Selective Elucidation of Living Microbial Communities in Fermented Grains of Chinese Baijiu: Development of a Technique Integrating Propidium Monoazide Probe Pretreatment and Amplicon Sequencing.

The fermentation process of Chinese Baijiu's fermented grains involves the intricate succession and metabolism of microbial communities, collectively shaping the Baijiu's quality. Understanding the composition and succession of these living microbial communities within fermented grains is crucial for comprehending fermentation and flavor formation mechanisms. However, conducting high-throughput analysis of living microbial communities within the complex microbial system of fermented grains poses significant challenges. Thus, this study addressed this challenge by devising a high-throughput analysis framework using light-flavor Baijiu as a model. This framework combined propidium monoazide (PMA) pretreatment technology with amplicon sequencing techniques. Optimal PMA treatment parameters, including a concentration of 50 µM and incubation in darkness for 5 min followed by an exposure incubation period of 5 min, were identified. Utilizing this protocol, viable microorganism biomass ranging from 8.71 × 106 to 1.47 × 108 copies/µL was successfully detected in fermented grain samples. Subsequent amplicon sequencing analysis revealed distinct microbial community structures between untreated and PMA-treated groups, with notable differences in relative abundance compositions, particularly in dominant species such as Lactobacillus, Bacillus, Pediococcus, Saccharomycopsis, Issatchenkia and Pichia, as identified by LEfSe analysis. The results of this study confirmed the efficacy of PMA-amplicon sequencing technology for analyzing living microbial communities in fermented grains and furnished a methodological framework for investigating living microbial communities in diverse traditional fermented foods. This technical framework holds considerable significance for advancing our understanding of the fermentation mechanisms intrinsic to traditional fermented foods.

Determination of insecticide residues in beverages based on MIL-100(Fe) dispersive solid-phase microextraction in combination with dispersive liquid-liquid microextraction followed by HPLC-MS/MS.

A novel dispersive solid-phase microextraction method based on a metal-organic framework (MIL-100(Fe)) combined with a dispersive liquid-liquid microextraction technique was proposed for the extraction and enrichment of four insecticides in beverages. The qualitative and quantitative analysis of these insecticides was conducted using HPLC-MS/MS. To optimize the extraction process, several parameters were investigated, and the main variables were optimized using CCD-based RSM. The developed method displayed a wide linear range of 1.000-1000 ng/L and R2 values >0.993 for all four calibration curves. The method demonstrated high sensitivity, with LODs and LOQs of 0.3-0.6 ng/L and 0.8-1.0 ng/L, respectively. In addition, the greenness of the proposed method was assessed using the Complex GAPI tool, and the results showed that the proposed method exhibits benefits, such as minimal usage of organic solvents and negligible matrix influence, making it a suitable method for the detection of insecticide residues in beverages.

Separation and Detection of Catechins and Epicatechins in Shanxi Aged Vinegar Using Solid-Phase Extraction and Hydrophobic Deep Eutectic Solvents Combined with HPLC.

This research presents a new, eco-friendly, and swift method combining solid-phase extraction and hydrophobic deep eutectic solvents (DES) with high-performance liquid chromatography (SPE-DES-HPLC) for extracting and quantifying catechin and epicatechin in Shanxi aged vinegar (SAV). The parameters, such as the elution solvent type, the XAD-2 macroporous resin dosage, the DES ratio, the DES volume, the adsorption time, and the desorption time, were optimized via a one-way experiment. A central composite design using the Box-Behnken methodology was employed to investigate the effects of various factors, including 17 experimental runs and the construction of three-dimensional response surface plots to identify the optimal conditions. The results show that the optimal conditions were an HDES (tetraethylammonium chloride and octanoic acid) ratio of 1:3, an XAD-2 macroporous resin dosage of 188 mg, and an adsorption time of 11 min. Under these optimal conditions, the coefficients of determination of the method were greater than or equal to 0.9917, the precision was less than 5%, and the recoveries ranged from 98.8% to 118.8%. The environmentally friendly nature of the analytical process and sample preparation was assessed via the Analytical Eco-Scale and AGREE, demonstrating that this method is a practical and eco-friendly alternative to conventional determination techniques. In summary, this innovative approach offers a solid foundation for the assessment of flavanol compounds present in SAV samples.

