Influence of organic matters on the inactivation efficacy of plasma-activated water against E. coli O157:H7 and S. aureus

Hsiao

et al. 2020

Foods

Eggs are one of the most commonly consumed food items. Currently, chlorine washing is the most common method used to sanitize shell eggs. However, chlorine could react with organic matters to form a potential carcinogen, trihalomethanes, which can have a negative impact on human health. Plasma-activated water (PAW) has been demonstrated to inactivate microorganisms effectively without compromising the sensory qualities of shell eggs. For this study, various amounts (250, 500, 750, or 1000 mL) of PAW were generated by using one or two plasma jet(s) at 60 watts for 20 min with an air flow rate at 6 or 10 standard liters per minute (slm). After being inoculated with 7.0 log CFU Salmonella Enteritidis, one shell egg was placed into PAW for 30, 60, or 90 s with 1 or 2 acting plasma jet(s). When 2 plasma jets were used in a large amount of water (1000 mL), populations of S. Enteritidis were reduced from 7.92 log CFU/egg to 2.84 CFU/egg after 60 s of treatment. In addition, concentrations of ozone, hydrogen peroxide, nitrate, and nitrite in the PAW were correlated with the levels of antibacterial efficacy. The highest concentrations of ozone (1.22 ppm) and nitrate (55.5 ppm) were obtained with a larger water amount and lower air flow rate. High oxidation reduction potential (ORP) and low pH values were obtained with longer activation time, more plasma jet, and a lower air flow rate. Electron paramagnetic resonance (EPR) analyses demonstrated that reactive oxygen species (ROS) were generated in the PAW. The observation under the scanning electron microscope (SEM) revealed that bacterial cells were swollen, or even erupted after treatment with PAW. These results indicate that the bacterial cells lost control of cell permeability after the PAW treatment. This study shows that PAW is effective against S. Enteritidis on shell eggs in a large amount of water. Ozone, nitrate, and ROS could be the main causes for the inactivation of bacterial cells.

Section: Discussionmentioning

confidence: 95%

The Antibacterial Efficacy and Mechanism of Plasma-Activated Water Against Salmonella Enteritidis (ATCC 13076) on Shell Eggs

Hsiao

et al. 2020

Foods

“…This phenomenon was attributed to the proteins in the beef extract media, which tended to scavenge the reactive species generated in the liquid. Xiang et al () investigated the inactivation efficacy of PAW with the presence of two forms of organic matter, namely beef extract and peptone, against E. coli O157:H7 and Staphylococcus aureus . Results showed that either beef extract or peptone significantly reduced the inactivation efficacy compared with PAW, and the reduced inactivation efficacy was in a dose‐dependent manner.…”

Section: Discussionmentioning

confidence: 99%

Influence of various fish constituents on inactivation efficacy of plasma‐activated water

Zhao

Ojha

Burgess

et al. 2020

Int J of Food Sci Tech

Plasma-activated water (PAW) is an effective disinfectant against a wide range of microorganisms, but its effect on food products is limited. This study aimed to investigate the fluid environment on the inactivation efficacy of PAW and its application on fish decontamination. Three organic media (fish gelatin, fish oil and fish homogenate) at 5%, 10% and 20%, and inorganic media of phosphate-buffered saline (PBS) and water were inoculated with Pseudomonas fluorescens at a final concentration of 7 log 10 CFU per mL. The inoculated media were treated by an atmospheric cold plasma jet at 30 kV for 5 min and stored at 4°C for 24 h, during which the inactivation effects were determined at different exposure times. The physicochemical properties of the media were measured. Furthermore, PAW generated for 15 min was applied to P. fluorescens-inoculated fish. The results showed that PAW achieved a complete inactivation immediately after treatment, while there was almost no reduction for plasma-activated PBS even after 24 h. Reduced inactivation efficacy was observed for the organic media except for fish oil, and the inactivation rates were in inverse correlation to the concentrations of organic material. PAW treatment obtained 0.4 log reduction on fish. This study revealed that the fluid environment had a great influence on the inactivation efficacy of PAW, and PAW can be a potential sanitiser for fish decontamination. Factors influencing the inactivation effect of PAW Y.-M. Zhao et al. 2631 Factors influencing the inactivation effect of PAW Y.-M. Zhao et al. Factors influencing the inactivation effect of PAW Y.-M. Zhao et al. 2635 Factors influencing the inactivation effect of PAW Y.-M. Zhao et al.

Comp Rev Food Sci Food Safe

“…The antioxidants present in the food also act as scavengers of reactive species and reduce their bactericidal properties. In a recent study, Xiang, Kang, et al (2019) proved the negative impact of organic matter on the bactericidal properties of PAW in E. coli and S. aureus. They also stressed on the importance of considering the presence of organic matter including food constituents while using PAW for food-related applications.…”

Section: Ntp-liquid Interactions In Foodmentioning

confidence: 99%

“…However, many pathogens are becoming resistant to these conventional sanitizing compounds (Rodríguez‐López, Rodríguez‐Herrera, Vázquez‐Sánchez, & Lopez Cabo, ; Tomat, Balagué, Aquili, Verdini, & Quiberoni, ). Further, the efficiency of these chemical sanitizing agents depends on the availability of free chlorine, wash water quality, microbial load, washing time, and presence of other organic and inorganic matter (Murray et al., ; Xiang, Kang, et al., ). It is also speculated that these washing processes could lead to the cross‐contamination of fresh products (Gombas et al., ; Murray et al., ).…”

Section: Introductionmentioning

confidence: 99%

Nonthermal Plasma–Liquid Interactions in Food Processing: A Review

Perinban

Orsat

Raghavan

2019

Nonthermal processing methods are often preferred over conventional food processing methods to ensure nutritional quality. Nonthermal plasma (NTP) is a new field of nonthermal processing technology and seeing increased interest for application in food preservation. In food applications of NTP, liquid interactions are the most prevalent. The NTP reactivity and product storability are altered during this interaction. The water activated by NTP (plasma‐activated water [PAW]) has gained considerable attention during recent years as a potential disinfectant in fruits and vegetable washing. However, detailed understanding of the interactions of NTP reactive species with food nutritional components in the presence of water and their stability in food is required to be explored to establish the potential of this emerging technology. Hence, the main objective of this review is to give a complete overview of existing NTP–liquid interactions. Further, their microbial inactivation mechanisms and the effects on food quality are discussed in detail. Most of the research findings have suggested the successful application of NTP and PAW for microbial inactivation and food preservation. Still, there are some research gaps identified and a complete analysis of the stability of plasma reactive species in food is still missing. By addressing these issues, along with the available research output in this field, it is possible that NTP can be successfully used as a food decontamination method in the near future.