Removal of residual pesticide, fenitrothion, in vegetables by using ozone microbubbles generated by different methods

The effect of pre-treatments on atrazine removal from source water by microbubble ozonation

Ozone-based advanced oxidation processes (AOPs) have emerged a promising avenue for water treatment, offering effective removal of micropollutants. Recent research underscores the potential of ozone microbubbles to enhance ozone mass transfer during water treatment, particularly when combined with pre-treatment steps. This study aimed to evaluate the efficacy of three different combined processes (chlorine/KMnO4/PAC pre-treatment followed by ozonation) in removing atrazine, a common micropollutant from natural source water. Results revealed that all combined processes achieved higher atrazine removal rates compared to individual pre-treatment or ozonation methods. Notably, the highest atrazine removal rates were observed under alkaline pH conditions, with treatment outcomes influenced by oxidant dose and pH levels. Among the combined processes, chlorine pre-treatment followed by ozonation emerged as the most effective approach, achieving a removal rate of 59.7% that exceeded the sum of individual treatments. However, this treatment efficacy was affected by water quality parameters, particularly the presence of organic matter and elevated ammonia nitrogen concentration (> 0.5 mg/L). This study highlights the potential for utilizing ozone micro/nanobubbles to enhance ozone mass transfer and offers valuable insights for optimizing the combined application of pre-treatment and ozonation strategies for efficient atrazine removal from natural water sources.

Effects of hyperoxia during oxygen nanobubble treatment on innate immunity, growth performance, gill histology, and gut microbiome in Nile tilapia, Oreochromis niloticus

Oxygen nanobubble (NB-O2) technology has been introduced to the aquaculture industry in recent years. This treatment usually results in a tremendously high level of dissolved oxygen (DO) in the water. However, little is known about the possible negative effects of hyperoxia due to NB-O2 treatment (hyper-NB-O2) on farmed fish. Here, we investigated i) the effect of short-term hyper-NB-O2 exposure (single treatment) on the innate immunity in Nile tilapia, Oreochromis niloticus, and ii) the effect of long-term hyper-NB-O2 exposure (26-day treatments) on survival, growth performance, gill histology, and gut microbiome in Nile tilapia. A single treatment with NB-O2 for 10 min in 50 L of water resulted in 24.2 ± 0.04 mg/L DO (approximately 2-3 × 107 nanoscale oxygen bubbles/mL). This treatment did not result in differences in expression of several immune-related genes (e.g., TNF-α, LYZ and HPS70) in various tissues (e.g., gill, head kidney, and spleen) compared to the non-treated control. Over a 26-day period of exposure, no significant differences were observed in survival and growth performance of the fish, but minor histological changes were occasionally noted on the gills. Analysis of the gut microbiome revealed a significant increase in the genera Bosea, Exiguobacterium, Hyphomicrobium, and Singulisphaera in the group receiving NB-O2. Moreover, no signs of "gas bubble disease" were observed in the fish throughout the duration of the experiment. Overall, these results suggest that both short- and long-term hyper-NB-O2 exposure appears to be benign and has no obvious adverse effects on fish.

Inactivating Salmonella Enteritidis on shell eggs by using ozone microbubble water

The major pathogen associated with eggs is Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) and chlorine washing is the most widely used for sanitization. Microbubble, a novel technique and able to operate in large quantity, has been presented to be an alternative method. Thus, microbubble water combining with ozone (OMB) was applied to disinfect S. Enteritidis spiked on shells at 10⁷ cells per egg. OMB was generated by injecting ozone into a Nikuni microbubble system, then delivered into 10 L of water. After 5, 10, or 20 min of activation time, the eggs were placed into OMB and washed for 30 or 60 s. The controls involved unwashed, water washing, ozone only, and microbubble only (MB). The highest reduction, 5.19 log CFU/egg, was achieved by the combination of 20-min activation and 60-s washing, which was used for following tests of large water quantities. Comparing with the unwashed control, 4.32, 3.73 and 3.07 log CFU/egg reductions were achieved in 25, 80, and 100 L of water, respectively. The other system, Calpeda, with higher motor power was tested in 100 L and obtained a reduction of 4.15 log CFU/egg. The average diameter of bubbles generated by Nikuni and Calpeda pump systems were 29.05 and 36.50 μm, respectively, which both were within the microbubble definition of ISO. Much lower reductions, around 1-2 log₁₀ CFU/egg, were shown with the treatments of ozone only and MB by the same operative parameters. After 15-day storage at ambient temperature, the OMB-treated eggs showed similar sensory quality with the unwashed ones. This is the first study demonstrating that OMB effectively inactivates S. Enteritidis on shell eggs in large quantity of water and does not diminished the sensory characteristics of eggs. Furthermore, bacterial population was under the detection limit in the OMB-treated water.