The Separation, Purification, Structure Identification, and Antioxidant Activity of Elaeagnus umbellata Polysaccharides.

In order to investigate the antioxidant activity of Elaeagnus umbellata polysaccharides, the physicochemical characteristics of purified Elaeagnus umbellata polysaccharides (EUP, consisting of two fractions, EUP1 and EUP2) were investigated using UV spectrophotometry, high-performance liquid chromatography (HPLC), high-performance gel permeation chromatography (HPGPC), and Fourier transform infrared spectroscopy (FT-IR). This revealed that EUP1 and EUP2 were acidic polysaccharides with an average molecular weight (MW) of 63 and 38 kDa, respectively. EUP1 mainly consisted of L-rhamnose and D-galactose in a molar ratio of 2.05:1, and EUP2 consisted of D-mannose, L-rhamnose, D-galactose, and D-arabinose in a molar ratio of 2.06:1:2.78:1. Furthermore, EUP exhibited considerable antioxidant potential for scavenging hydroxyl, superoxide anion, DPPH, and ABTS radicals. Therefore, EUP can be developed as a potential antioxidant for the functional food or pharmaceutical field.

Correlation Analysis of Microbial Community Changes and Physicochemical Characteristics in Aged Vinegar Brewing.

This study aimed to explore key physicochemical characteristics and evolutionary patterns of microbial community structure during the fermentation of aged vinegar. The correlation between microorganisms and physicochemical characteristics during fermentation was examined. The results revealed significant differences in genera at different stages of fermentation. The dominant bacteria in R1 were Bacillus, Lactobacillus, Aspergillus, and Issatchenkia. During the R2 fermentation stage, Lactobacillus, Acetobacter, and Saccharomyces exhibited an upward trend and finally became the dominant bacteria. Aspergillus was the main bacterial genus at the end of overall fermentation. The correlation analysis showed that the bacterial genera significantly positively and negatively correlated with reducing sugars and amino acid nitrogen were the same in Cuqu. Similarly, the bacterial genera significantly positively and negatively correlated with pH and saccharification power were the same. pH, reducing sugar, and saccharification ability were mainly positively correlated with bacterial genera during fermentation. Further, studies found that the overall correlation between fungal communities and physicochemical characteristics was weaker than the correlation with bacteria during fermentation.

Determination of Flavonoid Compounds in Shanxi Aged Vinegars Based on Hydrophobic Deep Eutectic Solvent VALLME-HPLC Method: Assessment of the Environmental Impact of the Developed Method.

This research presents a novel, eco-friendly, vortex-assisted liquid-liquid microextraction (VALLME) approach, integrating hydrophobic deep eutectic solvents (DESs) with HPLC for the identification and quantification of nine specific flavonoids in Shanxi aged vinegar (SAV). The parameters of DES-VALLME, including the ratio of trioctylmethylammonium chloride to 1,4-butanediol (1:6), DES volume (150 µL), vortex duration (5 min), the concentration of NaCl (0.40 g), and centrifugation time (10 min), were optimized to achieve the maximum extraction efficiency of target substances. Under these optimal conditions, quantitative analyses performed via HPLC demonstrated a broad linear range of 0.20-50.00 µg/mL and correlation coefficients (r2) greater than 0.9944 for all nine calibration curves. The limits of detection (LOD) and limits of quantitation (LOQ) were 0.09-0.18 µg/mL and 0.30-0.60 µg/mL, respectively, ensuring high sensitivity. The relative standard deviations for intra-day and inter-day variability were within the acceptable range, 2.34-3.77% and 3.04-4.96%, respectively, demonstrating the method's reliability. The recovery rates ranged from 85.97% to 108.11%, underscoring the method's precision. This technique exhibited a significant enrichment effect (enrichment factor: 43 to 296) on SAV flavonoids. Notably, the eco-friendliness of this procedure was evaluated using the Analytical Eco-Scale, Green Analytical Procedure Index, and Analytical Greenness Metric. The results suggested that this technique is a viable green alternative to traditional flavonoid determination methods in SAV. In summary, this novel method provides a theoretical basis for assessing flavonoid content in SAV samples and tracing SAV products. This contribution has significant implications for enhancing analytical techniques in food chemistry and environmental science and the sustainable development of the food industry.

