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The exploration of space is becoming more feasible, and with this comes the possibility of performing fermentations in microgravity. Our study explores the potential effects of microgravity on a standard brewing model fermentation. As the fermentation of barley wort has been studied for centuries, there is an established foundation of knowledge with which to compare any changes that occur under microgravity. A modified ASBC miniature fermentation protocol (Yeast-14) was conducted within a Yuri 2.0 microgravity chamber to examine the response of Saccharomyces pastorianus to simulated microgravity conditions. Our findings reveal that yeast exhibited accelerated growth rates under microgravity compared to standard conditions. Additionally, the microgravity environment led to significantly lower levels of volatile compounds such as isoamyl acetate and 2-phenethyl acetate in the final product. Further genetic analysis showed significant downregulation of the ATF2 gene in the control group, potentially the mechanism behind the observed decrease in volatile compounds. These results show that while fermentation under microgravity is likely to eventually be commonplace, there may be changes in rate and gene expression that are beneficial or detrimental to the final product depending upon the desired characteristics. [ABSTRACT FROM AUTHOR]

Belgian Saisons and Lambics are two well‐known examples in the brewing industry of mixed fermentations, combination of two or more yeast and/or bacteria strains. The purpose of this study was to determine the impact different pitch rates of Saccharomyces cerevisiae (traditional brewing yeast) and S. cerevisiae var. diastaticus (a variant associated with Belgian styles) had on the fermentation kinetics and concentration of the volatile compounds in the finished beers. A series of brews were performed utilizing ratios of S. cerevisiae and diastaticus. The fermentations were heavily monitored, and a model was used to fit fermentation variables. It was found that mixed fermentations produced behaviors that were predictable and proportional to the mixture ratios. As expected, the pure cultural fermentations of diastaticus had a slower fermentation midpoint (M) at 45.45 h versus 28.28 h for S. cerevisiae with the mixed ones falling in between the two. Flavor and aroma play a key role in the acceptability of beer. The mixed fermentations showed a combination of the two different yeast strains aromatic profiles. When combined, there was a strong linearity between alcohols (R2 = 0.94), esters (R2 = 0.89), and the overall total (R2 = 0.91) volatile compounds. Practical Application: Modeling is a widely utilized tool in several different fields. The purpose of this research is to apply modeling techniques to describe the fermentation speed and flavor profile of a mixed fermentation between S. cerevisiae and diastaticus. The equations from this data can be used by brewers for product development purposes to make beers with certain flavor profiles within a desired timeframe. [ABSTRACT FROM AUTHOR]

Why was the work done: Diastatic variants of Saccharomyces cerevisiae are unusual in producing an extracellular glucoamylase which enables the breakdown of starch to fermentable sugars. Diastatic S. cerevisiae has long been viewed negatively as a contaminant of especially beer packaged in cans or bottles. However, this view is being reconsidered due to the opportunities that diastatic strains present for niche fermented products and distillation applications. What are the main findings: This review highlights the utilisation of diastatic S. cerevisiae for its flavour potential, and processing applications in the brewing, distilling, and biofuel industries. Further, genetic differences are compared with non-diastatic strains of S. cerevisiae, together with commonly employed and emerging methods of detection. Why is the work important: Diastatic yeast strains can be used to create flavour profiles that resemble traditional beverages and can be used to achieve fermentation with higher attenuation. This offers greater fermentation efficiency in, for example, the development of low-calorie beers. Additionally, the ability of diastatic strains of S. cerevisiae to convert non-fermentable oligosaccharides to fermentable sugars enables applications that range from novel beverages using unusual raw materials to more efficient distillation and biofuel production. The negative attributes that are associated with diastatic S. cerevisiae yeasts can be managed through co-inoculation or hybridisation with standard strains. [ABSTRACT FROM AUTHOR]

The requirement of a large input amount (500 ng) for Nanopore direct RNA‐seq presents a major challenge for low input transcriptomic analysis and early pathogen surveillance. The high RNA input requirement is attributed to significant sample loss associated with library preparation using solid‐phase reversible immobilization (SPRI) beads. A novel solid‐phase catalysis strategy for RNA library preparation to circumvent the need for SPRI bead purification to remove enzymes is reported here. This new approach leverages concurrent processing of non‐polyadenylated transcripts with immobilized poly(A) polymerase and T4 DNA ligase, followed by directly loading the prepared library onto a flow cell. Whole transcriptome sequencing, using a human pathogen Listeria monocytogenes as a model, demonstrates this new method displays little sample loss, takes much less time, and generates higher sequencing throughput correlated with reduced nanopore fouling compared to the current library preparation for 500 ng input. Consequently, this approach enables Nanopore low‐input direct RNA‐seq, improving pathogen detection and transcript identification in a microbial community standard with spike‐in transcript controls. Besides, as evident in the bioinformatic analysis, the new method provides accurate RNA consensus with high fidelity and identifies higher numbers of expressed genes for both high and low input RNA amounts. [ABSTRACT FROM AUTHOR]