Microbubbles in Food Technology

Microbubbles are largely unused in the food industry yet have promising capabilities as environmentally friendly cleaning and supporting agents within products and production lines due to their unique physical behaviors. Their small diameters increase their dispersion throughout liquid materials, promote reactivity because of their high specific surface area, enhance dissolution of gases into the surrounding liquid phase, and promote the generation of reactive chemical species. This article reviews techniques to generate microbubbles, their modes of action to enhance cleaning and disinfection, their contributions to functional and mechanical properties of food materials, and their use in supporting the growth of living organisms in hydroponics or bioreactors. The utility and diverse applications of microbubbles, combined with their low intrinsic ingredient cost, strongly encourage their increased adoption within the food industry in coming years.

Interactions between O2 Nanobubbles and the Pulmonary Surfactant in the Presence of Inhalation Medicines

A dispersion of oxygen nanobubbles (O2-NBs) is an extraordinary gas-liquid colloidal system where spherical gas elements can be considered oxygen transport agents. Its conversion into inhalation aerosol by atomization with the use of nebulizers, while maintaining the properties of the dispersion, gives new opportunities for its applications and may be attractive as a new concept in treating lung diseases. The screening of O2-NBs interactions with lung fluids is particularly needed in view of an O2-NBs application as a promising aerosol drug carrier with the additional function of oxygen supplementation. The aim of the presented studies was to investigate the influence of O2-NBs dispersion combined with the selected inhalation drugs on the surface properties of two types of pulmonary surfactant models (lipid and lipid-protein model). The characteristics of the air-liquid interface were carried out under breathing-like conditions using two selected tensiometer systems: Langmuir-Wilhelmy trough and the oscillating droplet tensiometer. The results indicate that the presence of NBs has a minor effect on the dynamic characteristics of the air-liquid interface, which is the desired effect in the context of a potential use in inhalation therapies.

Organic wastes bioremediation and its changing prospects

Increasing inappropriate anthropogenic activities and industrialization have resulted in severe environmental pollution worldwide. Their effective treatment is vital for general health concerns. Depending on the characteristics of pollutants, the severity of pollution may differ. For sustainable treatment of polluted environments, bioremediation is accepted as the most efficient, economical, and environmentally friendly method hence largely preferred. However, every bioremediation technique has its own unique advantages and limitations due to its defined applications criteria. In bioremediation, microorganisms play a decisive role in detoxification by degrading, mineralizing and accumulating various forms of harmful and biodegradable pollutants from the surroundings and transforming them into less lethal forms. Bioremediation is performed ex-situ or in-situ, based on location of polluted site as well as characteristics, type and strength of the pollutants. Furthermore, the most popular methodologies for bioremediation include bioaugmentation, biostimulation, bioattenuation among others which depend on the prevailing environmental factors into the microbial system. Implementing them appropriately and effectively under ex-situ or in-situ method is extremely important not only for obtaining efficient treatment but also for the best economic, environmental, and social impacts. Therefore, this review aims to analyze various bioremediation methods for organic pollutants remediation from soil/sediments and wastewater, their strength, limitation, and insights for the selection of appropriate bioremediation techniques based on nature, types, degree, and location of the pollution. The novelty aspect of the article is to give updates on several key supporting technologies which have recently emerged and exhibited great potential to enhance the present bioremediation efficiency such as nanobubble, engineered biochar, mixotrophic microalgae, nanotechnology etc. Moreover, amalgamation of these technologies with existing bioremediation facilities are significantly changing the scenario and scope of environmental remediation towards sustainable bioremediation.