Diversity of Fusarium community assembly shapes mycotoxin accumulation of diseased wheat heads.

Fusarium head blight (FHB) is a major disease worldwide on cultivated cereals, caused by several Fusarium species. FHB can cause not only yield reduction but also accumulation of mycotoxins in the grain contaminating the food supply. Much of the earlier research has focused on Fusarium pathogenesis, conditions required for disease development and toxin accumulation, and FHB management. However, the Fusarium community composition within the micro-habitat of a single diseased wheat head in the field has had limited investigation. Similarly, the relationship between the Fusarium community structure and mycotoxin accumulation within diseased heads remains unclear. In the present study, we investigated the Fusarium community in diseased heads sampled from different geographical sites in China. Several sites in Shandong province formed a transitional region which contained highly variable profiles of Fusarium OTUs, where a single diseased head could contain more than 10 Fusarium OTUs. Mycotoxin accumulation was independent of geographical properties, however, deoxynivalenol, 15-acetyldeoxynivalenol and zearalenone concentrations showed a significant negative correlation with Fusarium diversity on diseased heads while a significant positive correlation between nivalenol concentration and Fusarium diversity was observed. Taken together, the Fusarium OTU diversity within diseased heads in the field significantly influences mycotoxin accumulation, providing an important point to consider in FHB disease management and mycotoxin research.

Structure, physicochemical properties, antioxidant, and hypoglycemic activities of water-soluble polysaccharides from millet bran.

This study aimed to investigate the composition, structure, in vitro antioxidant, and hypoglycemic activities of a novel water-soluble MBP-1, an extract from millet bran, isolated by DEAE-52 cellulose and purified by Sephadex G-100. The results showed that MBP-1 was mainly composed of xylose, mannose, galactose, rhamnose, and arabinose with a molar ratio of 0.72:0.59:76.26:1.04:0.83 and a molecular weight of 6.6×104  Da, and its purity was 98%, and the yield was 3.76%. MBP-1 has an irregular granular structure by atomic force microscopy and scanning electron microscopy, and the anomeric carbon in MBP-1 molecule has α-configuration and ß-configuration by NMR and FTIR. The in vitro scavenging abilities of MBP-1 for·OH, DPPH, O2·- , and ABTS+ were 73.5%, 80%, 69.8%, and 75.2%, respectively, and the chelating activity for Fe2+ was 50%, and the inhibition rates of α-glucosidase and α-amylase were 78.5% and 74.6%, respectively, which indicated that MBP-1 possessed strong antioxidant and hypoglycemic activities. The results indicated that MBP-1 have certain application prospects in food-related fields.

Antidiabetic Effect of Millet Bran Polysaccharides Partially Mediated via Changes in Gut Microbiome.

Diabetes is a type of metabolic disease associated with changes in the intestinal flora. In this study, the regulatory effect of millet bran on intestinal microbiota in a model of type 2 diabetes (T2DM) was investigated in an effort to develop new approaches to prevent and treat diabetes and its complications in patients. The effect of purified millet bran polysaccharide (MBP) with three different intragastric doses (400 mg/kg, 200 mg/kg, and 100 mg/kg) combined with a high-fat diet was determined in a streptozotocin (STZ)-induced model of T2DM. By analyzing the changes in indicators, weight, fasting blood sugar, and other bio-physiological parameters, the changes in gut microbiota were analyzed via high-throughput sequencing to establish the effect of MBP on the intestinal flora. The results showed that MBP alleviated symptoms of high-fat diet-induced T2DM. A high dosage of MBP enhanced the hypoglycemic effects compared with low and medium dosages. During gavage, the fasting blood glucose (FBG) levels of rats in the MBP group were significantly reduced (p < 0.05). The glucose tolerance of rats in the MBP group was significantly improved (p < 0.05). In diabetic mice, MBP significantly increased the activities of CAT, SOD, and GSH-Px. The inflammatory symptoms of liver cells and islet cells in the MBP group were alleviated, and the anti-inflammatory effect was partially correlated with the dose of MBP. After 4 weeks of treatment with MBP, the indices of blood lipid in the MBP group were significantly improved compared with those of the DM group (p < 0.05). Treatment with MBP (400 mg/kg) increases the levels of beneficial bacteria and decreases harmful bacteria in the intestinal tract of rats, thus altering the intestinal microbial community and antidiabetic effect on mice with T2DM by modulating gut microbiota. The findings suggest that MBP is a potential pharmaceutical supplement for preventing and treating diabetes.