Biopolymer-based nanoparticles, prepared from stearic acid-chitosan derivative, sodium caseinate (NaCas) and oxidized dextran (Odex), have been shown to have high biocompatibility and exceptional gastrointestinal (GI) stability. However, the mucoadhesive properties of such nanoparticles have yet to be analyzed. Therefore, interactions between the nanoparticles and mucin, the major protein of the mucus layer, were evaluated through rheological studies, quartz crystal microbalance with dissipation (QCM-D) analysis, and adsorption testing. There was an increase in the elastic and viscous properties of mucin when complexed with the nanoparticles during the frequency sweep, denoting rheological synergism. The nanoparticles exhibited rapid decreases in frequency and increases in dissipation during the QCM-D analysis, denoting successful adsorption onto the mucin layer. Following adsorption testing, peak adsorption (91 %) was found to be at a ratio of 1:4 at mucin/nanoparticles (weight/weight). Once the role of the nanoparticles' mucoadhesive properties in GI stability was determined, astaxanthin (ASTX) was utilized as a model nutrient for enhanced bioavailability via encapsulation. The effect of encapsulation on ASTX was determined through measuring particulate properties. Encapsulated ASTX exhibited enhanced antioxidant activity compared to free ASTX in ABTS and DPPH antioxidant assays. This study suggests that the as-prepared biopolymer nanoparticles exhibit mucoadhesive properties that could beneficially interact with the mucus layer of the GI tract. Given their enhanced mucoadhesive properties, the nanoparticles make an excellent candidate for the encapsulation of nutrients with low bioavailability such as the lipophilic ASTX. [ABSTRACT FROM AUTHOR]

Viable pathogenic bacteria are major biohazards that pose a significant threat to food safety. Despite the recent developments in detection platforms, multiplex identification of viable pathogens in food remains a major challenge. A novel strategy is developed through direct metatranscriptome RNA-seq and multiplex RT-PCR amplicon sequencing on Nanopore MinION to achieve real-time multiplex identification of viable pathogens in food. Specifically, this study reports an optimized universal Nanopore sample extraction and library preparation protocol applicable to both Gram-positive and Gram-negative pathogenic bacteria, demonstrated using a cocktail culture of E. coli O157:H7, Salmonella enteritidis , and Listeria monocytogenes , which were selected based on their impact on economic loss or prevalence in recent outbreaks. Further evaluation and validation confirmed the accuracy of direct metatranscriptome RNA-seq and multiplex RT-PCR amplicon sequencing using Sanger sequencing and selective media. The study also included a comparison of different bioinformatic pipelines for metatranscriptomic and amplicon genomic analysis. MEGAN without rRNA mapping showed the highest accuracy of multiplex identification using the metatranscriptomic data. EPI2ME also demonstrated high accuracy using multiplex RT-PCR amplicon sequencing. In addition, a systemic comparison was drawn between Nanopore sequencing of the direct metatranscriptome RNA-seq and RT-PCR amplicons. Both methods are comparable in accuracy and time. Nanopore sequencing of RT-PCR amplicons has higher sensitivity, but Nanopore metatranscriptome sequencing excels in read length and dealing with complex microbiome and non-bacterial transcriptome backgrounds. [ABSTRACT FROM AUTHOR]

With superior physicochemical properties, soft engineered nanoparticles (sENP) (protein, carbohydrate, lipids and other biomaterials) are widely used in foods. The preparation, functionalities, applications, transformations in gastrointestinal (GI) tract, and effects on gut microbiota of sENP directly incorporated for ingestion are reviewed herein. At the time of this review, there is no notable report of safety concerns of these nanomaterials found in the literature. Meanwhile, various beneficial effects have been demonstrated for the application of sENP. To address public perception and safety concerns of nanoscale materials in food, methodologies for evaluation of physiological effects of nanomaterials are reviewed. The combination of these complementary methods will be useful for the establishment of a comprehensive risk assessment system. [ABSTRACT FROM AUTHOR]

Summary: Quorum sensing (QS) exists widely among bacteria, enabling a transition to multicellular behaviour after bacterial populations reach a particular density. The coordination of multicellularity enables biotechnological application, dissolution of biofilms, coordination of virulence, and so forth. Here, a method to elicit and subsequently disperse multicellular behaviour among QS‐negative cells is developed using magnetic nanoparticle assembly. We fabricated magnetic nanoparticles (MNPs, ∼5 nm) that electrostatically collect wild‐type (WT) Escherichia coli BL21 cells and brings them into proximity of bioengineered E. coli [CT104 (W3110 lsrFG− luxS− pCT6 + pET‐DsRed)] reporter cells that exhibit a QS response after receiving autoinducer‐2 (AI‐2). By shortening the distance between WT and reporter cells (e.g., increasing local available AI‐2 concentrations), the QS response signalling was amplified four‐fold compared to that in native conditions without assembly. This study suggests potential applications in facilitating intercellular communication and modulating multicellular behaviours based on user‐specified designs. [ABSTRACT FROM AUTHOR]

