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AimsBeads containing heat-inactivated bacterial biomaterial (BBBs) were prepared for removal of cypermethrin (CPM) and the conditions for this removal were evaluated and optimized via single-factor coupled orthogonal experiments based on five factors. The adsorption characteristics of BBBs and the binding mechanism were then explored.Methods and ResultsResults showed that the adsorption rate of CPM could reach 98% with beads prepared under optimized conditions: equal volumes of Lactobacillus cell debris derived from 1×1011 CFU; 2% hydroxypropyl-β-cyclodextrin and 2.5% activated carbon concentration, were mixed to give mixture TM, and this and SA, was mixed 1:4 with sodium alginate (SA) and beads were prepared using a 26-Gauge needle). The best adsorption conditions were initial CPM concentration of 10 mg l-1, incubation time of 24 h, and rotational speed of 180 rpm. BBBs have a well-formed structure and abundant surface functional groups, such as –COOH, –OH, –NH, –CH, –CO, –C=C. The adsorption process conformed to pseudo-second-order kinetic, and it was also a Freundlich monolayer adsorption, and the calculated maximum adsorption capacity was 9.69 mg g-1 under optimized conditions.ConclusionsBBBs showed the highest CPM removal capacity and a good tolerance ability.Significance and Impact of the StudyOur results provided a theoretical foundation for developing an adsorbent with heat-inactivated Lactobacillus plantarum (L. plantarum) RS60 for removing CPM in wastewater or drinks.

Pesticides introduced inadvertently or deliberately into environment by anthropogenic activity have caused growing global public concern, therefore the search of approaches for elimination of such xenobiotics should be encouraged. A cypermethrin-degrading bacterial strain Bacillus licheniformis B-1 was found to efficiently degrade carbaryl in LB medium at concentrations of 50–300 mg L−1 within 48 h, during which temperature and pH played important roles as reflected by increase in pollutant depletion. A stimulatory effect of Fe3+ and Mn2+ on microbial growth was observed, whereas Cu2+ caused inhibition of degradation. Results showed that 1-naphthol was a major transformation product of carbaryl which was further metabolised. An approximately 29 kDa carbaryl-degrading enzyme was purified from B-1 with 15.93-fold purification and an overall yield of 6.02% was achieved using ammonium sulphate precipitation, DEAE-Sepharose CL-6B anion-exchange chromatography and Sephadex G-100 gel filtration. The enzyme was identified through nano reversed-phase liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry as a phosphodiesterase (PDE). This is the first report on the characterization of carbaryl-degrading by Bacillus spp. and the role of a PDE in carbaryl-detoxifying. Also, strain B-1 showed versatile in carbosulfan, isoprocarb and chlorpyrifos degradation, demonstrating as ideal candidate for environment bioremediation.

3-PBA is a major degradation intermediate of pyrethroids. Its widespread existence in the environment poses a severe threat to the ecosystem and human health. This study evaluated the adsorption capacity of L. plantarum RS20 toward 3-PBA. Batch adsorption experiments indicated that the optimal adsorption conditions were a temperature of 37 °C and initial pH of 6.0–8.0, under which the removal rate was positively correlated with the cell concentration. In addition, there was no link between the incubation time and adsorption rate. The kinetic study showed that the adsorption process fitted well with the pseudo-second-order model, and the adsorption isotherms could be described by both Langmuir and Freundlich equations. Heat and acid treatments showed that the ability of strain RS20 in removing 3-PBA was independent of microbial vitality. Indeed, it was involved with chemisorption and physisorption via the cell walls. The cell walls made the highest contribution to 3-PBA removal, according to the adsorption experiments using different cellular components. This finding was further reconfirmed by SEM. FTIR spectroscopy analysis indicated that carboxyl, hydroxyl, amino groups, and –C–N were the functional sites for the binding of 3-PBA. The co-culture experiments showed that the adsorption of strain RS20 enhanced the degradation of 3-PBA by strain SC-1. Strain RS20 could also survive and effectively remove 3-PBA in simulated digestive juices. Collectively, strain RS20 could be employed as a biological detoxification agent for humans and animals by eliminating 3-PBA from foods, feeds, and the digestive tract in the future.

The spoilage microbiology in Paocai (fermented vegetables) affects not only the quality of this popular traditional Chinese food but also its safety. This study aimed to isolate and identify the microorganisms commonly leading to spoilage in homemade Paocai from the Sichuan region and, further, to scientifically assess the impact of these microorganisms on product quality and safety. Seven putrid Paocai samples were collected from 7 families in different Sichuan cities. From these, 45 strains were isolated by means of a nutrient agar medium and rose bengal agar. All of the 22 strains (5 fungi and 17 bacteria) with different colonial morphologies and corruption phenomenon in Paocai were determined 16S rDNA/18S rDNA gene sequences. Bacteria were identified as Bacillus spp. (16 strains) and Staphylococcus saprophyticus (1 strain), while the 5 fungi were identified as Candida spp. (3 strains), Kodamaea ohmeri (1 strain), and Geotrichum candidum (1 strain). Based on the results of identification, 7 representative strains of different species were determined as the spoilage characteristics in paocai. All the representative strains metabolized to produce nitrite. Strain SPF21 (K. ohmeri) has a particularly serious impact on the crunchiness of Paocai; however, strains SPF19 (Bacillus subtilis) and SPF21 have the greatest influence on its color. All five of the fungi were seen to form a film on the surface of the Paocai, with SPF5 (G. candidum) exerting the most extreme influence. The growth characteristics in the broth showed that all the representative strains investigated metabolized most of the carbohydrates and were able to tolerate the salinity and acidity of the ordinary homemade Paocai. Moreover, these strains were found to have obvious impacts on the volatile components of Paocai, especially SPF2 and SPF8, with higher dimethyl disulfide and dimethyl trisulfide, which were found to have a pungent odor when highly concentrated.