Probiotic Properties Including the Antioxidant and Hypoglycemic Ability of Lactic Acid Bacteria from Fermented Grains of Chinese Baijiu.

In this study, lactic acid bacteria (LAB) strains were isolated from fermented grains of traditional Chinese Baijiu, and their probiotic properties were characterized. Eleven out of 29 LAB strains showed good tolerance to the gastrointestinal tract and bile salts. The surface characteristics (auto-aggregation, co-aggregation, hydrophobicity), safety (hemolytic and antibiotic sensitivity), antibacterial activity against three foodborne pathogens, and antioxidant and hypoglycemic properties of the 11 LAB strains were investigated. Principal component analysis (PCA) was used to comprehensively evaluate LAB strains and their probiotic properties. It was found that Weissella cibaria (OP288150), Pediococcus acidilactici (OP288151), Pediococcus pentosaceus (OP288154), Pediococcus pentosaceus (OP288156) and Levilactobacillus brevis (OP288158) showed high probiotic properties, with potential for commercial development. The results also demonstrated that fermented grains of Chinese Baijiu can be used as a source of high-quality probiotics.

Functional Characteristics of Lactic Acid Bacteria In Vitro Isolated from Spontaneously Fermented Sour Porridge with Broomcorn Millet in Northwestern Shanxi Province of China.

Eighteen strains of lactic acid bacteria were isolated from spontaneously fermented sour porridge with broomcorn millet in Northwestern Shanxi Province of China, and their probiotic characteristics were investigated in vitro. Survival rates under gastrointestinal conditions, cholesterol reduction, antibacterial capabilities, antioxidant activities, and safety assessments were examined. Results showed that five strains were selected as probiotics and identified as Levilactobacillusbrevis. Strain L10 exhibited excellent probiotic characteristics, with an 86% survival rate under pH 2.0 for 2 h, 80% survival rate in 0.3% bile salt for 6 h, the highest survival rate (78%) in simulated gastrointestinal juice for 3 h, the highest hydrophobicity (42% to xylene and 39% to hexadecane), the highest aggregation (39% auto-aggregation and 10.4-18.13% co-aggregation), relative higher cholesterol reduction rate (80%), the highest antibacterial activities, the highest antioxidant activity, sensitive to most antibiotics tested, without hemolytic and hydrolyze gelatinase activity and could not produce biogenic amine. Therefore, strain L10 could be applied to functional foods.

The antibacterial mechanism of perilla rosmarinic acid.

Rosmarinic acid (RosA) is a phenolic acid compound extracted from perilla. In this experiment, the Oxford cup method was used to verify the antibacterial activity of PerillaRosA against Escherichia coli, Staphylococcus aureus, Salmonella, and Bacillus subtilis. By polyacrylamide gel electrophoresis, the effect of RosA on bacterial nucleic acid and bacterial Na+ /K+ -ATP-ase activity, and scanning electron microscope to exploration of its antibacterial mechanism preliminarily. The results showed that RosA had antibacterial properties against all four bacteria. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of E. coli were 0.8 and 0.9 mg/ml, respectively. The MIC and MBC of Salmonella were 0.9 and 1.0 mg/ml, respectively. The MIC and MBC of S. aureus and B. subtilis were both 1.0 and 1.1 mg/ml. RosA has the bacteriostasis function, which can destroy bacterial cells and cell proteins and inhibit the activity of Na+ /K+ -ATP-ase in cells.