Traditional foods (TFs) inherit a long history and colorful cultures and are closely bound with the dietary patterns of indigenous people. They are either homemade or commercially made and purchased from local food outlets, which provide distinctive textural and sensory properties, nutritional values, and bioactive functions. However, the science and wisdom of TFs are not thoroughly understood by local people in their historical context. Today's scientific knowledge and technical capabilities provide opportunities for scientists, industries, and consumers to understand the scientific ingenuity behind TFs, which may significantly promote the transition of TFs from homemade to scaled and standardized manufacturing with global availability and acceptance. In addition, the science of TFs may open new vistas for developing modern foods and new lifestyles. This review summarizes and provides insights into the science of TFs, covering food chemistry, food quality, food safety, health function, food processing, and its implications for future food systems. • Modern science revealed the sciences and benefits of TFs. • Scientific knowledge promoted TFs into global availability. • Science of TFs inspired the development of modern foods and new lifestyles. • Advanced methodologies provide new opportunities in TF studies. [ABSTRACT FROM AUTHOR]

Determination of the minimum free chlorine concentration needed to prevent pathogen survival/cross-contamination during produce washing is essential for the development of science-based food safety regulations and practices. Although the trend of chlorine concentration-contact time on pathogen inactivation is generally understood, specific information on chlorine and the kinetics of pathogen inactivation at less than 1.00 s is urgently needed by the produce processing industry. However, conventional approaches to obtain this critical data have been unable to adequately measure very rapid responses. This paper reports our development, fabrication, and test of a novel microfluidic device, and its application to obtain the necessary data on pathogen inactivation by free chlorine in produce wash solution in times as short as 0.10 s. A novel microfluidic mixer with the capability to accurately determine the reaction time and control the chlorine concentration was designed with three inlets for bacterial, chlorine and dechlorinating solutions, and one outlet for effluent collection. The master mold was fabricated on a silicon wafer with microchannels via photopolymerization. Polydimethylsiloxane replicas with patterned microchannels were prototyped via soft lithography. The replicas were further assembled into the micromixer on glass via O 2 plasma treatment, and the inlets were connected to a syringe pump for solution delivery. To determine the kinetics of free chlorine on pathogen inactivation, chlorine solutions of varying concentrations were first pumped into the micromixer, together with the addition of bacterial suspension of Escherichia coli O157:H7 through a separate inlet. This was followed by injection of dechlorinating solution to stop the chlorine-pathogen reaction. The effluent was collected and the surviving bacteria cells were enumerated using a modified ‘Most Probable Number’ method. Free chlorine concentration was determined using a standard colorimetric method. The contact time was experimentally set by adjusting the solution flow rate, and was estimated by computational fluid dynamics modeling. Results showed that 1) pathogen inactivation was significantly affected by free chlorine concentration (P < 0.0001) and subsecond reaction time (P < 0.0001) and their interactions (P < 0.0001); and 2) the current industry practice of using 1.0 mg/L free chlorine will require more than 1.00 s total contact to achieve a 5-log 10 reduction in an E. coli O157:H7 population, whereas a 10.0 mg/L free chlorine solution will achieve 5-log 10 reduction in as little as 0.25 s. Information obtained from this study will provide critical insight on kinetics of bacterial inactivation for a broad range of sanitizers and produce wash operational conditions, thus facilitating the development and implementation of science-based food safety regulations and practices for improving food safety. [ABSTRACT FROM AUTHOR]

Sensor-based chemical analyses commonly enlist either the molecular recognition capabilities of biology (e.g., enzyme biosensors) or advanced information processing algorithms (e.g., the electronic nose). Here, a hybrid approach is proposed in which an enzyme is used to 'filter' chemical information and write this information to a film which then serves as a permanent storage medium that can be 'read' repeatedly, interactively, and by multiple sensor modalities. This approach is demonstrated by analyzing common dietary phenols that are reported to offer health benefits. Specifically, the enzyme tyrosinase is used to convert these phenols into reactive quinones that graft (i.e., write) to a chitosan film. Grafting can be detected by optical, mechanical, and electrochemical sensors. Importantly, grafting confers redox activity to the films and this redox activity can be probed interactively by advanced electrochemical methods that allow the intrinsic redox reactivities to be compared, redox interactions to be identified, and biologically relevant redox activities to be examined. The transfer of chemical and biological information to a film is envisioned to provide broader access to the extensive capabilities offered by sensor technologies and signal processing methodologies. [ABSTRACT FROM AUTHOR]

Abstract: Recently, food safety application of microfluidic device has drawn increasing attentions, whereas the research in this field is still limited due to the complexity of food systems. Most of immunosensor technology has endeavored to improve the sensitivity of the assay. However, the major challenges in food allergen detection are to simplify detection by creating a device with both rapid and broaden detection range from threshold to the real-world concentration. In this work, an ELISA-based colorimetric detection of allergen in food systems was achieved using microfluidic device and regular optical microscope. Casein, the major allergen in milk, was selected as a model analyte. The results indicated that the device was superior to the traditional method and substantially simplified the allergen detection, by demonstrating rapid detection, wide detection range from threshold to real-world concentration. The total detection time was reduced substantially from 45min to 15min without diminishing the detection limit. The linear detection range of antigen was also increased by 5-log difference. Moreover, this study also investigated the mechanism and kinetic study of TMB in-channel oxidation, and established a protocol to determine microfluidic channel size and TMB incubation time for allergen detection in food systems. Therefore, this work not only demonstrated the capability and superiority of microfluidic device for food safety application, but also provided a general optimization method for rapid allergen detection in food systems. [Copyright &y& Elsevier]

