirmed minimal structural alterations. These findings suggest that LEEB irradiation effectively decontaminates lettuce while maintaining its physicochemical integrity and enhancing its bioactive properties, presenting a promising and very important approach for improving fresh produce safety.