Surface molecularly imprinted magnetic MOFs: A novel platform coupled with magneto electrode for high throughput electrochemical sensing analysis of oxytetracycline in foods.

In order to solve inherent problems of traditional molecularly imprinted electrochemical sensors (MIECS), a novel platform of surface molecularly imprinted magnetic metal-organic frameworks (mMOFs@MIPs) was coupled with magneto electrode to establish magnetic MIECS for the recognition of oxytetracycline (OTC). mMOFs@MIPs were synthesized using layer-by-layer modification method for the recognition of OTC. With the help of magneto electrodes, mMOFs@MIPs can be magnetically modified on the electrode surface, forming the electrochemical sensing interface. The imprinted cavities of mMOFs@MIPs can act as the electron channel of the probe to realize label-free detection of OTC. A linear response was obtained within the OTC concentration range of 1.0 × 10-9 g mL-1-1.0 × 10-4 g mL-1. The applicability of the sensor was estimated using the spiking and recovery method in milk samples with the recoveries ranging from 89.0% to 103.1%. It has potential applications in food safety analysis with high throughput detection capability, high specificity and good stability.

Genetic diversity of Venturia inaequalis isolates (Apple scab) in China and U.K. determined by SSR markers.

Apple scab caused by Venturia inaequalis is a serious disease of cultivated apple worldwide. In this study, we collected 132 V. inaequalis isolates from Shaanxi, Gansu, Xinjiang, and the U.K. and analyzed their genetic diversity by using 13 microsatellite markers. Cluster analysis based on population structure and genetic distances suggested high similarity among the four regions. Population differentiation values ranged from 0.044 to 0.155, indicating there is a high level of kinship among the four regions. All isolates could be divided into 5 lineages with a 0.76 similarity coefficient. Among the four regions, Shaanxi had only one lineage, Group II; Gansu had four lineages, Group I, Group II, Group IV, and Group V; Xinjiang had all five lineages, Group I, Group II, Group III, Group IV, and Group V; and the U.K. had three lineages, Group I, Group II and Group IV. High molecular variance was detected for populations in the four regions, with 91% of the variance occurring within the populations and 9% among the populations. Structure analysis there are three common ancestors of these four regions. The results of the present study shed light on the genetic diversity of V. inaequalis in Shaanxi, Gansu and Xinjiang, which will lead to the development of more effective management strategies and new resistant apple cultivars through molecular marker-assisted selection.

The Whole Genome Sequence of Fusarium redolens Strain YP04, a Pathogen that Causes Root Rot of American Ginseng.

Fusarium redolens was previously reported as a plant pathogen or an endophyte that is closely related to F. oxysporum, a notoriously significant soilborne phytopathogen. Subsequent studies demonstrated the unique nature of F. redolens, which was considered a distinct species that causes multiple symptoms on multiple hosts. It was recently identified as a pathogen that causes root rot of American ginseng. Currently, few high-quality F. redolens genome sequences exist in the public database. Here, we report the whole-genome sequence of F. redolens strain YP04, based on a hybrid assembly of long- and short-read sequencing with PacBio and Illumina platforms, respectively. The assembly consists of 40 configs with a total length of 52.8 Mb nuclear genomic DNA and 49.6 kb complete mitochondrial genomic DNA, and encodes a total of 18,985 genes, including 18,517 protein-coding genes and 469 RNA genes which were functionally annotated. In total, 4,606 proteins were identified in the pathogen-host interactions database, suggesting that they were likely involved in pathogenicity and host-pathogen interactions, while 41 secondary metabolite synthesis clusters were predicted and annotated. This is the first high-quality whole genome of F. redolens, providing an important community resource for genome evolution, host-pathogen interaction, and secondary metabolite biosynthesis studies.

Studies on Adsorption Kinetics and Thermodynamics of Macroporous Resin for Rosmarinic Acid.