Antibacterial Efficacy and Physiochemical Effects of Ozone Microbubble Water on Tomato

The consumption of fresh produce is steadily increasing and chlorine washing is the most commonly used method of disinfecting fresh produce. However, chlorine washing possesses a potential risk. Hence, this study used ozone microbubble (OMB) water to disinfect Salmonella Enteritidis, S. Typhimurium, Staphylococcus aureus, and Escherichia coli on tomatoes. After injecting ozone into the microbubble generator, OMB was fulfilled in a 10 L tank for 10 or 20 min. The inoculated tomatoes were washed for 30 or 60 s. Control groups included unwashed, water-washed, microbubble-only, and ozone-only. The microbial populations were significantly lower on the OMB-treated tomatoes than controls (p < 0.05), but not between various fulfilling or treatment time (p > 0.05). When tomatoes were treated with OMB with 10 min fulfilling and 30-s washing, the differences of tested bacteria and water washing, ozone-only, and microbubble-only were: S. Enteritidis: 4.11, 3.37, 2.54 log CFU/tomato; S. Typhimurium: 4.83, 4.50, 2.78 log CFU/tomato; E. coli: 4.31, 4.08, 2.09 log CFU/tomato; S. aureus: 4.12, 3.93, 2.82 log CFU/tomato. In addition, significant higher ozone concentrations and conductivity were detected in OMB water than other groups (p < 0.05). Color, texture, and sensory characteristics of the OMB-treated tomatoes were not significantly different from other groups (p > 0.05). This study demonstrated that OMB effectively inactivated bacteria on tomatoes and did not affect the physical and sensory characteristics of tomatoes.

Generation methods, stability, detection techniques, and applications of bulk nanobubbles in agro-food industries: a review and future perspective

Nanobubble (NB) technologies have received considerable attention for various applications due to their low cost, eco-friendliness, scale-up potential, process control, and unique physical characteristics. NB stands for nanoscopic gaseous cavities, typically <1 μm in diameter. NBs can exist on surfaces (surface or interfacial NBs) and be dispersed in a bulk liquid phase (bulk NBs). Compared to the microbubbles, NBs exhibit high specific surface area, negative surface charge, and better adsorption. Bulk NBs can be generated by hydrodynamic/acoustic cavitation, electrolysis, water-solvent mixing, nano-membrane filtration, and so on. NBs exhibit extraordinary longevity compared to microbubbles, prompting the interest of the scientific community aiming for potential applications including medicine, agriculture, food, wastewater treatment, surface cleaning, and so on. Based on the limited amount of research work available regarding the influence of NBs on food matrices, further research, however, needs to be done to provide more insights into its applications in food industries. This review provides an overview of the generation methods for NBs, techniques to evaluate them, and a discussion of their stability and several applications in various fields of science were discussed. However, recent studies have revealed that, despite the many benefits of NB technologies, several NB generating approaches are still limited in their application in specific agro-food industries. Further study should focus on process optimization, integrating various NB generation techniques/combining with other emerging technologies in order to achieve rapid technical progress and industrialization of NB-based technologies.HighlightsNanobubbles (NBs) are stable spherical entities of gas within liquid and are operationally defined as having diameters less than 1 µm.Currently, various reported theories still lack the ability to explain the evidence and stability of NBs in water, numerous NB applications have emerged due to the unique properties of NBs.NB technologies can be applied to various food and dairy products (e.g. yogurt and ice cream) and other potential applications, including agriculture (e.g. seed germination and plant growth), wastewater treatment, surface cleaning, and so on.

