Investigation of microwave sterilization characteristics of sous vide processed pork patties depending on composition

The conventional steam-based sterilization of crude palm oil (CPO) in Indonesia is known to be energy- and water-intensive, as well as time-consuming. This necessitates more efficient and sustainable alternatives, such as microwave oven heating. While microwave applications in CPO sterilization have been explored as a more efficient and sustainable alternative, existing studies often lack comprehensive optimization and a systematic investigation of key process parameters. This study aimed to optimize fresh fruit bunch (FFB) sterilization using a microwave oven to identify optimal operating parameters for maximizing oil extraction yield and minimizing Free Fatty Acid (FFA) content. The Central Composite Design (CCD) within Response Surface Methodology (RSM) was employed as a statistical technique to model the process and ensure the validity of the results. Three independent variables were investigated: sterilization time (6–20 min), fruit mass (396–1104 g), and fruit maturity level (ripe and over-ripe), resulting in twenty-six experimental combinations. Optimal conditions for maximum yield and lowest FFA were determined at 6 min sterilization time and 550 g fruit mass for both maturity levels. Conversely, suboptimal conditions at 11.5 min and 150 g fruit mass for both maturity levels resulted in the lowest yield and highest FFA. This research provides crucial insights for developing an optimized microwave sterilization technique, enhancing palm oil processing efficiency and product quality. The findings underscore the potential for a scalable, low-energy sterilization method that could significantly reduce the environmental footprint of CPO production, instilling optimism about the positive impact of this research.

Peanut skin is a low-value by-product in the peanut oil and peanut product industry, with only a small amount utilized as animal feed while the majority discarded as waste. However, peanut skin contains high-value proanthocyanidins (PCs). Therefore, the objective of this paper is to optimize the extraction conditions for PCs, thereby increasing the added value of peanut skins. The results demonstrated that under the optimal conditions—liquid–solid ratio 1 (50:1 mL/g), temperature 1 (50 °C), ethanol concentration 2 (65%), and time 2 (16 min) — the yield of lyophilized crude PCs extract reached 129.14 ± 2.45 mg/g, with a PCs purity of 50.61 ± 2.27%. The crude PCs extract exhibits significant antioxidant activities. Under conditions including temperatures below 65 °C, pH values less than 7, and the presence of Na+, K+, Ca2+, Cu2+, Mg2+, Zn2+, glucose, sucrose, ascorbic acid, sodium bisulfite, as well as microwave sterilization, boiling water sterilization, pasteurization, and UV sterilization, crude PCs extract demonstrates favorable antioxidant stability. The process optimization and antioxidant activity investigation of crude PCs extract provide novel insights for the comprehensive processing and utilization of peanut skins.

Effect of sterilization methods on quality and storage characteristics of tofu fermented by lactic acid bacteria

The present study evaluated the effect of chemical disinfectants and microwave sterilization on the removal of biofilm containing Pseudomonas aeruginosa, Streptococcus mutans, and Candida albicans from type IV dental stone. One hundred twenty-eight (N = 128) type IV dental cast stone specimens were prepared, and biofilms of microorganisms were cultured. Dental stone samples were subjected to disinfection protocols, including 0.5% chlorhexidine (CHX), 0.5% sodium hypochlorite (NaOCl), 20% neem extract, and microwave irradiation for 1 to 5 minutes. Colony forming unit (CFU) counts and scanning electron microscopy were utilized to witness changes in the biofilm, pre- and postdisinfection/sterilization. For P. aeruginosa, significant (p < 0.05) decrease in CFU counts after 1 minute (from 233 to -215) and 2, 3, and 5 minutes (from 233 to -233) were observed after CHX treatment. After microwave radiation, a significant decrease in CFU counts was also observed after 1 minute (from 233 to -130.3), 2 minutes (from 233 to -229), and 3 and 5 minutes (from 233 to -233). For S. mutans, a significant (p < 0.05) decrease in CFU counts was observed after 1, 2, 3, and 5 minutes (from 212 to -268) after NaOCl treatment and microwave radiation (from 212 to -271 after 1 minute and from 212 to -274.3 after 2, 3, and 5 minutes). For C. albicans, significant (p < 0.05) decrease in the CFU counts (1-5 minutes) was observed after CHX exposure, while NaOCl and microwave radiation demonstrated equal disinfection potency. Neem extract was effective to disinfect the dental stone; however, it was not as potent as the other disinfectants and microwave radiation. It was observed that exposure to CHX, NaOCl, and microwave radiation significantly reduced the microbial CFU counts. Although the use of neem extract also significantly reduced these CFU counts, this reduction was not as much as the other three tested materials. Further research exploring other chemical disinfectants with various concentrations is recommended.

