Sterilization Technology Research Articles

Curcumin-Mediated Sono-Photodynamic Treatment Inactivates Listeria monocytogenes via ROS-Induced Physical Disruption and Oxidative Damage.

Sono-photodynamic sterilization technology (SPDT) has become a promising non-thermal food sterilization technique because of its high penetrating power and outstanding microbicidal effects. In this study, Listeria monocytogenes (LMO) was effectively inactivated using curcumin as the sono-photosensitizer activated by ultrasound and blue LED light. The SPDT treatment at optimized conditions yielded a 4-log reduction in LMO CFU. The reactive oxygen species (ROS) production in LMO upon SPDT treatment was subsequently investigated. The results demonstrated SPDT treatment-induced excessive ROS generation led to bacterial cell deformation and membrane rupture, as revealed by the scanning electron microscope (SEM) and cytoplasmic material leakage. Moreover, agarose gel electrophoresis and SDS-PAGE further revealed that SPDT also triggered bacterial genomic DNA cleavage and protein degradation in LMO, thus inducing bacterial apoptosis-like events, such as membrane depolarization.

Characterization of volatile compounds in evening primrose oil after γ‐irradiate

AbstractEvening primrose oil (EPO) is rich in linolenic acid, which has important physiological activity and attracted more and more attention. As a cold sterilization technology, irradiation is widely used in food preservation. However, the effect of irradiation on the flavour quality of EPO is unclear. The volatile aroma compounds examined by gas chromatography‐mass spectrometry (GC‐MS), combined with the odour activity value, are used to identify important odours in EPO. Principal component analysis (PCA), cluster heatmap analysis, and orthogonal partial least squares discriminant analysis are used to analyse the data to illustrate the impact of different radiation doses. The results show that the types and composition of volatile substances have changed, among which aldehydes have increased the most. Hexanal, (E,Z)‐2,4‐decadienal, and (E)‐2‐octenal, 1‐octen‐3‐ol were confirmed to play an important role in the formation of the green, fast, oily, and fishy aroma profile of EPO. In addition, the cluster analysis and PCA analysis showed that the flavour of 5 and 10 kGy was similar, but it was different from that of 1 kGy. In general, after the irradiation treatment, the flavour quality of EPO deteriorates, and the content of undesirable flavour substances increases. Additionally, the potential formation pathways and mechanism of volatile compounds were discussed. The research will help us to understand the change of the violate compounds under the γ‐irradiate process.

PiggyBac-based transgenic RNAi of serine protease 2 results in male sterility in Hyphantria cunea

Fall webworm, Hyphantria cunea, is a global invasive forest pest that causes serious damage to the economy and ecosystem of agriculture and forestry. Due to the extent of the problem and the difficulty of conventional chemical control, new technologies must be pursued, such as genetic-based inheritable insect sterile technology (gSIT), which exhibits promise for pest control. In the present study, we established a piggyBac-based transgenic system in fall webworm and generated a dominant male-sterile strain by targeting the seminal fluid protein serine protease 2 (Hcser2), displaying an outstanding trait of gSIT. First, an RNA polymerase type III (Pol III) promoter, the HcU62 small nuclear RNA (snRNA) gene promoter, was identified and characterized through direct injection of RNAi plasmids in vivo. Quantitative real-time PCR revealed that HcU62 had the greatest knockdown efficiency of the Hcyellow gene among five short hairpin RNA (shRNA) plasmids tested, designated HcU61–HcU65. Second, subsequent application of piggyBac-based transgenic RNAi (HcU62: shHcyellow, Ysh2) significantly reduced the expression level of the Hcyellow gene, resulting in a stable yellow observable phenotype from the larval to pupal stages in Ysh2 transgenic mutants. Finally, an HcU62-driven transgenic RNAi strain targeting the Hcser2 gene was obtained, resulting in a dominant male-sterile phenotype. Significantly, this process did not affect the growth, development, mating behavior or egg laying of the mutants, and the dominant sterile trait could be inherited in the next generation through female Hcser2 mutants. Furthermore, CRISPR/Cas9-mediated disruption of the Hcser2 gene further confirmed the dominant sterile phenotype, supporting it as a generalized target for genetic control of H. cunea. This study reports the first piggyBac-mediated transgenic system in H. cunea, providing a promising genetic method for controlling this pest by targeting Hcser2 gene.