Microbubbles for Effective Cleaning of Metal Surfaces Without Chemical Agents

Traditional cleaning methods involving surfactants and ultrasound generate large amounts of wastewater. Microbubbles offer a more eco-friendly technology for interface cleaning. Here, we explored the efficiency of microbubbles for cleaning oil from metal surfaces. Air microbubbles at concentrations as high as 10⁶ particles/mL were generated by hydrodynamic cavitation. Under optimal conditions, cleaning efficiencies for the removal of oil from carbon-steel and stainless-steel surfaces were 78.5 and 49.8% after 15 min, respectively, compared to only 6.5 and 9.9% without microbubbles. Additionally, combining microbubble treatment with the ultrasonic method achieved a higher efficiency than ultrasonic cleaning alone, achieving an efficiency of 85.5% after 3 min compared to 69.0%. The mechanism of microbubble cleaning was determined using a fluorescence observation system, and a model was established to describe the cleaning process. The use of microbubbles produced less emulsified oil wastewater because the oil that attaches to the microbubble surface floats with the bubbles to the surface of the cleaning water, where it can be removed, allowing for water recycling. This novel microbubble cleaning technology, which both enhances cleaning efficiency and reduces wastewater production, represents a viable and eco-friendly option for degreasing processes.

Decontamination of fenitrothion from aqueous solutions using rGO/MoS2/Fe3O4 magnetic nanosorbent: synthesis, characterization and removal application

In the present work, rGO/MoS2/Fe3O4 nanocomposite was synthesized and after confirmation of the structure by FTIR, XRD, and FESEM techniques, its performance as nanosorbent was investigated for the removal of fenitrothion pesticide from the aqueous media. The parameters affecting the removal process including agitation time, pH of the reaction medium, adsorbent content, initial analyte concentration as well as desorption parameters were investigated and optimized. Under optimum conditions (pH = 7, adsorbent amount: 30 mg, adsorption and desorption time: 5 min, eluent type and volume: 0.01 M ethanol-acetic acid and 4 mL), the synthesized adsorbent was able to remove fenitrothion pesticide up to 98% with an adsorption capacity of 33.4 mg/g. By investigation of the line equation and the correlation coefficient value, it was found that the adsorption process, in this study, follows the Langmuir model.

Impact of sonolytic ozonation (O3/US) on degradation of pesticide residues in fresh vegetables and fruits: Case study of Faisalabad, Pakistan

High pesticide residues in fresh produce is a serious food safety issue. This study was aimed at assessing the pesticides residues in some important vegetables and fruits marketed in Faisalabad, Pakistan and the impact of sonolytic ozonation (O₃/US) treatment in removing these contaminants. From a short grower's survey, five registered and mostly used pesticides (acetamiprid, carbendazim, imidacloprid, thiacloprid and thiamethoxam) were identified. A time optimization trial of O₃/US application (05, 10 and 15 min) on okra, showed that 10 min treatment significantly reduced three identified chemicals (thiamethoxam 100 %, imidacloprid and thiacloprid 97.17 %), without any adverse effect on its quality. In follow up trial, five fresh vegetables (cauliflower, chillies, cucumber, spinach and tomato) three fresh fruits (grapes, guava and peach) collected from three markets of Faisalabad, were pooled together to have uniform samples. Vegetables and fruits were treated with O₃/US for 10 and 6 min, respectively, along with control (simple tap wash) for determining the impacts on pesticides degradation. Samples were processed for extraction, clean up and analysis using HPLC-UV-Vis in isocratic mode. The data revealed the presence of five mentioned chemicals, with an accumulative mean residue of 9.006 and 1.921 µg/g in tested vegetables and fruits, respectively. After subjecting to O₃/US, the accumulative chemical residues were reduced to 3.214 µg/g (64.313 %) and 1.064 (44.6 %) in treated vegetables and fruits respectively. Irrespective of fresh produce, the mean residues of thiamethoxam, imidachloprid, acetamiprid and thiachloprid and carbendazim were reduced by 99.3 %, 52.6 %, 65.2 %, 87.3 % and 72% respectively. It was concluded that sonolytic ozonation treatment was effective in significant reduction of pesticide residues from vegetables and fruits and thus can be employed as a good food safety practice at culinary level to reduce the associated health hazardous risks.