Dual purpose of superheated steam treatment: Inactivating surface pathogens of pork belly and replacing blanching

A study of the effect of testing for diversification of healthcare waste sterilization and crushing facilities

The qualities of precooked foods can be significantly changed by the microorganisms produced during room temperature storage. This work assessed the effects of different antibacterial treatments (CK, without any treatment; microwave treatment, MS; microwave treatment and biological preservatives, MSBP) on the physicochemical properties and microbial communities of precooked crayfish tails during room temperature storage. Only the combination of microwave sterilization and biological preservatives significantly inhibited spoilage, as evidenced by the total viable count (4.15 log CFU/g) after 3 days of room temperature storage, which satisfied the transit time of most logistics companies in China. Changes in pH and TVB-N were also significantly inhibited in the MSBP group compared with those in the CK and MS groups. More than 30 new volatile compounds were produced in the CK groups during room temperature storage. However, in the MSBP groups, the volatile compounds were almost unchanged. The correlations between the microbial composition and volatile compounds suggested that specific bacterial species with metabolic activities related to amino acid, energy, cofactor, and vitamin metabolism, as well as xenobiotics biodegradation and metabolism, were responsible for the changes in volatile compounds. These bacteria included Psychrobacter, Arthrobacter, Facklamia, Leucobacter, Corynebacterium, Erysipelothrix, Devosia, Dietzia, and Acidovorax. Overall, our findings provide a foundation for the development of strategies to inhibit spoilage in precooked crayfish tails stored at room temperature.

Effectiveness of Microwave Sterilization on Surface Roughness of Polyvinyl Siloxane Impression Material

Effectiveness of Microwave Sterilization on Surface Roughness of Polyvinyl Siloxane Impression Material

A LINAC is an electron accelerating structure that uses radio frequency power to accelerate electrons. It has many scientific applications, and industrial applications such as microwave sterilization, pasteurization, and preservation of foods, and also in medical applications such as radiotherapy and medical sterilization. For thermally stable operation of the LINAC, it is required to prevent it from temperature-induced frequency shifts. LINAC operation at a high duty cycle dissipates average power of several kW in the structure. The main objective is to minimize the temperature rise to maximize the energy gained by the electron, reduction in thermal deformation of the cavities due to temperature rise and also to operate the LINAC within the efficient bandwidth of the RF source. An optimal thermal design with a web cooling channel system is developed for the efficient functioning of LINAC by using FEA. A water-cooled system (web cooling) for the room temperature 5 MeV traveling wave LINAC has been developed. It has been observed that the rise in temperature, thermal deformation, and energy loss are less in the developed design as compared to the pre-existing one. With the lower rise in temperature, the thermal detuning observed in LINAC will also be less. This makes the LINAC more efficient.

Microwave sterilization is a novel potential sterilization technology to improve food quality. An industrial microwave sterilization system was used to sterilize imitation crab meat under thermal processing intensity F0 = 1, 2, 3. The characteristics of the microwave process, such as heating rate, processing time, and C100, were calculated. In addition, the quality of processed imitation crab meat was investigated. Compared with the conventional retort method, microwave sterilization significantly shortened the processing time of imitation crab meat by 63.71% to 72.45%. Under the same thermal processing intensity, microwave sterilization has demonstrated better results than retort sterilization in terms of water-holding capacity, color, and texture. Furthermore, microwave-treated imitation crab meat ingredients had a greater capacity to bind water molecules and obtained a more appropriate secondary protein structure. In addition, microwave technology can better preserve the unsaturated fatty acids (UFA) of imitation crab meat, which are 9.14%, 1.19%, and 0.32% higher than the traditional method at F0 = 1, 2, 3. The results would provide useful data for the subsequent research and development of ready-to-eat surimi products.

