Bactericidal Efficacy and Mechanisms of Non-Electrolytic Slightly Acidic Hypochlorous Water on Pseudomonas fragi and Pseudomonas fluorescens

Qianru Chen; Yanfang Zhou; Xueyan Yun; Namula Zhao; Hongyu Bu; Tungalag Dong

doi:10.3390/foods12213980

Bactericidal Efficacy and Mechanisms of Non-Electrolytic Slightly Acidic Hypochlorous Water on Pseudomonas fragi and Pseudomonas fluorescens

Foods. 2023 Oct 31;12(21):3980. doi: 10.3390/foods12213980.

Authors

Qianru Chen¹, Yanfang Zhou¹, Xueyan Yun¹, Namula Zhao², Hongyu Bu³, Tungalag Dong¹

Affiliations

¹ College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China.
² Shanghai Wanlay Environmental Technology Co., Ltd., Shanghai 200129, China.
³ Inner Mongolia Institute for Drug Control, West Taoli Street, Hohhot 010020, China.

Abstract

Chilled pork is frequently contaminated with Pseudomonas fragi and Pseudomonas fluorescens. In this study, the bactericidal efficacy and mechanisms of non-electrolytic slightly acidic hypochlorous water (NE-SAHW) against two strains of these two species were evaluated. The results showed that the antibacterial efficacy of NE-SAHW was positively correlated with the concentration level of NE-SAHW and negatively correlated with the initial populations of the strains. The strains of small populations were completely inhibited when provided with each level of NE-SAHW. The killed cells of P. fragi were 0.94, 1.39, 4.02, and 5.60 log10 CFU/mL, respectively, and of P. fluorescens they were 1.21, 1.52, 4.14, and 5.74 log10 CFU/mL, respectively, when the initial populations of the strains were at high levels (about 7 log10 CFU/mL). Both strains were completely killed within 12 s with the available chlorine concentration (ACC) of 50 mg/L of NE-SAHW. Morphological changes in both cells were observed by using a Scanning Electron Microscope (SEM) and it was discovered that the cell membranes were damaged, which led to the leakage of the intracellular substances, including K+, nucleic acid, and protein. In terms of the Fourier Transform Infrared Spectroscopy (FTIR) results, NE-SAHW destroyed the structures of membrane proteins and cell structure proteins, and influenced the composition of polysaccharides. The bacteria were definitely dead after treatment by NE-SAHW compared to the control according to the results of flow cytometry. These results demonstrated the potential bactericidal property of NE-SAHW when applied to the meat and other food sterilization industries.

Keywords: Pseudomonas fluorescens; Pseudomonas fragi; bactericidal efficacy; mechanisms; non-electrolytic slightly acidic hypochlorous water.

Grants and funding

This research was funded by “Research on the application effect of non electrolytic slightly acidic hypochlorite water on the preservation of fresh food (RH1900007172)”; Expert Workstation of Shanghai; Development Project of Inner Mongolia Youth Science and Technology Talent (NMGIRT2310).