The opportunistic pathogen Pseudomonas aeruginosa (P. aeruginosa) is associated gastrointestinal (GI) inflammation and illness; however, factors motivating commensal-to-pathogen transition are unclear. Excessive zinc intake from supplements is common in humans. Due to the fact that zinc exposure enhances P. aeruginosa colonization in vitro, we hypothesized zinc exposure broadly activates virulence mechanisms, leading to inflammation and illness. P. aeruginosa was treated with excess zinc and growth, expression and secretion of key virulence factors, and biofilm production were determined. Effects on invasion, barrier function, and cytotoxicity were evaluated in Caco-2 cells co-cultured with P. aeruginosa pre-treated with zinc. Effects on colonization, mucosal pathology, inflammation, and illness were evaluated in mice infected with P. aeruginosa pre-treated with zinc. We found the expression and secretion of key virulence factors involved in quorum sensing (QS), motility (type IV pili, flagella), biosurfactants (rhamnolipids), toxins (exotoxin A), zinc homeostasis (CzcR), and biofilm production, were all significantly increased. Zinc exposure significantly increased P. aeruginosa invasion, permeability and cytotoxicity in Caco-2 cells, and enhanced colonization, inflammation, mucosal damage, and illness in mice. Excess zinc exposure has broad effects on key virulence mechanisms promoting commensal-to-pathogen transition of P. aeruginosa and illness in mice, suggesting excess zinc intake may have adverse effects on GI health in humans. [ABSTRACT FROM AUTHOR]

Abstract: Five pH levels were experimented to study their effect on zein structural, rheological, and antioxidant properties. Structural changes, including secondary structures, surface charge, molecular weight, particle size distribution, and morphology were evaluated using a spectrum of instruments. Zein rheology, including the viscosity and viscoelastic property, was examined by a rheometer. The antioxidant efficacy was determined by measuring the scavenging activity of 1,1-diphenyl-2-picrylhydrazyl free radical and the reducing power of 1,10-phenanthroline-iron with a spectrophotometer. Results indicated that under proper acidic or basic conditions, zein structures, rheological behaviour, and antioxidant properties changed significantly. Decreased contents for α-helix, β-sheet, and β-turn were detected by the Fourier transform infrared spectroscopy for zein samples at acidic and basic conditions comparing to those in a near neutral condition, which were attributed to the deamidation of glutamine to glutamic acid/glutamate in zein. However, no obvious zein fragmentation or oligomerization was detected by the sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The mild deamidation without fragmentation led to a decreased viscosity and an improved antioxidant property of zein. Modified rheological behaviour and enhanced antioxidant properties resulting from a pH treatment may facilitate novel application development of zein in food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Abstract Battling meat adulteration is essential in preserving both public health and a fair market. This study depicts a method of reducing adulteration in meats, in which Electronic-nose (E-nose) and gas chromatography-mass spectrometer (GC-MS) were applied to identify adulterants in mutton. Duck meat was selected as a model adulterant due to its lower cost and similarity in flavor to mutton, as well as being frequently adulterated in China. Qualitative and quantitative analysis were conducted using linear regression, fisher linear discriminant analysis (FLDA), and multilayer perceptron neural networks analysis (MLPN) on E-nose signals. Several fingerprint volatile organic chemicals (VOC) were identified by GC-MS to validate the E-nose results. Multivariate partial least square regression (PLS) was carried out to study the relationships between GC-MS and E-nose. The results of GC-MS confirmed that E-nose can be used to identify duck adulteration in mutton, with a minimum detection ratio of 10%. This method proved that rapid detection of mutton adulterated duck meat using E-nose has a high accuracy, which has reduced detecting time and improved detection efficiency. Highlights • E-nose and GC-MS can be used to identify duck adulteration in mutton. • Detection of mutton adulterated duck meat using E-nose has a high accuracy. • E-nose detection was coupled with statistical analysis (MLPN, FLDA, PLS and LDA) for modeling. • E-nose can be used to identify duck adulteration in mutton, with a minimum detection ratio of 10%. [ABSTRACT FROM AUTHOR]