This experiment treated perilla seeds with different concentrations of NaCl solution to enrich and purify their rosmarinic acid (RosA). The results showed that low concentrations of salt (0-20 mmol/L) promoted seed germination, while high concentrations (> 20 mmol/L) inhibited germination. When the salt concentration was 20 mmol/L, the germination rate was the highest. The content of RosA in germinated perilla seeds was 3.5 mg/g, which was 3.5 times as much as that in the seeds without germination. The RosA was purified using NK-109 macroporous resin and its adsorption kinetics, isotherms and thermodynamics were determined. The adsorption kinetics showed that the adsorption behavior of RosA in NK-109 resin conformed to the pseudo-second-order kinetic model. The model for RosA in the NK-109 resin exhibited Langmuir adsorption based on a spontaneous exothermic process according to its adsorption thermodynamics, which included both physical and chemical adsorption. The optimized process conditions were as follows: the loading concentration of 0.04 mg/mL, loading volume of 40 mL, 70% methanol as the eluent with the volume of 60 mL, and the purity of RosA was 42.1%.

Development of a molecularly imprinted photoelectrochemical sensing platform based on NH2-MIL-125(Ti)-TiO2 composite for the sensitive and selective determination of oxtetracycline.

In this work, a molecularly imprinted photoelectrochemical (MIP-PEC) sensor based on a novel PEC composite of metal-organic frameworks (MOFs) and TiO2 (NH2-MIL-125(Ti)-TiO2) was established for the ultrasensitive and selective detection of oxytetracycline (OTC). This is the first attempt of applying MOFs in the construction of MIP-PEC sensor. The NH2-MIL-125(Ti)-TiO2 was synthesized by a simple one-step solvothermal method and modified onto the surface of indium tin oxide (ITO) electrode as the photosensitive layer. Subsequently, molecularly imprinted polymer (MIP) was modified as recognition element by electropolymerization. The NH2-MIL-125(Ti)-TiO2 showed an enhanced photocurrent response due to stronger light absorption capacity and matched energy band. Furthermore, MIP greatly improved the selectivity and sensitivity of the constructed PEC sensor. The photocurrent response of the MIP-PEC sensor was reduced after OTC recognition because the specific binding of OTC to the imprinted cavities blocked the electron transfer of the electrode. Under optimal experimental conditions, the MIP-PEC sensor exhibited a wide detection range from 0.1 nM to 10 µM with a low limit of detection (LOD) of 60 pM, as well as certain reproducibility, stability and good applicability in real samples. The proposed sensor provides ideas for the application of MOFs in the construction of PEC sensors and will offer an alternative method for the detection of other pollutants in the field of food safety.

American Ginseng Root Rot Caused by Fusarium redolens in China.