The Application Method of Nanobubble Conveyor on the Effect of Preventive Oral Hygiene

There are various methods to generate nanobubbles, and in this study, we experimented using a nanobubble generator with a high-density of stainless steel mesh nozzle to deliver nanobubble water (normal water and two kinds of mouthwash) stream through a tooth tray to clean bacteria coated on the denture. It showed that with various combinations of motor speed settings and pore diameters, a clearing rate of 95% or more could be achieved, while in some combinations, a clearing rate of 100% was possible. This confirmed the plaque removing the function of the nanobubble water streams. The motor speed setting of the nanobubble generator directly influenced the flow velocity and nanobubble diameter of the water stream. However, the nanobubble dimensions were found to have a significant impact on plaque removal. The bubble diameters and plaque removal efficacy were as follows: the smaller the diameter, the slower the flow velocity and the better the plaque removal. The nanobubble formation of mouthwash was better on plaque removal, compared with the soaking method. From these results, we theorized that plaque removal is influenced by the dimension of nanobubbles; smaller bubble diameter led to improved plaque removal efficacy.

Study on oral hygiene by nanobubbles from high-density nozzle

An experiment was performed on oral bacteria removal using the design variables, which included the three-segment rotor speed of the testing device and three types of stainless steel meshes (with different layers). The overall hygienic results showed an effect of up to 95% bacteria removal, and some combinations had 100% hygienic effect. The study proposed that the use of nanobubble generated by a high-density stainless-steel mesh-manufactured nozzle removes dental bacteria. In addition, the device could also be used for auxiliary oral hygiene to decrease the frequency of future medical visits due to periodontal diseases or to enable the device to assist patients with severe periodontal disease more conveniently for oral hygiene.

Efficacy of using oxygen microbubble device for facultative anaerobe removal

Patients with serious gingivitis or periodontal diseases suffer from receding gums. Brushing teeth with a toothbrush may result in bleeding gums and new wounds, which increases the difficulty of removing facultative anaerobes from gum pockets, to decrease the damage inflicted on gums, this study proposed a cleaning device that can generate and emit oxygen microbubbles for eliminating facultative anaerobes in the mouth cavity. In this study, the authors conducted simulations with a denture to investigate the efficacy of using this method to remove facultative anaerobes. In this research for the optimal device design, several variables were manipulated including rotation speeds of the bubble generator, different nozzle diameters, and different numbers of nozzle holes. The results revealed that the device is effective in removing facultative anaerobes; moreover, of all design variables, the number of nozzle holes was the factor having the largest effect on anaerobe removal, as it influenced the flow volume and oxygen content of the discharge: the greater the number of nozzles, the greater the flow volume, oxygen content, and efficacy of anaerobe removal.

Bubble Size and Bubble Concentration of a Microbubble Pump with Respect to Operating Conditions

The present paper describes some aspects of the bubble size and concentration of a microbubble pump with respect to flow and pressure conditions. The microbubble pump used in the present study has an open channel impeller of a regenerative pump, which generates micro-sized bubbles with the rotation of the impeller. The bubble characteristics are analyzed by measuring the bubble size and concentration using the experimental apparatus consisting of open-loop facilities; a regenerative pump, a particle counter, electronic flow meters, pressure sensors, flow control valves, a torque meter, and reservoir tanks. To control the intake, and the air flowrate upstream of the pump, a high precision flow control valve is introduced. The bubble characteristics have been analyzed by controlling the intake air flowrate and the pressure difference of the pump while the rotational frequency of the pump impeller was kept constant. All measurement data was stored on the computer through the NI (National Instrument) interface system. The bubble size and concentration are mainly affected by three operating parameters: the intake air flowrate, the pressure difference, and the water flowrate supplied to the pump. It is noted that the operating conditions that can most effectively generate microbubbles in the range of 20 to 30 micrometers are at the pressure of 5 bar and at the air flowrate ratio of 4.0 percent for the present pump. Throughout the experimental measurements, it was found that the pump efficiency changed by less than 1.2 percent, depending on the intake air supply. The performance characteristics of microbubble generation obtained by experimental measurements are analyzed and discussed in detail.

