Search results

In 2020, an outbreak of Salmonella Stanley linked to imported dried wood ear mushrooms affected 55 individuals in the United States of America. These mushrooms, commonly used in Asian cuisine, require processing, like rehydration and cutting, before serving. The US Centres for Disease Control and Prevention advise food preparers to use boiling water for rehydration to inactivate vegetative bacterial pathogens. Little is known about how food handlers prepare this ethnic ingredient and which handling procedures could enable Salmonella proliferation.

This study used content analysis to investigate handling practices for dried wood ear mushrooms as demonstrated in YouTube recipe videos and to identify food safety implications during handling of the product. A total of 125 Chinese- and English-language YouTube videos were analysed.

Major steps in handling procedures were identified, including rehydration, cutting/tearing and blanching. Around 62% of the videos failed to specify the water temperature for rehydration. Only three videos specified a water temperature of 100 °C for rehydrating the mushrooms, and 36% of the videos did not specify the soaking duration. Only one video showed handwashing, cleaning and sanitising of surfaces when handling the dried wood ear mushrooms.

This study found that most YouTube videos provided vague and inconsistent descriptions of the rehydration procedure, including water temperature and soaking duration. Food preparers were advised to use boiling water for rehydration to inactivate vegetative bacterial pathogens. However, boiling water alone is insufficient to inactivate all bacterial spores. Extended periods of soaking and storage could be of concern for spore germination and bacterial growth. More validation studies need to be conducted to provide guidance on how to safely handle the mushrooms.

This study will make a distinctive contribution to the field of food safety by being the first to investigate the handling procedure of a unique ethnic food ingredient, dried wood ear mushrooms, which has been linked to a previous outbreak and multiple recalls in the United States of America. The valuable data collected from this study can help target food handling education as well as influence future microbial validation study design and risk assessment.

Numerous food recalls and outbreaks were associated with wheat flour in recent years. Few consumers are cognizant of food safety risks associated with raw flour. The purpose of this study is to evaluate the food safety information and flour-handling behaviors presented in popular food blog recipes and in YouTube videos using cookie, cookie dough and egg noodle recipes as examples.

Eighty-five blog recipes and 146 videos were evaluated. Blog author and video host food-handling experience was classified as professional or nonprofessional. Food safety information and food-handling behaviors were evaluated for adherence to government and scientific recommendations.

Blog authors and video hosts demonstrated higher awareness of food safety risks associated with raw eggs compared to raw flour, which only translated into better adherence with recommended food-handling behaviors during ingredient addition steps. Cross-contamination from adding raw flour to the product was observed in 25% of videos, whereas cross-contamination from hosts adding raw shell eggs was observed 3% of videos. Blog authors and video hosts did not recommend or demonstrate handwashing after handling raw shell eggs nor raw flour, and fewer than 5% provided recommendations for cleaning work surfaces. Heat treatment methods to convert raw flour into ready-to-eat products were mentioned by 24% of blog authors and 18% of video hosts; however, the recommendations were not scientifically validated.

This study demonstrates the need to develop educational interventions that increase blog authors' and video hosts' awareness of risks associated with raw flour and that translate this knowledge into practiced behaviors.

The positive deviance (PD) focus group is a novel educational intervention that allows participants to discuss their food handling behaviors and decide to try recommended practices modeled by people like themselves. Currently, most food safety education is delivered through reading materials. The purpose of this paper is to explore the effectiveness of food safety education utilizing three interventions: PD, personal story reading and reading standard material.

A total of 89 pregnant women and 93 people with diabetes received food safety information through one of three intervention methods: PD, reading standard educational material (Standard) and reading material presented in a story format (Story). A survey assessed self-reported risk and food safety knowledge and personal hygiene before and after the interventions. Take-home assignments allowed participants to practice recommendations. Post class interviews and survey assessed knowledge gained and reported behavior change.

Compared to those who merely read educational information, participants in a PD Intervention had higher knowledge scores and adopted more safe handling recommendations. Involvement of the participants and the length of information exposure likely contributed to the significant difference between the interventions. This suggests that food safety education is most effective when delivered in a supportive discussion format. Health education programs for these vulnerable groups should endeavor to deliver safe food handling guidelines through a PD approach.

Previous research demonstrated the effectiveness of PD when delivering nutrition education. This is the first paper that explored the effectiveness of a PD intervention in delivering safe handling recommendations.

This study aims to achieve the post-stall pitching maneuver (PSPM) and decrease the deflection frequency of aircraft actuators controlled by the robust backstepping method based on event-triggered mechanism (ETM), nonlinear disturbance observer (NDO) and dynamic surface control (DSC) techniques.

To estimate unsteady aerodynamic disturbances (UADs) to suppress their adverse effects, the NDO is designed. To avoid taking the derivative of the virtual control law directly and eliminate the coupling term of the system states and dynamic surface errors in the stability analysis, an improved DSC is developed. Combined with the NDO and DSC techniques, a robust backstepping method is proposed to achieve the PSPM. Furthermore, to decrease the deflection frequency of the aircraft actuators, a state-dependent ETM is introduced.

An ETM-and-NDO-based backstepping method with an improved DSC technique is developed to achieve the PSPM and decrease the deflection frequency of aircraft actuators. And simulation results are presented to verify the effectiveness of the proposed paper.

Few studies have been conducted on the control of the PSPM in which the lateral and longitudinal attitude dynamics are coupled with each other considering the UADs. Moreover, the mechanism that can decrease the deflection frequency of aircraft actuators is rarely developed in existing research. This study proposes an ETM-and-NDO-based backstepping scheme to address these problems with satisfactory performance of the PSPM.