Abstract The increasing demand for safety and quality in food products has stimulated research on developing natural preservatives and their carrier systems as a novel preventive control strategy. In this study, metal-organic framework (MOF) was investigated, for the first time, as a carrier for volatile antimicrobial essential oils. Zinc metal-organic framework (Zn@MOF) was synthesized with zinc nitrate hexahydrate and 2-aminoterephthalic acid in N, N-dimethylformamide (DMF). Thymol was then loaded into the Zn@MOF at a loading rate of 3.96% as measured by thermogravimetric analysis (TGA). The crystal structure of porous MOF was confirmed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Antibacterial activity of thymol loaded Zn@MOF (T-Zn@MOF) with active thymol loading of 0.029 g/100 g was assessed against a three-strain cocktail of E. coli O157:H7 in a tryptic soy broth (TSB). E. coli O157:H7 growth in T-Zn@MOF exhibited growth inhibition without an exponential growth phase after 24 h of incubation, which could be attributed to the sustained release of thymol by incorporating it in the porous Zn@MOF through noncovalent interactions. This research demonstrates that Zn@MOF loaded with the essential oil thymol is an effective antimicrobial and may have potential indirect applications in food. Highlights • Metal-organic framework (MOF) was investigated for food safety application. • Antimicrobial essential oil, thymol, was selected as a model bioactive substance. • Zn@MOF was synthesized and characterized with a thymol loading at 3.96%. • Thymol loaded MOF showed promising antimicrobial activity against E. coli O157:H7. [ABSTRACT FROM AUTHOR]

Abstract Preservatives in processed meat raise significant concerns associated with bowel cancer and diabetes, and implicate various public health issues. This introduces the need for safer preservatives to uphold public health standards. However, developing safer alternatives to these preservatives poses a significant challenge to food industry. A potential solution to this issue is the use of loaded nanoparticles as preservative agents. This study investigated antimicrobial and antioxidant effects of sorbic acid-loaded chitosan/tripolyphosphate nanoparticles (SAN) in Chinese Sausage. SAN were prepared through ionic gelation, followed by natural air-drying for 20 days. After preparation, the antimicrobial and antioxidant activities of various treatment groups were analyzed intermittently during storage at room temperature. SAN-treated samples had significantly lower levels of surviving bacteria, molds, and yeasts than the blank control (p < 0.05) over the entire 72 days of storage. Additionally the SAN-treated samples also had lower levels of surviving bacteria than the chitosan/tripolyphosphate samples after 31–56 days of storage (p < 0.05). The thiobarbituric acid value and pH of the SAN-treated samples were also significantly lower than the blank control (p < 0.05). These results indicated that SAN could be a good intervention strategy to retard lipid oxidation and inhibit microbial growth in Chinese Sausage. Highlights • SAN were developed as alternatives to carcinogenic preservatives in processed meat products for the first time. • Chinese sausage was selected in evaluation of antimicrobial and antioxidant activities of SAN. • SAN exhibits superior activities to retard lipid oxidation and inhibit microbial growth in processed meat. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Small immune magnetic particles with diameter of ∼12 nm were fabricated. • The specific surface area of immune magnetic particles was 96.5 m2/g. • The distribution of antibody on the surface of magnetic particles was 25.8 μg/m2. • More than 3 × 108 of E. coli cells can be collected by 1 mg magnetic particles. • The QS signal was amplified ∼3 times than nature QS signal at total cell OD 0.08. Abstract Quorum sensing (QS) enables intercellular communication after bacterial cells sense the autoinducers have reached or exceeded a critical concentration. Selectively amplifying specific bacterial "quorum" activity at a lower cell density is still a challenge. Here, we propose a novel platform of immune magnetic nano-assembly to amplify specific bacterial QS signaling via improving the bioavailability of autoinducers-2 (AI-2, furanosyl borate) from sender (wide-type, WT cells) to receiver (reporter cells). Antibody coated magnetic nanoparticle (MNPAB) was fabricated with an average diameter of 12 nm and a specific surface area of 96.5 m2/g. The distribution efficiency of the antibody on the surface was 25.8 μg/m2 of magnetic nanoparticles. It was found that more than 3 × 108 of K12 serotype Escherichia coli (E. coli) reporter or WT cells were collected using 1 mg fabricated MNPAB at a saturated condition. The MNPAB not only captured E. coli WT cells but also brought them into proximity of E. coli (CT104, pCT6+pET-DsRed) reporter cells via magnetic attraction. The amplified QS signaling of the reporter cells by this immune magnetic nano-assembly was approximately 3 times higher than the nature QS signaling in cell suspension at optical density (OD) 0.08. This study foresees potential applications in amplifying specific biological QS signals based on a preprogrammed design. [ABSTRACT FROM AUTHOR]

Determining the minimal effective free chlorine (FC) concentration for preventing pathogen survival and cross-contamination during produce washing is critical for developing science- and risk-based food safety practices. The correlation between dynamic FC concentrations and bacterial survival was investigated during commercial washing of chopped Romaine lettuce, shredded Iceberg lettuce, and diced cabbage as pathogen inoculation study during commercial operation is not feasible. Wash water was sampled every 30 min and assayed for organic loading, FC, and total aerobic mesophilic bacteria after chlorine neutralization. Water turbidity, chemical oxygen demand, and total dissolved solids increased significantly over time, with more rapid increases in diced cabbage water. Combined chlorine increased consistently while FC fluctuated in response to rates of chlorine dosing, product loading, and water replenishment. Total bacterial survival showed a strong correlation with real-time FC concentration. Under approximately 10 mg/L, increasing FC significantly reduced the frequency and population of surviving bacteria detected. Increasing FC further resulted in the reduction of the aerobic plate count to below the detection limit (50 CFU/100 mL), except for a few sporadic positive samples with low cell counts. This study confirms that maintaining at least 10 mg/L FC in wash water strongly reduced the likelihood of bacterial survival and thus potential cross contamination of washed produce. [ABSTRACT FROM AUTHOR]