Generation of nanobubbles by ceramic membrane filters: The dependence of bubble size and zeta potential on surface coating, pore size and injected gas pressure

Generation of gaseous nanobubbles (NBs) by simple, efficient, and scalable methods is critical for industrialization and applications of nanobubbles. Traditional generation methods mainly rely on hydrodynamic, acoustic, particle, and optical cavitation. These generation processes render issues such as high energy consumption, non-flexibility, and complexity. This research investigated the use of tubular ceramic nanofiltration membranes to generate NBs in water with air, nitrogen and oxygen gases. This system injects pressurized gases through a tubular ceramic membrane with nanopores to create NBs. The effects of membrane pores size, surface energy, and the injected gas pressures on the bubble size and zeta potential were examined. The results show that the gas injection pressure had considerable effects on the bubble size, zeta potential, pH, and dissolved oxygen of the produced NBs. For example, increasing the injection air pressure from 69 kPa to 414 kPa, the air bubble size was reduced from 600 to 340 nm respectively. Membrane pores size and surface energy also had significant effects on sizes and zeta potentials of NBs. The results presented here aim to fill out the gaps of fundamental knowledge about NBs and development of efficient generation methods.

Influences of Air, Oxygen, Nitrogen, and Carbon Dioxide Nanobubbles on Seed Germination and Plant Growth

Nanobubbles (NBs) hold promise in green and sustainable engineering applications in diverse fields (e.g., water/wastewater treatment, food processing, medical applications, and agriculture). This study investigated the effects of four types of NBs on seed germination and plant growth. Air, oxygen, nitrogen, and carbon dioxide NBs were generated and dispersed in tap water. Different plants, including lettuce, carrot, fava bean, and tomato, were used in germination and growth tests. The seeds in water-containing NBs exhibited 6-25% higher germination rates. Especially, nitrogen NBs exhibited considerable effects in the seed germination, whereas air and carbon dioxide NBs did not significantly promote germination. The growth of stem length and diameter, leave number, and leave width were promoted by NBs (except air). Furthermore, the promotion effect was primarily ascribed to the generation of exogenous reactive oxygen species by NBs and higher efficiency of nutrient fixation or utilization.

Technologies and Trends to Improve Table Olive Quality and Safety

Table olives are the most widely consumed fermented food in the Mediterranean countries. Peculiar processing technologies are used to process olives, which are aimed at the debittering of the fruits and improvement of their sensory characteristics, ensuring safety of consumption at the same time. Processors demand for novel techniques to improve industrial performances, while consumers' attention for natural and healthy foods has increased in recent years. From field to table, new techniques have been developed to decrease microbial load of potential spoilage microorganisms, improve fermentation kinetics and ensure safety of consumption of the packed products. This review article depicts current technologies and recent advances in the processing technology of table olives. Attention has been paid on pre processing technologies, some of which are still under-researched, expecially physical techniques, such ad ionizing radiations, ultrasounds and electrolyzed water solutions, which are interesting also to ensure pesticide decontamination. The selections and use of starter cultures have been extensively reviewed, particularly the characterization of Lactic Acid Bacteria and Yeasts to fasten and safely drive the fermentation process. The selection and use of probiotic strains to address the request for functional foods has been reported, along with salt reduction strategies to address health concerns, associated with table olives consumption. In this respect, probiotics enriched table olives and strategies to reduce sodium intake are the main topics discussed. New processing technologies and post packaging interventions to extend the shelf life are illustrated, and main findings in modified atmosphere packaging, high pressure processing and biopreservaton applied to table olive, are reported and discussed.

