Impact of electrolyzed water treatment on bacterial communities in food washing processes

Abstract

Electrolyzed water is expected to have a sterilizing effect on bacteria and viruses, which makes it useful for hygiene management, such as cleaning dishes or medical equipment. Electrolyzed water treatment may affect the cellular structure of microbes, leading to DNA leakage or degradation. Here, we conducted a next-generation sequencing (NGS) analysis of bacterial diversity in washing solution to elucidate the impact of cleaning food surfaces with electrolyzed water. Modified primers were used to evaluate the differences between the existing primers used to obtain NGS sequences and through statistical analysis. The NGS reads obtained using the modified primers tended to reveal more Enterobacteriaceae sequences, and fewer mitochondrial sequences than did those obtained with conventional primers. An UniFrac distance analysis and Nonmetric multidimensional scaling (NMDS) revealed that the results obtained with the modified primer set made the differences between samples more distinct. Real-time polymerase chain reaction (PCR) using the template DNA obtained from an electrolyzed water or sodium hypochlorite solution wash revealed that some of the DNA could not be amplified using PCR of the 16S rRNA genes suggesting that the DNA fragmentation had occurred due to the electrolyzed water treatment. Our results revealed that the bacterial species removed from the food surfaces varied depending on the washing treatment. Electrolyzed water treatment may be advantageous for removing Enterobacteriaceae from leafy vegetables.