Chlorine, the most commonly used sanitizer for fresh produce washing, has constantly shown inferior sanitizing efficacy in the presence of organic load. Conventionally this is attributed indirectly to the rapid chlorine depletion by organics leading to fluctuating free chlorine (FC) contents. However, little is known on whether organic load affects the sanitization process directly at well-maintained FC levels. Hereby, a sustained chlorine decay approach was employed to study the inactivation of Escherichia coli O157:H7 under stabilized washing conditions. Chlorine solution was first incubated with organic load for up to 4 h, modeling the chlorination in produce washing lines. The FC level was then stabilized at five targeted values for sanitization study. Our study showed decreased sanitizing efficacy as the organic load increased. At 5 s residence time and pH 6.5, a minimum of 0.5 and 7.5 mg/L FC were needed to achieve a 5 log reduction at 0 and 900 mg/L chemical oxygen demand (COD), respectively. The decrease was more pronounced at lower FC, higher COD, higher pH, and shorter residence time values. The organics-associated interference with FC measurement and disruption of chlorine/bacteria interaction, together with the chlorine demand of concentrated inoculum per se, collectively resulted in inadequate sanitization. Finally, our results were compared with existing studies conducted under dynamic conditions in the context of different experimental settings. This study provided a feasible method for studying the bacteria/sanitizer interaction while ruling out the confounding effect from fluctuating FC levels, and it indicated the direct, negative impact of organic load. [ABSTRACT FROM AUTHOR]

In this research, winter jujubes were treated with X-ray doses of 0, 0.3, 0.5 kGy and stored at 0 °C. Then jujubes from early (day 0) and late (day 60) storage were transferred to 20 ± 1 °C and qualities were evaluated every 3 days to explore the preservation effect of X-ray. Results indicated that 0.3 kGy X-ray inhibited the jujube decay by preventing 8.20% of fungal and 29.12% of aerobic bacterial growth. The pectin decomposition was prevented (0.21% on day 60), softening was alleviated, and reddening was delayed for 5 days correspondingly. Microscopic observation validated the integrity of the treated jujube tissue. Furthermore, the highest inhibition rates of 0.3 kGy X-ray on the activities of polygalacturonase (PG), cellulase and β-glucosidase (β-Glu) were 47.32%, 74.71% and 68.00%, respectively. Research demonstrated X-ray's potential in winter jujube preservation, which can provide a solid theoretical reference for the development and industrial application. • 0.3 kGy X-ray extends the shelf-life of winter jujube stored at room temperature to 12 days. • 0.3 kGy X-ray inhibits 8.20% of fungal and 29.12% of aerobic bacterial growth. • 0.3 kGy X-ray decreases the activities of polygalacturonase (PG), cellulase and β-glucosidase (β-Glu) by 47.32%, 74.71% and 68.00%, respectively. • Winter jujube discoloration is positively correlated with softening decreases. [ABSTRACT FROM AUTHOR]

A novel nanocomposite of silver/titanium dioxide/chitosan adipate (Ag/TiO 2 /CS) was developed through photochemical reduction using a chitosan adipate template. Chitosan served as a reducing agent anchoring the metal ions through Ag–N coordination bonds and electrostatic attractions, thus stabilizing the Ag/TiO 2 /CS product observed by Fourier transform infrared spectroscopy and X-ray diffraction patterns. Scanning electron microscopy observations revealed that the nanocomposite particles (50–100 nm) were deposited onto the chitosan adipate layer. The product exhibited high ζ-potentials from 30.1 mV to 33.0 mV during 60 days of storage. In addition, the nanocomposite demonstrated higher antimicrobial activity than AgNO 3 or nano-Ag particles at similar concentrations, as evidenced by the inhibition zone, minimum inhibitory concentrations (MIC), and growth curve. The nanocomposite reduced the Escherichia coli population by 6 logs after 24 h of incubation, and had an MIC value of 0.38 μg Ag/mL. These results suggest that Ag/TiO 2 /CS has the potential to be used as an antibacterial protective coating for fruit storage. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes (L. monocytogenes) biofilm formation on food-contact surfaces is a significant food safety concern. However, research on the ability of contact surfaces to resist fouling by L. monocytogenes biofilm is limited. With the objective of assessing the combined effects of substrate topography and coating composition on L. monocytogenes biofilm formation, we used stainless steel 304 with three surface topographies (native finish, #4 commercial brushed finish, and native finish with microfabricated pillars developed by a new process), in each case either uncoated or coated with one of five FDA-approved food-contact substances (chromium nitride, titanium nitride, Dursan, Ni–P-polytetrafluoroethylene (Ni–P-PTFE), and Lectrofluor 641). Results indicate that surface topography and composition significantly affected fouling resistance. Significant enhancement of resistance to L. monocytogenes fouling was observed on native finish coated by Ni–P-PTFE, which reduced L. monocytogenes by 1.5 Log CFU/cm2. Coating the brushed finish with Ni–P-PTFE, Lectrofluor 641, or Dursan reduced L. monocytogenes fouling by 0.5, 0.4, and 0.9 Log CFU/cm2, respectively. The greatest reductions in L. monocytogenes biofilm formation were obtained with Dursan coated on the native finish (3.4 Log CFU/cm2) and on the micropillar-modified native finish (2.8 Log CFU/cm2). The combined variation of substrate topography modification and coating composition provides a new approach to enhance fouling resistance of stainless steel against L. monocytogenes biofilm for improved sanitary design of food processing equipment. • Nonfouling enhancement of stainless steel against Listeria monocytogenes biofilm. • Combination of topography modification and food contact substances (FCS) coating. • Dursan coating demonstrates the strikingly good fouling-resistant effect. • The new strategy can be applied for improved food processing equipment design. [ABSTRACT FROM AUTHOR]