Inactivation mechanism of catalytic infrared against Pseudomonas aeruginosa and its decontamination application on dry green Sichuan pepper (Zanthoxylum schinifolium)

Catalytic infrared (CIR) technology for sterilization has not been widely applied owing to the lack of comprehensive and in-depth mechanistic research. This study aims to explore further the inactivation mechanism of CIR against Pseudomonas aeruginosa in green Sichuan pepper (GSP). First, the working pattern of the CIR was investigated using a colony counting method in different layouts. The results indicated that the bacteriostatic effect on GSP was weaker than that on plates with low-dose CIR radiation, and both the surrounding air and surface moisture content affected the sterilization rate of P. aeruginosa. Second, the bacteriostatic mechanism of CIR against P. aeruginosa was investigated. The results indicated that the bacteriostatic effect of CIR could be mainly caused by the destruction of the cell membrane, inhibition of swimming motility, and membrane dysfunction simultaneously, and it was also caused by weaker DNA breakage compared with pulse strong light. Finally, the flavour influence of CIR in GSP was determined in terms of volatile oil content, aroma component, alkaloid content, and colour change. After 0–4 min of CIR treatment, the changes in the flavour of GSP were all within the acceptable range. Consequently, CIR technology is a promising approach for effective decontamination of the GSP surface, which works mainly on cell cover and can weakly penetrate the cell membrane.

Application of Pulsed Light Sterilization Technology in Food and Packaging Materials

Pulsed light is a new efficient environment-friendly non-thermal sterilization technology and it has a great development potential in food industry. This article reviews the sterilization mechanism of pulsed light and its applications in fruits and vegetables, meat products, dairy products and food packaging materials et al, the coupling effects of pulsed light and other preservation technologies, practical applications of pulsed light in food industry as well as the safety of using pulsed light. Pulsed light can not only widely destroy a variety of pathogenic bacteria, but also basically do not change the properties of foods and food packaging materials. It has huge application potential in improving food safety and extending food shelf life. The coupling of pulsed light and other fresh-keeping technology also has better effects in terms of sterilization effect, sensory quality, and nutrient content retention than single fresh-keeping technology. This review hopes to provide a theoretical reference for researchers to further understand the pulsed light sterilization technology and expand its application fields.

Deployment of Sterile Insect Technology (SIT) on a Large Scale Prevented an Outbreak of Dengue in a Brazilian City

Deployment of Sterile Insect Technology (SIT) on a Large Scale Prevented an Outbreak of Dengue in a Brazilian City

Standardization of sterilization regimes for textile materials under pandemic conditions (COVID-19) by the method of ionizing radiation

Methods for sterilizing textile materials in a pandemic (COVID-19) and the disadvantages of these methods are presented. A number of modern scientific works related to the sterilization of textile materials in a pandemic are considered, aimed at developing a technology for sterilizing protective medical masks and medical suits by radiation methods using gamma radiation. As a result of the analysis, it was found that the use of gamma radiation is a very dangerous technological process since natural sources are used - gamma rays, radiation technologies with gamma radiation are difficult when disposing of spent energy sources and are not easy to maintain. For sterilization of textile materials, the method of ionizing radiation is proposed. The essence of the method is that the textile material is sterilized by accelerated electrons. The expediency of carrying out theoretical and experimental research has been determined. It was found that the main criterion for sterilization of textile materials is the absorbed dose. The absorbed dose is determined experimentally, but such a procedure is time-consuming and resource-intensive, and it is not always possible to carry it out. Therefore, to calculate the absorbed dose, it is proposed to apply the mathematical formula of the absorbed dose of medical textile materials, depending on the frequency of passage of pulses of the accelerated electron beam, conveyor speed and geometric parameters of textile materials, the mathematical formula will allow finding the optimal technological modes of the sterilization process. Using the mathematical model of the absorbed dose of radiation by the material with the proposed technology, taking into account the properties of materials, it is possible to calculate the modes of irradiation of various textile materials that differ in size, shape, and physical properties, which will make it possible to develop a system of normative modes for the technology of radiation-physical sterilization and to ensure the legislative and regulatory requirements of hygiene in conditions of a pandemic.