American ginseng (Panax quinquefolium L.) originating from North America is one of important herbal medicine and economic crops . With the increasing market demand, China has become the third producer and the largest consumer country of American ginseng. However, continuous cropping obstacle has become the most serious problem for the production of American ginseng, and the continuous cropping of soils usually lead to accumulations of root fungal pathogens and increasing plant disease occurrence (1), root rot caused by the notorious soil-borne pathogenic fungi, Fusarium spp., results in a significant reduction of yield and quality of American ginseng. Investigation of American ginseng root rot was carried out in Liuba county, Shaanxi province, China from 2017 to 2019. About 20% of over 3-year-old American ginseng showed varied root rot symptoms in newly reclaimed fields, and more than 70% in continuous American ginseng planting fields. Among these root rot diseases, we found one kind of disease which shows symptoms of red leaves in initial stage and yellow or yellow brown lesions at the reed heads or taproots. The lesions mainly appear on the root surface; however, the vascular tissue has no discoloration. The aboveground parts become wilted and died, and the whole root appears dark brown rots. Fifteen Fusarium spp. isolates were obtained by cutting diseased rot roots into 5 × 5 mm2 pieces, disinfecting in 70% ethanol for 1 min, rinsing 2 ~ 3 times in sterile water for 1 min and isolating on PDA medium including 50 µg/mL streptomycin sulfate. All the isolates have identical morphological characteristics. The colony was white with curved and uplifted aerial hyphae in central region. The colony diameter was 48 ~51 mm after 6 days at room temperature. Microconidia were oval to cylindrical shape with 0 to 1 septa, ranged from 6.24 to10.09 µm long; the macroconidia were fusiform to conical with a hooked apical cell and a foot-shaped basal cell, usually 3 to 5 septa, ranged from 31.45 to 42.52 µm long. The chlamydospores were not found under our culture condition. Preliminary data analysis showed that the morphological characteristics of these isolates were consistent with the descriptions of Fusarium redolens (2). To clarify the fungus in the taxonomy , the rDNA internal transcribed spacer (ITS), the translation elongation factor 1 alpha (TEF1-α) and the RNA polymerase II subunit 1 (RPB1) fragments of two randomly selected isolates were amplified and sequenced. The sequences of the corresponding fragments of the two isolates were identical. The blast results in the GenBank and FUSARIUM-ID databases show the isolates belong to F. redolens (3). Previous study indicated F. redolens has an indistinguishable relative, F. hostae (4). Although the ITS sequence (MW331695) cannot provide enough information to distinguish them, the phylogenetic tree combined the sequence of TEF1-α (tempID: 2407237 ) and RPB1 (tempID: 2407229) clearly showed that the isolates are F. redolens. (Fig) The pathogenicity of a representative isolate, YP04, was tested on ginseng taproot by in vivo inoculation experiments with three replications. The taproot surface of 2-year-old healthy ginseng was washed and disinfested with 75% alcohol for 1 min and rinsed with sterile water, and dried. The surface of taproot was injured with sterilized steel needles and immersed in 1 × 106 /ml spore suspension (sterile water for control plants) for 30 min. The treatment and control plants were transplanted in 20 cm diameter flowerpots filled with sterilized humus and cultured in a greenhouse at 18-23°C. Six days after transplanting, the leaves began to turn red. The cortex of ginseng taproot showed yellow brown lesions and the vascular tissue turn to light yellow. Fifteen days after transplanting, the aboveground parts of treatment plants began to wilting and the taproots showed serious rots. no taproot rot was observed in the controls. The pathogen was re-isolated from the diseased taproots successfully. To our knowledge, this is the first report of F. redolens causing root rot of American ginseng in China.

Changes in the Microbiome in the Soil of an American Ginseng Continuous Plantation.

American ginseng is an important herbal medicinal crop in China. In recent years, there has been an increasing market demand for ginseng, but the production area has been shrinking due to problems associated with continuous monocropping. We analyzed the microbiome in bulk soils to assess whether and, if so, what changes in the bulk soil microbiome are associated with continuous American ginseng cropping. The alpha diversity of fungi and bacteria was significantly lower in the soils planted with American ginseng than the virgin (non-planted) land. The relative abundance of Fusarium spp. and Ilyonectria spp., known plant root pathogens, was much higher in the soils cropped with American ginseng than the non-planted. On the other hand, a number of bacteria with biodegradation function, such as Methylibium spp., Sphingomonas spp., Variovorax spp., and Rubrivivax spp., had lower abundance in the soils cropped with American ginseng than the non-cropped. In addition, soil pH was lower in the field planted with American ginseng than the non-planted. Accumulation of fungal root pathogens and reduction of soil pH may, therefore, have contributed to the problems associated with continuous monocropping of American ginseng.

Effect of three kinds of natural preservative cocktails on vacuum-packed chilled pork.

The aim of this study was to investigate the effects of three different natural preservatives on the microbial profile, the total volatile base nitrogen (TVB-N), and biogenic amine contents of vacuum-packed chilled pork during storage at 4°C. Solution A comprised of tea polyphenols, chitosan, spice extract, propolis, and nisin. Solution B comprised of clove extract, cassia bark extract, ginger juice, garlic juice, and lactobacillus fermentation solution. Solution C consisted of only lactobacillus fermentation solution. The results indicated that solution A was a good natural preservative with higher bacteria inhibitory effect and higher sensory score than B and C. Besides the effect on appealing color, solution B could inhibit microbial activity although its inhibition effect was not as good as solution A. Thus, solution A could be used as a good preservative in industry. Solution C could inhibit the initial growth of Pseudomonas and partially inhibited the growth of Enterobacteriaceae; however, the content of putrescine in the pork treated with solution C was as high as 30.14 ± 2.89 mg/kg after 21 days of storage at 4°C. Hence, solution C is not an ideal preservative for vacuum-packed chilled pork.