We have developed an inexpensive, standardized paper chromogenic array (PCA) integrated with a machine learning approach to accurately identify single pathogens (Listeria monocytogenes , Salmonella Enteritidis, or Escherichia coli O157:H7) or multiple pathogens (either in multiple monocultures, or in a single cocktail culture), in the presence of background microflora on food. Cantaloupe, a commodity with significant volatile organic compound (VOC) emission and large diverse populations of background microflora, was used as the model food. The PCA was fabricated from a paper microarray via photolithography and paper microfluidics, into which 22 chromogenic dye spots were infused and to which three red/green/blue color-standard dots were taped. When exposed to VOCs emitted by pathogens of interest, dye spots exhibited distinguishable color changes and pattern shifts, which were automatically segmented and digitized into a ΔR/ΔG/ΔB database. We developed an advanced deep feedforward neural network with a learning rate scheduler, L 2 regularization, and shortcut connections. After training on the ΔR/ΔG/ΔB database, the network demonstrated excellent performance in identifying pathogens in single monocultures, multiple monocultures, and in cocktail culture, and in distinguishing them from the background signal on cantaloupe, providing accuracy of up to 93% and 91% under ambient and refrigerated conditions, respectively. With its combination of speed, reliability, portability, and low cost, this nondestructive approach holds great potential to significantly advance culture-free pathogen detection and identification on food, and is readily extendable to other food commodities with complex microflora. • A paper chromogenic array (PCA) - machine learning approach was developed to accurately identify multiple pathogens in background microflora. • PCAs, fabricated via photolithography, react with volatile organic compounds to exhibit distinguishable color pattern shifts. • An advanced neural network demonstrated excellent performance with a learning rate schedule, L2 regularization, and shortcut connections. • This nondestructive approach holds great potential to significantly advance culture-free pathogen detection and identification on food. [ABSTRACT FROM AUTHOR]

Retail display of highly perishable foods behind glass doors ensures uniform product temperatures below the FDA Food Code threshold of 5 °C, resulting in better-preserved foods while reducing energy costs. However, only a handful of studies have evaluated the effect of repeated door openings on product temperatures and energy consumption with contrasting reports. In this paper, we evaluated the effects of two frequencies (doors opened every 5 or 15 min) and four durations (doors held ajar for 5, 15, 30 or 60 s) on product simulator temperatures in a display case installed in our research supermarket. At ambient conditions (19.6–20.9 °C, 63% RH), with a case thermostat setting of 0.6 °C and a daily 30-min defrost cycle, the only statistically significant fluctuation in product simulator temperatures was found for the most aggressive opening schedule where the door was opened every 5 min for 60 s at each opening. Pairwise comparisons demonstrated that this treatment resulted in product simulator temperatures (up to 6.6 °C during defrost cycle) that were significantly higher (p < 0.001) or somewhat significantly higher (p < 0.03) compared to product exposed to all other combinations. Product exposed to all other treatment combination resulted in temperatures that either never exceeded 5 °C or briefly exceeded it only during the single 30-min defrost cycle. As a result, we selected an average opening sequence (every 10 min for 12 s) to perform an energy consumption assessment of the case. Energy consumption was determined to be 66% lower than that compared to an open-retail display case (same model, mark, size, operating schedule and thermostat setting). Even with the most extreme schedule where three of the six doors remained open continuously, there was still a measured 45% reduction in energy consumption as compared to that of the open-retail display case. • Enclosed refrigerated display cases support compliance with US Food Code. • Typical door opening regimes do not impact product temperature uniformity in display cases. • Typical door opening regimes still provide significant energy savings compared to an open display case. [ABSTRACT FROM AUTHOR]

Huanglongbing (HLB) is a highly destructive disease that inflicts significant economic losses on the citrus industry worldwide but with no cure available. However, microbiomes formulated by citrus plants may serve as disease antagonists, increasing the level of HLB tolerance. This study established an integrated analysis of untargeted metabolomics and microbiomics data for different citrus cultivars, providing critical insights into the interactions between plant metabolism and plant-associated bacteria in the development of HLB. Machine learning models were applied to screen important metabolites and bacteria in multiple citrus materials, and the selected metabolites were then analyzed to identify essential pathways enriched in the plant and to correlate with the selected bacteria. Results demonstrated that the regulation of plant pathways, especially ABC transporters and ubiquinone and other terpene-ubiquinone biosynthesis pathways, could affect the microbial community structure, indicating potential solutions for controlling HLB by modulating bacteria in citrus plants or breeding tolerant citrus cultivars.

