Sequential application of peracetic acid and UV irradiation (PAAUV/PAA) for improved bacterial inactivation in fresh-cut produce wash water

Authors: ZHANG, TIANQI - Georgia Institute Of Technology; Luo, Yaguang - Sunny; Zhou, Bin; TENG, ZI - University Of Maryland; HUANG, CHING-HUA - Georgia Institute Of Technology; Nou, Xiangwu

Submitted to: ACS Environmental Science & Technology Water
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2022
Publication Date: 7/8/2022
Citation: Zhang, T., Luo, Y., Zhou, B., Teng, Z., Huang, C., Nou, X. 2022. Sequential application of peracetic acid and UV irradiation (PAAUV/PAA) for improved bacterial inactivation in fresh-cut produce wash water. ACS Environmental Science & Technology Water. 2(7):1247-1253. https://doi.org/10.1021/acsestwater.2c00087.
DOI: https://doi.org/10.1021/acsestwater.2c00087

Interpretive Summary: Washing is essential for ensuring the quality and safety of fresh-cut produce. Currently, chlorine-based sanitizers are widely used by fresh produce processors to control microbial contamination. However, chlorine is unstable during produce processing and converted into harmful disinfection byproducts (DBPs). Thus, a novel sanitization method was developed to address this issue. Using a combination of peracetic acid (PAA) and mild ultraviolet (UV), a significant reduction in microbial count with negligible DBP was achieved. This study provides an effective, safe, and energy-efficient approach to improving microbial safety and quality at fresh produce processing facilities.

Technical Abstract: Chlorine-based sanitizers are widely used in fresh-cut vegetable processing to reduce water mediated microbial cross-contamination. However, the formation of halogenated disinfection byproducts (DBPs) in water and on produce necessitates the search for alternative disinfectants. This study investigated peracetic acid (PAA), UV irradiation (UV), and the combination of PAA and UV concurrently (UV/PAA) or sequentially (PAA-UV/PAA) as novel disinfection strategies to treat fresh-cut produce wash water using E. coli as a surrogate of pathogenic bacterium. Evaluating the disinfection kinetics under PAA, UV, and UV/PAA revealed that the reactive radicals generated under UV/PAA did not effectively contribute to E. coli inactivation in the presence of high organic content of produce wash water. Light shading from the high organic content hindered E. coli inactivation under UV or UV/PAA. In contrast, the PAA-UV/PAA process was negligibly impacted due to the advantage of PAA diffusion into bacterial cells. Furthermore, PAA-UV/PAA is more energy efficient compared to UV/PAA. To achieve 1-log E. coli reduction, 0.76-1.40, 1.94-2.57, and 2.77-5.32 J·L-1 UV energy was required for PAA-UV/PAA, UV/PAA, and UV, respectively. This study suggests the sequential application of PAA-UV/PAA as a favorable alternative to chlorine in fresh-cut produce wash water disinfection, owing to high disinfection efficacy, superior performance stability and low DBP risk.