Pengaruh Sterilisasi Ultraviolet-C Terhadap Perubahan Dimensi Hasil Cetak Alginat

Background: Impression material is a material that is used to negatively replicate a patient's tooth structure and periodontal, and it is preferable to sterilize the negative model first before the casting process to avoid cross-contamination between the dentist and the patient. Then casts are made from the impression using type III gypsum, producing diagnostic cast or working cast. Ultraviolet-C (UV-C) sterilization was introduced as the lastest sterilization technology from UV rays with an effectiveness rate of 99.9% in lysing germs, viruses, and fungi. The wavelength of UV-C light itself is also the smallest at 200-270 nm compared to UV-A 320-400nm and UV-B 270-320nm. Objective: To determine the effect of UV-C sterilization on the changes in dimension of alginate impressions. Methods: The type of this research was experimental laboratory research. The samples were taken from the maxillary model which were divided into 2 groups, namely (A) the treatment group where cast was irradiated with UV-C and (B) the control group where casts were sprayed with disinfectant. Samples of the treatment and control groups were both sterilized first before casted. For the treatment group, casts were put in a UV-C box for 10 minutes. For the control group, casts were sprayed with disinfectant, then covered with a moistened tissue and put into a plastic seal. Result: UV-C sterilization did not show significant changes toward dimensional changes of alginate impressions. Conclusion: UV-C sterilization can be used to sterilize alginate impression materials because it does not cause significant dimensional changes of the impression

Research Progress in the Control of Salmonella in Almond by Sterilization Technology

Almond is a very popular nut food, but at the stage of harvesting from the orchard, it may be infected with Salmonella from the soil, which is harmful to human health. After the 2001 and 2004 Salmonellosis outbreaks that were associated with raw almonds, ensuring the microbial safety of almonds by treating them to achieve a minimum 4 lg CFU/g reduction of Salmonella population became mandatory in California, the world’s largest almond producer. Therefore, the control of Salmonella in the production of almonds is particularly important. This paper briefly summarized the effect and research progress of two types of sterilization techniques (pyrobacterial, non-pyrobacterial) in controlling Salmonella in almonds, in order to provide reference for the application of sterilization technology in the control of Salmonella in almonds.

Effects of high pressure and thermal processing on quality properties and volatile compounds of pineapple fruit juice

Traditional pasteurization method usually has negative impacts on color, flavor, and bioactive compounds of fresh fruit juice. Therefore, it is critically important to develop novel non-thermal sterilization technologies to overcome these problems. In this study, high pressure processing (HPP) (500 MPa/10 min) and thermal processing (TP) (95 °C/3 min) treatments on pineapple fruit juice were comparatively evaluated by monitoring their influences on microbial counts, physicochemical parameters, bioactive components, antioxidant capacity, and volatile compounds during storage of 28 days at 4 °C. The microbial safety was ensured in both HPP-treated and TP-treated pineapple fruit juice, and further cold storage result showed at least a shelf life of 21 days at 4 °C. Both HPP and TP treatments have significant effects on the turbidity and sedimentation index of pineapple juice. During the shelf life, the sugars, pH, titratable acidity, total soluble solids, and sedimentation index of HPP-treated groups exhibited no significant change, while the color, bioactive components, antioxidant capacity, and relative content of volatile compounds in both TP- and HPP-treated groups were remarkably changed. Moreover, the pineapple fruit juice with HPP treatment showed a greater retention of original color, bioactive components, antioxidant activity, and volatile compounds in comparison with TP-treated group. In summary, HPP treatment could not only control the microbes in pineapple fruit juice, but also better retain the qualities of pineapple fruit juice, which provided an effective alternative to conventional thermal processing for production of high quality pineapple fruit juice. • HPP treatment had no significant influence on physicochemical properties of pineapple fruit juice. • HPP-treated pineapple fruit juice retained higher levels of bioactive ingredients and antioxidant capacity. • The aroma composition of HPP-treated pineapple fruit juice was closer to fresh pineapple fruit juice.

