Food sterilization technology from "hot processing" to "cold processing"

Food sterilization technology is one of the core technologies of the food industry, that is, the use of various means to kill food itself pollution, brought from food packaging containers, introduced by operators and equipment in the process of processing and preparation, and various harmful microorganisms in the production environment, so as to maintain food quality and reach a certain shelf life
.
Recently, Sun Yunjin, associate professor of the College of Food Science and Engineering, Beijing Agricultural University, made a breakthrough in the application of plasma sterilization technology in the field of agricultural production and food processing, and the first superion sanitize machine in Beijing universities was successfully trial-run
in Beijing Agricultural College.
Sun Yunjin said that low-temperature air plasma has the characteristics of killing microorganisms and decomposing organic matter, has a good killing effect on a variety of microorganisms in different foods, and has the characteristics of high efficiency, rapidity, no residue, low temperature and wide application range, which is of great application value
in the food industry.

The rise of non-thermal food processing technology

In recent years, in order to maximize the nutritional value of food, the food industry has continuously sought the research and development and application of new technologies, using a series of non-thermal processing technologies and equipment to conduct in-depth research on the transformation and innovation of food processing from traditional "hot processing" to "cold processing", and exploring low-temperature technology to ensure product quality and safety and achieve sustainable development
of the industry.

With the improvement of living standards and the development of the food processing industry, people pay attention to food safety at the same time, and the requirements for food nutrition are also increasing
.
Conventional heat sterilization technology will affect the nutritional and sensory quality of food, and may even produce toxic and harmful substances
such as acrylamide and furan.
Non-thermal sterilization technologies such as ultra-high pressure, irradiation, ultrasound, ultraviolet rays, ozone, and low-temperature plasma have avoided the limitations of thermal sterilization and have gradually received attention
.
However, non-thermal sterilization technologies such as ultraviolet, ultrasonic, and ozone usually need to be treated for 20-60 minutes to effectively reduce the number of microorganisms, which is time-consuming and labor-intensive, while ultra-high pressure sterilization can only use flexible packaging materials, limiting the packaging form
.

As a new type of non-thermal food processing technology, low-temperature plasma technology has great application potential
in the food field.
Low-temperature plasma is an active substance
such as high-energy electrons, excited particles, reactive oxygen species, and reactive nitrogen produced by gas discharge at atmospheric pressure and ambient temperature.
Low-temperature plasma technology has a good killing effect on a variety of microorganisms in different foods, and has the characteristics of
high efficiency, rapidity, no residue and low temperature.
As an emerging cold sterilization technology, low-temperature plasma has a killing effect on various pathogenic and decaying microorganisms existing in food, and the high-energy charged particles, active substances, ultraviolet light, etc.
produced will destroy cell membranes, proteins, nucleic acids, enzymes and other macromolecular substances in microorganisms, thereby inhibiting the growth and reproduction of microorganisms, and finally inactivating
them.
The high-energy particles and active substances it produces can not only kill the microorganisms present in food for food preservation, but also reduce pesticide residues, improve food processing characteristics, and remove peculiar odors
in food.

Effectively extend the shelf life of fruits and vegetables

In order to effectively improve the level of industrial application of plasma technology and solve the preservative preservation and quality safety issues of agricultural products and food, in October 2020, the Capital Institute of Agricultural Product Safety Industrial Technology of Beijing Agricultural University established the "Plasma Engineering Center" (Pasman Laboratory), and invested special incubation funds to set up a R&D team with Sun Yunjin as the core, which is responsible for the application research and development
of low-temperature plasma technology in the whole industry chain in the field of agricultural production and food processing 。 Based on low-temperature plasma, the R&D team adopts original air sanitize and penetration sanitize technology, and then builds a digital open and accurate management and control system through smart cloud services, realizing rapid integration
of various application scenarios.

Toon is a favorite vegetable known as "tree vegetable", but it is difficult to store and its taste changes
when frozen.
In order to break this bottleneck that restricts the development of the toon industry, Sun Yunjin's team has developed a plasma gas preservation technology that can improve the shelf life of toons, breaking the technical barriers of fresh toon preservation, extending the shelf life of toons, and helping to extend the industrial chain
.

The research team took the picked fresh toon as the research object, divided into two groups according to the size of the toon, and stored it at 4°C after 0 and 10 minutes of electric treatment, and observed and recorded
every 2-3 days.
The researchers said that the control group had some wilting and a stronger odor from the fifth day of storage; From the 7th and 9th days, the odor is weak and the degree of wilting is too great; 19 days begins to grow hair, smells of decay
.
The plasma treatment group did not change significantly at the beginning, with slight wilting at 19 days; On the 31st day, the smell is lighter and there is no rotten taste; After day 40, the samples were slightly hairy and wilted
.
In terms of appearance, there will be color changes in both the control group and the treatment group, that is, the initial purple-red color gradually fades to green, and the color change of the control group is more obvious
.
The results show that plasma gas preservation technology can extend the shelf life of toon by more than 3-5 times, and the preservation effect is outstanding
.

Improve logistics sanitize efficiency

As the epidemic prevention and control has entered the normalization, how to sanitize express parcels and whether they are safe and reliable has become a topic
of concern.
How to ensure the safety of express parcels and achieve all-round sanitize is a problem
faced by logistics companies.
A few days ago, the superion sanitize technology sanitize conveyor for viruses and bacteria on the surface of express parcels developed by Sun Yunjin's team was put into trial operation
at the Cainiao Station of Beijing Agricultural College.
The device is easy to operate and supports on-site operation, from sample processing to sterilization in just 30 seconds
.
The equipment uses air plasma cold sterilization technology, which can be used for disinfection of express parcels, personal belongings, edible food and other surfaces, and realizes effective sanitize
of more than 20 kinds of viruses and bacteria such as new coronavirus, E.
coli, avian influenza, norovirus, etc.

The courier is disinfecting the package with a superionic sanitize

The successful operation of the superion sanitize conveyor not only provides a further guarantee for campus epidemic prevention and control, but also means that the air plasma cold sterilization technology solution has been successfully transformed into a product solution, which has the foundation
to provide sanitize services for the logistics industry.
The relevant person in charge of a courier company said that compared with traditional disinfectant spraying and disinfection, using this equipment to disinfect the skin will not irritate, and the courier is invisibly equipped with a "safety lock"
.

Sun Yunjin said that from the current point of view, the products developed by using this technology can provide a full-process integrated sanitize solution for logistics, and I believe that in the future, plasma technology can provide one-stop solutions
for livestock and poultry epidemic prevention and safe production around the entire industry chain of the breeding industry.

(Zhao Chengming)

China Food News(November 02, 2022 Version 04)

(Editor: Gao Na).