Ozone as degradation agent of pesticide residues in stored rice grains

This work aimed to study the kinetics of bifenthrin and deltamethrin residues degradation in rice grains under exposure to ozone and evaluate the effect of ozonization on rice grains marketing standards. The grains sprayed with pesticides were exposed to ozone at a concentration of 3 mg L-1 and continuous flow of 1.0 L min-1 for defined periods of up to 10 h. Residues of pesticides were extracted from grains using solid liquid extraction method with low-temperature partition analyzed by gas chromatography with electron capture detection (SLE/LTP-GC/ECD). Data from residual concentrations of bifenthrin and deltamethrin, due to the ozone exposure period, were adjusted to kinetic models of zero order, first order and second order. It was observed that ozone was effective in the degradation bifenthrin and deltamethrin residues, removing 91.9% of bifenthrin and 92.7% of deltamethrin. The kinetic model that best fitted deltamethrin and bifenthrin residues degradation data by ozone, was the one of first order. The marketing standards evaluated were the water content and yield. It was observed the ozone did not alter the rice grains water content and yield.

Advances in postharvest technologies to extend the storage life of minimally processed fruits and vegetables

Minimally processed fresh produce is one of the fastest growing segments of the food industry due to consumer demand for fresh, healthy, and convenient foods. However, mechanical operations of cutting and peeling induce the liberation of cellular contents at the site of wounding that can promote the growth of pathogenic and spoilage microorganisms. In addition, rates of tissue senescence can be enhanced resulting in reduced storage life of fresh-cut fruits and vegetables. Chlorine has been widely adopted in the disinfection and washing procedures of fresh-cut produce due to its low cost and efficacy against a broad spectrum of microorganisms. Continuous replenishment of chlorine in high organic wash water can promote the formation of carcinogenic compounds such as trihalomethanes, which threaten human and environmental health. Alternative green and innovative chemical and physical postharvest treatments such as ozone, electrolyzed water, hydrogen peroxide, ultraviolet radiation, high pressure processing, and ultrasound can achieve similar reduction of microorganisms as chlorine without the production of harmful compounds or compromising the quality of fresh-cut produce.

Effective Subcritical Butane Extraction of Bifenthrin Residue in Black Tea

As a natural and healthy beverage, tea is widely enjoyed; however, the pesticide residues in tea leaves affect the quality and food safety. To develop a highly selective and efficient method for the facile removal of pesticide residues, the subcritical butane extraction (SBE) technique was employed, and three variables involving temperature, time and extraction cycles were studied. The optimum SBE conditions were found to be as follows: extraction temperature 45 °C, extraction time 30 min, number of extraction cycles 1, and in such a condition that the extraction efficiency reached as high as 92%. Further, the catechins, theanine, caffeine and aroma components, which determine the quality of the tea, fluctuated after SBE treatment. Compared with the uncrushed leaves, pesticide residues can more easily be removed from crushed leaves, and the practical extraction efficiency was 97%. These results indicate that SBE is a useful method to efficiently remove the bifenthrin, and as appearance is not relevant in the production process, tea leaves should first be crushed and then extracted in order that residual pesticides are thoroughly removed.

Remediation of oil-contaminated sand with self-collapsing air microbubbles

In this study, a novel chemical-free approach for cleaning oil-contaminated sand with self-collapsing air microbubbles (MBs) with diameter less than 50 μm was developed without the use of chemicals, such as surfactants and alkalis. Diesel and rotary-vane pump oil-contaminated fine and medium sands were treated with MBs to study the effect of oil viscosity and sand grain size on oil removal with MBs. About 95 % of diesel removal was achieved for 24 h old 10 % (w/w) diesel-contaminated medium sand in contrast to only 70 % removal from fine sand after 40-min treatment with MBs. While rotary-vane pump oil removal exceeds that of diesel after 40-min treatment with MBs, combination of mechanical stirring with MBs significantly enhanced the oil removal rate, whereby 95 % diesel removal was achieved from fine sand in 30 min in contrast to only 52 % diesel removal with MBs alone. A possible MBs cleaning mechanism for oil-contaminated sand was also proposed. This study provides experimental evidence for the applicability of self-collapsing MBs as a novel chemical-free approach for cleaning oil-contaminated sand.