Cold plasma aseptic packaging

Cold plasma aseptic packaging

A Case Study on Commercialization of Appropriate Technology in Lao PDR: Focusing on Lao-Korea Science and Technology Center

The purpose of this paper is to examine commercialization model of appropriate technology through the case of the LaoKorea Science and Technology Center (LKSTC). LKSTC has developed washing, water treatment, and sterilization technology in the agrifood sector and three types of pico-hydro generator, Pico-solar hybrid system, and energy remote monitoring technology in the renewable energy sector. Commercialization of appropriate technology was successfully carried out through the establishment of Kaipan community business, school enterprises, and social enterprise. The policy implications are as follows. First, the commercialization of appropriate technology in developing countries should enhance the linkage with the regional development policies of the recipient countries. Second, in order to minimize market risk, innovative technology development and local startup networks should be properly established. Finally, the mid and long term efforts are needed to increase the sustainability of the business.

Research on Key Technology of Electrochemical Sterilization and Physical Application for Circulating Cooling Water

As a high-efficiency, low-cost, convenient and environmentally friendly sterilization technology, electrochemical disinfection has developed rapidly in recent years. Electrochemical sterilization is an environmentally friendly sterilization technology. The research progress of this technology in the recent 30 years in sterilization mechanism and electrode materials is summarized. The mechanism of electrochemical sterilization includes the chemical effects of active chlorine, active intermediates, copper or silver ions, and the physical effects of electric fields; the electrode materials used are titanium anode, carbon cathode, and anode. The article combined with electrochemical equipment in a thermal power plant cold open circulating cooling water treatment experiment. Experimental research found that under the conditions of current density of 120A/m2, residence time of 10s, and electrode spacing of 1.8cm, the bactericidal effect can reach 97%. Under certain experimental conditions and a certain period of time, the total number of heterogeneous bacteria in the circulating cooling water after treatment can be effectively inhibited.

Pengembangan Karakterisasi Gelembung Mikro Menggunakan Metode PIV beserta Pemantauan dengan IOT

The development of microbubble technology has been widely used in various fields. One of these areas is sterilization technology using microbubbles to speed up and increase the effectiveness of the sterilization process. One example is room sterilization using vaporized ozone gas microbubbles which can minimize the spread of the Covid-19 virus. However, research and development of microbubbles are still not much related to the characterization of their size and hydrodynamic properties. In this study, we propose the development of a continuous characterization of the size of microbubbles using the image analysis method. Image analysis aims to find the displacement vector using particle image velocimetry (PIV) techniques. The Hadamard-Rybczynski equation was used to calculate the size of the microbubbles based on the rising velocity vector of the microbubbles. The image capture process uses an LED light shadow technique to get a brighter and more stable image. The template matching algorithm is used to speed up the displacement vector analysis process used in the PIV technique. The analysis process is carried out in-situ in parallel processing using the python program on the raspberry pi4 unit. The analysis process uses three program services that run parallel, namely recording, pre-processing, and processing services. The measurement process uses three validations, namely pixel validation, template matching algorithm validation, and interrogation window. Bubble size data is displayed in the form of real-time graphs and size distribution histograms online using IoT. The test results show the size distribution of the microbubbles produced has an average of 14.60 µm with a deviation value of 0.11µm.

Silage fermentation characteristics and microbial diversity of alfalfa (Medicago sativa L.) in response to exogenous microbiota from temperate grasses.