Environmental and economic assessments of industry-level medical waste disposal technologies – A case study of ten Chinese megacities

Abstract Bacteria reduction and quality change of 3D printed carrots with different infill percentages (%) were studied after being treated with microwave (MW) at three power levels (120, 230, and 390 W). The color, appearance, texture (hardness, chewiness, and gumminess), and total polyphenol contents (TPCs) were comprehensively evaluated. The results showed that infill levels had no effect on bacterial population reduction but significantly affected the appearance of the samples after MW treatment. The total number of colonies (TNCs) were decreased by 0.27–0.68 (120 W, 60 s), 2.24–2.48 (230 W, 60 s), and 4.27–4.54 (390 W, 60 s) log CFU/g under the three MW treatments, respectively. 390 W MW treated achieved a very significant effect on inoculated Escherichia coli, with a death rate of 81.13%. MW treatment enhanced the hardness, chewiness, and TPC of the printed carrots as well as improved sticky mouthfeel without adversely affecting the visual color. The bacterial reduction effect of MW 390 W treatment for 60 s was relatively better. 60% infill sample was the best for the purpose of avoiding surface shrinkage and deformation of low infill samples and surface puffing of high infill samples.Practical applicationsIn this study, fresh vegetables were used for printing and MW sterilization was combined into 3D printing, so as to ensure the microbial safety of 3D printed products and provide technical basis for the sterilization treatment of meat, seafood, and other printed foods susceptible to microbial contamination.

Conventional palm oil milling undergoes multiple processes including sterilisation and stripping process that introduce a significant amount of water, resulting in a large amount of wastewater. Sterilisation is the first step in milling, where it is the pre-treatment to deactivate enzymes that increase free fatty acid before oil extraction. Microwave heating softens the surface of the palm fruit mesocarp, making it much easier to extract by solvent extraction. To fill the gap of the previous study, which is to apply two processes of drying and extraction, Soxhlet extraction and microwave will be proposed as an alternative to extracting a higher yield of palm oil mesocarp, replacing the conventional method, which uses the screw pressing process. The power of microwave pretreatment was found to be the most significant factor contributing to poor oil quality. Hence, iodination titration will be used to study the peroxide value (PV) in the oil palm that was extracted. During the sterilisation process, the exposure time and weight of the fruit were constant at 6 minutes and 200 g, respectively. At 800 W of microwave power, without the presence of water, it demonstrated a higher yield, which is around 59.31 %. Peroxide values from sterilized oil palm mesocarp are less than 10 meq/kg; thus, using a microwave sterilisation process followed by the Soxhlet extraction method is an alternative technique to produce crude palm oil.

Aseptic microwave sterilization and validation of food containing particles

The Energy Efficiency of Microwave Sterilization of Medical Waste According to the Characteristics of the Heating Element

Evaluation of pre-treated healthcare wastes during COVID-19 pandemic reveals pathogenic microbiota, antibiotics residues, and antibiotic resistance genes against beta-lactams

Abstract Continuous flow microwave sterilization for liquid food has advantages of a short time and high retention rate of nutrients. However, uneven microwave heating is the critical factor restricting the industrialization of microwave sterilization. This paper reviews the up-to-date research on the continuous flow microwave heating and the continuous flow microwave sterilization system for liquid food. The causes of the non-uniformity of continuous flow microwave heating are thoroughly discussed and the methods of improving the uniformity are proposed. Finally, the recommendations for future research of continuous flow microwave sterilization for liquid food are presented.

Low power microwave can effectively deactivate influenza type A virus through the nonthermal structure-resonant energy transfer effect, at a frequency matching the confined-acoustic dipolar mode frequency of the virus. Currently, aerosol is considered the major route for SARS-CoV-2 transmission. For the potential microwave-based sterilization, the microwave-resonant frequency of SARS-CoV-2 must be unraveled. Here we report a microwave absorption spectroscopy study of the SARS-CoV-2 and HCoV-229E viruses through devising a coplanar-waveguide-based sensor. Noticeable microwave absorption can be observed, while we identified the resonant frequencies of the 1st and 2nd dipolar modes of SARS-CoV-2 virus as 4 and 7.5 GHz respectively. We further found that the resonant frequencies are invariant to the virus titer, and we also studied the microwave absorption of HCoV-229E in weak acidity medium to simulate the common pH value in fluid secretion. Our results suggest the possible radiation frequency for the recently proposed microwave sterilization devices to inactivate SARS-CoV-2 virus through a nonthermal mechanism so as to control the disease transmission in the post-pandemic era.