Aqueous ozone solutions for pesticide removal from potatoes

The presence of pesticide residues in potatoes is of concern because of the potential impact to human health due to the high consumption of this vegetable. In this study, aqueous solutions with and without ozone saturation as postharvest wash treatment at pH 4.0, 7.0, and 9.0 were tested to remove chlorothalonil from potatoes. The method used for pesticide analysis has been validated, presenting recovery values of 94–103%, with variations in the repeatability coefficients of ≤10.6%, and a quantification limit of 0.05 mg kg−1. Regardless of pH, treatment with aqueous ozone solutions removed 70–76% of the pesticide present in the potato. In the no-ozone treatments, the percentage average removal of chlorothalonil residues in potatoes was only 36%. Over 24 days of storage, the quality of potatoes washed with aqueous ozone solutions was not significantly different from those washed with pure water.

Combining microfluidic devices with coarse capillaries to reduce the size of monodisperse microbubbles

In this work, a major advance for the controlled production of monodisperse microbubbles, which are a key constituent in many advanced technologies, has been invented using simple microfluidic technology.

Recent developments in minimal processing: a tool to retain nutritional quality of food

The modernization during the last century resulted in urbanization coupled with modifications in lifestyles and dietary habits. In the same era, industrial developments made it easier to meet the requirements for processed foods. However, consumers are now interested in minimally processed foods owing to increase in their awareness to have fruits and vegetables with superior quality, and natural integrity with fewer additives. The food products deteriorate as a consequence of physiological aging, biochemical changes, high respiration rat,e and high ethylene production. These factors contribute substantially to discoloration, loss of firmness, development of off-flavors, acidification, and microbial spoilage. Simultaneously, food processors are using emerging approaches to process perishable commodities, along with enhanced nutritional and sensorial quality. The present review article is an effort to utilize the modern approaches to minimize the processing and deterioration. The techniques discussed in this paper include chlorination, ozonation, irradiation, photosensitization, edible coating, natural preservative use, high-pressure processing, microwave heating, ohmic heating, and hurdle technology. The consequences of these techniques on shelf-life stability, microbial safety, preservation of organoleptic and nutritional quality, and residue avoidance are the limelight of the paper. Moreover, the discussion has been made on the feasibility and operability of these techniques in modern-day processing.

Ozone microbubble treatment at various water temperatures for the removal of residual pesticides with negligible effects on the physical properties of lettuce and cherry tomatoes

In this study, the effects of ozone microbubbles (OMCB) treatment at various water temperatures on the removal of residual fenitrothion (FT) pesticides and on the physical properties of lettuce and cherry tomatoes was examined. The residual FT percentage in lettuce and cherry tomatoes was shown decreased by using higher water temperatures, particularly at 30 °C, resulting in a decrease within the range of 32% to 52%, after the 20-min treatment. In addition, bubbling OMCB treatment did not alter the color and pulling strength of lettuce and cherry tomatoes. These results indicate that bubbling OMCB treatment at 30 °C is a highly effective method for the removal of FT residues in lettuce and cherry tomatoes, with relatively little effect on crop quality.

PRACTICAL APPLICATION

The bubbling OMCB has a potential of reducing the FT reduces on vegetables with no adverse effect on the sensory quality of vegetables.

Removal of chloropyrifos ethyl, tetradifon and chlorothalonil pesticide residues from citrus by using ozone

The removal of chloropyrifos ethyl, tetradifon and chlorothalonil pesticide residues from the lemon, orange and grapefruit matrices were achieved by ozonation. All of chlorothalonil residues adsorbed onto the orange matrix were completely removed after 5 min ozonation. The highest removal percentages of tetradifon and chloropyrifos ethyl were achieved as 98.6 and 94.2%, respectively for the lemon and grapefruit matrices. All of diffused chlorothalonil and chloropyrifos ethyl residues were completely removed from both orange and grapefruit matrices after 5 min ozonation. Increasing of applied ozone dosage was not significantly effect on the removal percentages of pesticides whereas increasing of ozonation temperature caused a negative effect on the removal percentages of pesticides. The washing of the matrices with tap water was not as effective as ozonation in the removal of residual pesticides. Our results show that ozone treatment has a great potential for removing of residual pesticides from lemon, orange and grapefruit matrices.