The objective of this study was to explore the microbiological factors that cause the difference in silage fermentation characteristics between grass and legume. Specifically, the effects of epiphytic microbiota from alfalfa, oat and Italian ryegrass on ensiling characteristics and microbial community of alfalfa were assessed. By γ-ray irradiation sterilization and microbiota transplantation technology, the sterile alfalfa was inoculated as follows: (i) aseptic water (STAL); (ii) epiphytic bacteria from alfalfa (ALAL); (iii) epiphytic bacteria from oat (ALOT); (iv) epiphytic bacteria from Italian ryegrass (ALIR). Alfalfa at the initial flowering stage was ensiled in laboratory-scale silos for 1, 3, 7, 14, 30 and 60 days. Compared with ALAL and ALIR, higher lactic acid contents and ratio of lactic acid to acetic acid, and lower acetic acid, propionic acid, ethanol and ammonia nitrogen contents were observed in ALOT after 60 days of fermentation. In each treated group, Lactobacillus was the most dominant genus after 60 days of ensiling. Relatively higher abundance of Weissella, Hafnia-Obesumbacterium, Enterobacteriaceae or hetero-fermentative Lactobacillus was found in ALAL and ALIR after 60 days. Co-occurrence network analysis proved Pediococcus and Lactococcus were pivotal in deciding the fermentation pattern of alfalfa silage. According to the 16S rRNA gene-predicted functional profiles, the metabolism of amino acids was inhibited by the epiphytic microbiota from oat. Overall, ALOT showed a homo-fermentative process, whereas ALAL and ALIR exhibited a hetero-fermentative pattern. Furthermore, the exogenous microorganisms inhibiting the metabolism of amino acids can be a good potential source to improve the silage quality of legume forage.

Roles and Principles of Sterilisation Process in Palm Oil Mills

Sterilisation in palm oil mills is considered a pre-treatment process as it affects stripping efficiency and oil quality. Although sterilisation technology has been well-established in the palm oil milling industry, the roles and principles of sterilisation, particularly related to the chemical changes in fruits and stalks occurring during the process, have been rarely reported. The review begins with the background literature on the biochemical properties of the FFBs, such as the compositions of binding carbohydrates and the phenomena of natural fruit detachment. Followed by the harvesting practice to understand the type of FFBs supplied to the industry. In addition, a comparison of the well-established conventional and alternative sterilisation technologies and sterilisation functions is critically reviewed and assessed. Establishing the current sterilisation process initiatives to address the natural fruit’s separation more efficiently in palm oil mills is important. Particularly visualise sterilisation as a breakup of specific binding carbohydrates that leads to strippability. It will provide a further understanding of the sterilisation mechanism, which would benefit the palm oil miller in optimising the processing of fresh fruit bunches. The information provided in this review is necessary to mitigate the percentage of unstripped bunches and reduce the oil losses and ultimately enhance the oil extraction rate.

X‐ray sterilization of biopharmaceutical manufacturing equipment—Extractables profile of a film material and copolyester Tritan™ compared to gamma irradiation

The biopharmaceutical industry gains enormous flexibility in production processes by using sterilized preassembled single‐use devices. Gamma irradiation is an established sterilization technology that may be restricted in the future by the availability of 60Co as irradiation source and irradiation capacities. X‐ray technology is considered an alternative type of radiation for sterilizing SU equipment. In the context of extractables and leachables—one concern connected with the use of single‐use process equipment—the effect of X‐ray irradiation on the extractables profile of the materials needs to be compared to established gamma irradiation to qualify this alternative technology. An approach is presented to obtain robust and comprehensive extractables data for materials used in SU devices after sterilization either using X‐ray or gamma irradiation. A careful selection of the test items and the test design allows a one‐to‐one comparison of data obtained from a combination of orthogonal analytical techniques. The extractables of a modern SU film material and the copolyester Tritan™ are evaluated. The data presented allow a risk evaluation on the safety of this new sterilization modality for biopharmaceutical applications. It is demonstrated that the extractables profile of a polymer is not affected by the type of irradiation used for sterilization.