A magnetic nanocomposite film with the capability of reversibly collecting functionalized magnetic particles was fabricated by simultaneously imposing two orthogonal stimuli (electrical and magnetic). We demonstrate that cathodic codeposition of chitosan and Fe3O4 nanoparticles while simultaneously applying a magnetic field during codeposition can (i) organize structure, (ii) confer magnetic properties, and (iii) yield magnetic films that can perform reversible collection/assembly functions. The magnetic field triggered the self-assembly of Fe3O4 nanoparticles into hierarchical "chains" and "fibers" in the chitosan film. For controlled magnetic properties, the Fe3O4-chitosan film was electrodeposited in the presence of various strength magnetic fields and different deposition times. The magnetic properties of the resulting films should enable broad applications in complex devices. As a proof of concept, we demonstrate the reversible capture and release of green fluorescent protein (EGFP)-conjugated magnetic microparticles by the magnetic chitosan film. Moreover, antibody-functionalized magnetic microparticles were applied to capture cells from a sample, and these cells were collected, analyzed, and released by the magnetic chitosan film, paving the way for applications such as reusable biosensor interfaces (e.g., for pathogen detection). To our knowledge, this is the first report to apply a magnetic field during the electrodeposition of a hydrogel to generate magnetic soft matter. Importantly, the simple, rapid, and reagentless fabrication methodologies demonstrated here are valuable features for creating a magnetic device interface.

We have developed a two-step replica molding method for rapid fabrication of biomimetically patterned plant surfaces (BPS) using polydimethylsiloxane (PDMS-BPS) and agarose (AGAR-BPS). Beyond providing multiple identical specimens that faithfully reproduce leaf surface microstructure, this approach also offers unique chemical, physical, and biological features. PDMS-BPS provide good structural durability for SEM examination, have surface wettability comparable to plant surfaces for coating development, and allow for real-time monitoring of biosynthesis through incorporation into microfluidic devices. AGAR-BPS are compatible with bacterial growth, recovery, and quantification, and enable investigation of the effects of surface topography on spatially varying survival and inactivation of Escherichia coli cells during biocide treatment. Further development and application of these biomimetically patterned surfaces to study (and possibly modify) other aspects of plant-bacteria interactions can provide insight into controlling pathogen contamination in a wide range of applications.

Cationic β-lactoglobulin (CBLG) was developed as a bioavailability enhancer for poorly absorbed bioactives. At most 11 anionic amino acid residues of β-lactoglobulin (BLG) were substituted by ethylenediamine (EDA), resulting in a highly positive surface charge (zeta potential up to 39 mV at pH 7.0) and significantly increased surface hydrophobicity. These changes conferred CBLG with desirable water solubility and improved mucoadhesion by at most 252%, according to quartz crystal microbalance (QCM) study. Furthermore, CBLG inherited the unique resistance to gastric digestion from BLG, while the digestion under simulated intestinal condition was significantly improved. The latter was possibly due to the formation of aspartic acid-EDA conjugates, together with the randomization of protein conformation related with decreased percentage of β-sheet. Compared to BLG, CBLG formed smaller (75-94 nm), more uniform nanoparticles by the acetone-desolvation method. These merits made CBLG a useful material that provides desirable solubility, controlled release, and enhanced absorption to nutraceuticals or drugs.

In this study, soy protein isolate (SPI) was conjugated with folic acid (FA) to prepare nanoparticles for target-specific drug delivery. Successful conjugation was evidenced by UV spectrophotometry and primary amino group analysis. An increase in count rate by at least 142% was observed in FA-SPI nanoparticles compared to the nonconjugated ones, whereas the particle size was decreased upon FA conjugation. This was probably attributed to the substitution of positively charged lysine residues by the FA backbone. The ζ-potential ranged from -36 to -42 mV depending on the conjugation degree, indicating desirable dispersion stability. Curcumin as a model drug was encapsulated successfully into FA-SPI nanoparticles, evidenced by X-ray diffraction study. The highest encapsulation and loading efficiencies were around 92.7% and 5.4%, respectively, which were significantly higher (P < 0.05) than those with nonconjugated SPI nanoparticles. In addition, a faster and more complete release of curcumin was observed for FA-SPI nanoparticles in PBS/Tween 20 buffer. Cell culture study showed that conjugation of FA resulted in an increase in cellular uptake by at most 93% in Caco-2 cells. These results suggested that FA-SPI is a potential wall material for encapsulation and enhanced delivery of anticancer drugs.