Researchers in China report that air plasma can be used to kill biofilms found on the surfaces of perishable fruits and foods — significantly extending their shelf life, and reducing the world’s ‘food waste’ problem as well
Seeing fruit “turn bad and going to waste” inspired a team of researchers in China to explore using atmospheric pressure nonequilibrium plasma — already widely used for medical purposes — as a novel solution to extend the shelf life of fruit and other perishable foods.
When bacteria attaches to food surfaces, it can extract nutrients and continue to proliferate in the form of “biofilms.” Bacterial biofilms on food and food-processing surfaces diminish the food’s quality and safety.
But plasma sources are capable of killing bacteria such as Salmonella and E.coli on apples, as well as other types of spoilage microorganisms on mangos and melons, and Listeria on meat.
Now, researchers from China’s Shanghai Jiao Tong University and Huazhong University of Science and Technology report this week in the journal Physics of Plasmas, from AIP Publishing, about their computational study of how air plasma interacts with bacterial biofilms on an apple’s surface suggests that plasma technology could be used to decontaminate food in the future.
The fundamental concept behind the team’s work is to harness the reactive species generated by plasma to kill bacterial biofilms, which are notoriously difficult to wipe out.
“A biofilm consists of groups of microorganisms in which cells stick to each other, and these cells often adhere to a surface,” explained Xinpei Lu, a professor in the College of Electrical and Electronic Engineering at Huazhong University of Science and Technology. “These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance, which forms in different shapes and acts to protect the bacteria.”
For this work, the team simulated how the structure of the biofilm affects the discharge dynamics and then zeroed in on how the reactive species generated by the plasma are distributed on the biofilm’s surface — because it can later kill the bacteria within the biofilm.
“Plasma is formed when enough energy is added to a gas to ‘free up’ electrons from a significant number of atoms or molecules,” Lu said. “This process, known as ‘ionization,’ creates a mixture of positively charged particles, negatively charged particles, and various uncharged particles.”
High concentrations of so-called free radicals — very chemically reactive atomic or molecular fragments — often exist among these particles.
“These free radicals can quickly overwhelm the natural defenses of living organisms, which leads to their destruction,” he added.
Because plasma can easily produce more than a trillion free radicals per cubic centimeter of volume, it can serve as an efficient decontamination agent.
“Free radicals are one type of germ-killing agent generated via plasmas,” Lu pointed out. “Plasmas also produce other agents such as ultraviolet light, which sterilizes by causing DNA damage.”
Scientists previously observed that bacterial cell membranes sometimes rupture when exposed to plasma. This may be caused by charged particles attaching to the outer surface of the cell — inducing an electrostatic force that can overcome the tensile strength of the cell’s membrane by rupturing it.
So the team decided to explore how plasma interacts with biofilms and how the reactive species generated by the plasma are able to penetrate the cavity of the biofilm.
“Technically, we wanted to simulate the discharge (in millimeter gap distance) while capturing the effect of the biofilm’s mushroom shape (within a micrometer range) — an extremely challenging task,” said Lu.
What did they find?
“We discovered that the structure of the biofilm results in non-uniform distribution of reactive species during the plasma-on period,” he explained. “The mean free path of charged species at micron-scale permitted the plasma to penetrate into the cavity of the biofilm. This means that although the density of reactive species decreased by 6 to 7 orders of magnitude, the diffusion caused a uniform distribution of reactive species inside the cavity during its pulse-off period.”
In terms of applications, the team’s work indicates that air plasma can be used to kill bacteria within biofilms, which could “significantly prolong the amount of time fruit remains edible,” said Lu. Such a technique could be on the market within a few years, “once a low-cost plasma source is developed.”
The next step toward using low-temperature plasma technology for the decontamination of fruit is “to generate a uniform plasma over the irregular surface of the fruit, or to use a plasma jet to scan the surface of the fruit,” Lu noted. “We’re currently working on the latter method to achieve this goal.”
The Latest on: Air plasma
via Google News
The Latest on: Air plasma
- Plasma Waters’ Patented Technology Wins 1st Place in U.S. Army International Technology Contest and is Awarded Government Contracton September 17, 2022 at 2:23 am
The xTechInternational Competition’s goal is to evaluate, accelerate and deliver breakthrough technologies from global startups to the U.S. Army. These days it’s rare that fresh, abundant, clean water ...
- Air Plasma Cutter Market Research Report Analysis by Competition, Sales, Revenue, Market Size 2022 to 2028on September 16, 2022 at 12:31 pm
Pre and Post Covid is covered and Report Customization is available. The current "Air Plasma Cutter market" and ...
- Novel Plasma Disinfection Improves Buildings’ Air Qualityon September 16, 2022 at 5:54 am
The climate impact of large buildings and facilities, especially data centers and microchip plants, has been under scrutiny and has made recent headlines after New York Attorney General ...
- Anti-correlated plasma and THz pulse generation during two-color laser filamentation in airon September 9, 2022 at 10:06 am
The strong terahertz (THz) waves generated by femtosecond laser pulse induced gas plasma have drawn extensive attention owing to the ultra-wide spectral bandwidth, the high electric field strength, ...
- Plasma Viral Antigen Linked to Baseline Severity of COVID-19on September 7, 2022 at 7:39 am
Increased plasma viral antigen is associated with baseline severity of COVID-19 illness and with patient outcomes, according to a study published online Aug.
- Plasma Air Disinfection Machine Market Future Growth Opportunities 2022-2028on September 1, 2022 at 8:52 pm
The Plasma Air Disinfection Machine's evaluation of growth trends includes year-over-year growth in key geographies as well as gradual prospects in a number of key countries. Regionally ...
- Chinese scientists create a ‘plasma shower’ to improve stealth bomber performanceon August 26, 2022 at 3:44 am
A plasma device that could significantly improve the aerodynamic performance of a stealth bomber has been developed, according to a research team in northeastern China. The device is a strip of ...
- Chinese scientists create a ‘plasma shower’ to improve stealth bomber performanceon August 26, 2022 at 3:30 am
The plasma shower can stimulate air flow and increase the lift coefficient of an aircraft by nearly a third. This could prevent a stall, even if the aircraft drops to an unusually slow speed ...
- Plasma Air Disinfection Machine Market Located Worldwide Trends And Applicationon August 25, 2022 at 2:13 pm
MarketInsightsReports has recently launched a latest report on Plasma Air Disinfection Machine Market 2022 for its clients. This report offers the clients with factual data validated by industry ...
- Plasma Air Disinfection Machine Market Located Worldwide Trends and Applicationon August 24, 2022 at 5:00 pm
Aug 25, 2022 (Market Insight Reports) -- MarketInsightsReports has recently launched a latest report on Plasma Air Disinfection Machine Market2022 for its clients. This report offers the clients ...
via Bing News