Water purification system based on self-powered ozone production

Ozone treatment is an excellent sterilization technology, but high voltage is essential for ozone generation. Here, for the first time, we report a multifunctional water purification system based on self-powered ozone generation. The TENG with “like charges repel” strategy (LCR-TENG), which can obtain a maximum short-circuit current of 22.15 uA, a peak power of 80 mW, and a maximum transient voltage over 30.7 kV, is designed as the power source of the system. Then, an air-breakdown-discharge is generated by this TENG to support the ozone generation, while the maximum concentration of generated ozone can be up to 30 mg/m3 and it is enough for the application of water treatment. With continuous injection of ozone into solutions, Rhodamine B with 5 ppm concentration can be degraded by 97.6% in 20 min. The ozone generated by the system are effective for bio-sterilization in water, indicating the promising application for the treatment of organic matter and microorganisms in water. A variety of external loads, such as ultraviolet lamp and step-down circuit can be simultaneously integrated in the current loop and the function of the system can be further expanded without disturbing the ozone generation. Hence, this work broadens the high voltage applications of TENG for the multifunctional purification system.

A Smart Sterilization Robot System With Chlorine Dioxide for Spray Disinfection

The highly infectious and serious nature of coronavirus disease 2019 (COVID-19) has highlighted the need for hospital space disinfection technology and the prevention of human exposure to pathogenic environments. This research developed novel chlorine dioxide (ClO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) sterilization technology to reduce bacteria and viruses in the air and on surfaces. A smart sterilization robot system was also developed to spray disinfectants in operating theaters or patients’ rooms, designed according to the results of controlled experiments and the requirements for hospital disinfection. The system was built incorporated a semi-automatic remote-controlled module and an automatic intelligent disinfection function; that is, it could operate independently according to specific epidemic prevention strategies, which were implemented using a combination of Internet of Things (IoT) applications and a gesture recognition function. The elimination of Escherichia coli ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E. coli</i> ) bacteria on sample plates was 99.8 % effective. This paper reviews the evolution of various disinfection technologies and describes a disinfection robot system in detail.

Effect of epiphytic microbiota from napiergrass andSudan grass on fermentation characteristics and bacterial community in oat silage.

To investigate the effects of epiphytic microbiota from napiergrass and Sudan grass on ensiling characteristics and microbial community of oat silage. By γ-ray irradiation sterilization and microbiota transplantation technology, the sterilized oat was inoculated as follows: (a) aseptic water (STOT), (b) epiphytic bacteria on oat (OTOT), (c) epiphytic bacteria on napiergrass (OTNP) and (d) epiphytic bacteria on Sudan grass (OTSD). STOT remained in the unfermented state based on similar chemical components with fresh oat. Compared with OTOT and OTSD, higher lactic acid content and ratio of lactic acid to acetic acid, and lower pH, acetic acid and ammonia nitrogen contents were observed in OTNP after 60days of ensiling. At the late stage, Lactobacillus was the most predominant in each group. Lactococcus was eventually replaced by Lactobacillus in OTSD, whereas Lactococcus was found throughout the whole ensiling process in OTNP. Higher abundance of Weissella was observed in OTSD at the early and late stages. The result of co-occurrence network analysis proved that Lactococcus was pivotal in determining the silage fermentation pattern during ensiling. According to the 16S rRNA gene-predicted functional profiles, the inoculation of epiphytic microbiota from oat enhanced the metabolism of amino acids, whereas the inoculation of epiphytic microbiota from napiergrass and Sudan grass accelerated the carbohydrate metabolism. The epiphytic microbiota on napiergrass promoted a homo-fermentative process, whereas the epiphytic microbiota on oat and Sudan grass facilitated a hetero-fermentative pattern in oat silage, which was closely related to the abundance and metabolism of Lactococcus, Weissella and Lactobacillus. The exogenous microorganisms that promote the carbohydrate metabolism and inhibit the metabolism of amino acids could be a good potential source to improve the silage quality of temperate grass.