In this paper, boric acid was loaded on the surface of expandable graphite (EG), polyvinyl alcohol (PVA) and silane coupling agent (KH550) served as a bridge. The purpose of this study was to improve the flame retardant properties of semi-rigid polyurethane, meanwhile, the mechanical properties of the foam got ameliorated.

PVA was dissolved in hot water. EG was added to this solution. After stirring for 0.5 h at 85°C in ultrasonic agitation, the system was put at room temperature to cool. The silane coupling agent KH550 was added dropwise into the solution system, stirring to fully hydrolyze. Boric acid was added into the system, placing it in an oven at 90°C to dry after filtration. Changing of flame retardant properties and mechanical properties of semi-rigid polyurethane adding modified EG were characterized.

The flame retardant performance of the foam with EG has been improved, whereas the tensile strength decreased with an increase in the content of EG. After adding modified EG, compared to semi-rigid polyurethane with EG, flame retardant performance and tensile strength of the foam improved.

In the study reported here, the surface of EG was modified by boric acid. The modified EG was added into semi-rigid polyurethane foam. The flame retardant performance and tensile strength of the foam after adding modified EG were discussed. Results of this research could benefit in-depth study of the influence of adding modified EG to semi-rigid polyurethane. The study could promote the application of flame-retardant polyurethane foam.

The flame retardant performance and tensile strength of the semi-rigid polyurethane were improved by adding modified EG. The effects of modified EG on the flame retardant performance and tensile strength of semi-rigid polyurethane were discussed in detail.

The purpose of this paper is to prepare a spherical modifier-modified activated carbon fiber of high specific capacitance intended for electrode materials of supercapacitor.

In this study, phenolic-based microspheres are taken as modifiers to prepare PAN-based fiber composites by electrospinning, pre-oxidation and carbonization. Pearl-chain structures appear in RFC/ACF composites, and pure polyacrylonitrile fibers show a dense network. The shape and cross-linking degree are large. After the addition of the phenolic-based microspheres, the composite material exhibits a layered pearlite chain structure with a large porosity, and the RFC/ACF composite material is derived because of the existence of a large number of bead chain structures in the composite material. The density increases, the volume declines and the mass after being assembled into a supercapacitor as a positive electrode material decreases. The specific surface area of RFC/ACF composites is increased as compared to pure fibers. The increase in specific surface area could facilitate the diffusion of electrolyte ions in the material. Owing to the large number of bead chains, plenty of pore channels are provided for the diffusion of electrolyte ions, which is conducive to enhancing the electrochemical performance of the composite and improving the RFC/ACF composite and the specific capacitance of the material. The methods of electrochemical testing on symmetric supercapacitors (as positive electrodes) are three-electrode cyclic voltammetry, alternating current impedance and cycle stability.

The specific capacitance value of the composite material was found to be 389.2 F/g, and the specific capacitance of the electrode operating at a higher current density of 20 mA/cm2 was 11.87 F/g (the amount of the microsphere modifier added was 0.3 g). Using this material as a positive electrode to assemble into asymmetrical supercapacitor, after 2,000 cycles, the specific capacitance retention rate was 87.46 per cent, indicating excellent cycle stability performance. This result can be attributed to the fact that the modifier embedded in the fiber changes the porosity between the fibers, while improving the utilization of the carbon fibers and making it easier for electrolyte ions to enter the interior of the composites, thereby increasing the capacitance of the composites.

The modified PAN-based activated carbon fibers in the study had high specific surface area and significantly high specific capacitance, which makes it applicable as an efficient and environment-friendly absorbent, as well as an advanced electrode material for supercapacitor.

The aim of this study was to fabricate polyimide (PI)/Al₂O₃ composite films via surface modification and ion exchange techniques, and examine their properties.

The method involves hydrolyzing the PI film double surface layers in an aqueous potassium hydroxide (KOH) solution and incorporating aluminium ions (Al3+) into the hydrolyzed layers of the PI film via subsequent ion exchange, followed by a treatment of the Al3+-loaded PI films with an aqueous ammonia solution, which leads to the formation of Al(OH)₃ in the surface-modified layers. After a final thermal annealing treatment in ambient air, the Al(OH)₃ decomposes to Al₂O₃, and forms composite layers on both surfaces of the re-imidized PI film.

The PI/Al₂O₃ composite film obtained with a 6 hours of KOH treatment exhibited excellent thermal stability, good mechanical properties and better electric breakdown strength and corona-resistance properties than the pristine PI film.

The method for obtaining the composite films in this paper is worth consideration, but additional research will be needed. Furthermore, this method is of general importance for the fabrication of composite PI films with tailored properties.

This study showed that surface modification and ion-exchange techniques are powerful methodologies for the fabrication of PI/Al₂O₃ composite films.

The purpose of this paper is to investigate the effect of different soldering temperatures on the performance of chip-on-board (COB) light sources during vacuum reflow soldering.

First, the influence of the void ratio of the COB light source on the steady-state voltage, luminous flux, luminous efficiency and junction temperature has been explored at soldering temperatures of 250°C, 260°C, 270°C, 280°C and 290°C. The COB chip has also been tested for practical application and aging.

The results show that when the soldering temperature is 270°C, the void ratio of the soldering layer is only 5.1%, the junction temperature of the chip is only 76.52°C, and the luminous flux and luminous efficiency are the highest, and it has been observed that the luminous efficiency and average junction temperature of the chip are 107 lm/W and 72.3°C, respectively, which meets the requirements of street lights. After aging for 1,080 h, the light attenuation is 84.64% of the initial value, which indicates that it has higher reliability and longer life.

It can provide reference data for readers and people in this field and can be directly applied to practical engineering.