A highly selective and effective method was successfully developed using magnetic molecular imprinted polymers (MMIPs) as solid-phase extraction (SPE) coupled with high performance liquid chromatography-ultraviolet detector (HPLC-UV) to rapidly determine cephalexin (CFX) in complex animal-derived food. MMIPs were creatively synthesized via suspension polymerization using Fe3O4 magnetic nanoparticles as supporter, CFX as template, acrylamide (AM) as functional monomer, and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The MMIPs were characterized using X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). The binding process fitted well with pseudo-second-order model with good selectivity. Scatchard plot analysis suggested that MMIPs have two types of binding sites with the Qmax of 24.18 mg g−1 and 40.25 mg g−1, respectively. And Langmuir model proved that the recognition sites were uniformly distributed in a monolayer on the surface of MMIPs. The methodological assessment showed good applicability of MMIPs with excellent recovery (85.5%–94.0%), precision (1.2%–2.4%), and stability (intra-day 1.3%–3.6%; inter-day 2.6%–4.3%) in determining CFX content. In addition, the linearity of the calibration curve was good in the range of 0.02–5.00 mg L−1, with a sensitive detection limit of 5.00 μg kg−1. The results above suggest that the obtained MMIPs exert good performance for separation of CFX in animal-derived food, and the proposed method is suitable for the reliable determination of CFX in complex samples.

Vinegar is consumed worldwide as a food condiment, especially in the Chinese diet. The present study optimized the addition of A. niger biofortified-bran Qu (0.3%, 0.45%, and 0.6%) as additional starter to improve total acid content and starch utilization rate in industrial-scale Baoning vinegar production. In addition, this novel study determined the quality and microbial community changes of Baoning vinegar during three-round biofortification in industrial scale. Our results indicated that A. niger biofortified-bran Qu added at 0.6% resulted in higher total acid content and starch utilization rate of vinegar Pei. Biofortification imposed minor changes in the microbial community during three-round biofortification, and more variation was observed in fungal community than that in bacterial community. Most importantly, the quality of Baoning vinegar remained relatively stable. This information further confirmed the feasibility of multiple rounds of A. niger biofortification, and can be used to provide theoretical basis for industrial-scale production.

Cypermethrin (CY) is a synthetic pyrethroid widely used to control insect pests and it elicits a toxic effect on the human body. In this study, Bacillus licheniformis B-1 isolated from tea garden soil was used to degrade CY effectively. A specific enzyme was mainly localized in the extracellular compartments of B-1. This enzyme was identified as an esterase that could be produced without CY. The enzyme was purified 23.03-fold to apparent homogeneity with 8.38% overall recovery by ammonium sulfate precipitation, anion exchange chromatography, and gel filtration chromatography. The molecular mass of the CY-degrading enzyme was 66.4 kDa, and its optimal pH and temperature were 8.5 and 40 °C, respectively. Appropriate Zn2+ , Mn2+ , Mg2+ , Tween 80, SDS, Triton X-100, and BSA concentrations could greatly increase the activity of this enzyme. By contrast, EDTA, 1,10-phenanthroline, NaF, and PMSF strongly inhibited its activity. The purified enzyme showed Km and Vmax values were 5.532 nmol/mL and 33.445 nmol/min. The CY residue in lettuce and cherry tomatoes could be removed more than 50% under the conditions of the treatment concentration for 500 mg/L and the enzyme preparation dilution of 100 times. These results suggested that the CY-degrading enzyme, a constitutive enzyme that mainly exists in the extracellular space, was a novel esterase that might be used to detoxify CY, and could remove CY in vegetables effectively. PRACTICAL APPLICATION: Our research found a novel cypermethrin-hydrolyzing esterase from Bacillus licheniformis B-1 and proved that the enzyme could remove cypermethrin in vegetables effectively.

Cypermethrin is a common food contaminant and environmental pollutant that cause health threats to animals and humans. In this study, the characterization, mechanism, and application of cypermethrin removal by Saccharomyces cerevisiae were investigated. The binding of cypermethrin by the strains S. cerevisiae YS81 and HP was rapid and reached equilibrium at 2–8 h. The removal efficiency was dependent on incubation temperature and yeast concentration, whereas cypermethrin binding was not affected by pH. Heat and acid treatments enhanced the binding ability. Both strains survived in simulated digestion juices and removed cypermethrin effectively under simulated gastrointestinal conditions. Among the strains tested, the YS81 strain was the better candidate for cypermethrin concentration reduction. For the two S. cerevisiae strains, the biosorption kinetics and isotherm followed the pseudo-second-order model and Langmuir model well. The cell walls and the protoplasts were the main yeast cell components involved in cypermethrin binding. Fourier transformed infrared spectroscopy analysis revealed that –OH, –NH, –C–N, –COO−, and –C–O played a major role in binding cypermethrin. Inactive cells effectively removed cypermethrin from apple and cucumber juices and did not affect the physico-chemical properties. Therefore, S. cerevisiae strains YS81 and HP may be used for cypermethrin reduction in food or feed.

To improve the quality of Chinese traditional Paocai, two psychrotolerant lactic acid bacteria (LAB) strains were isolated from Paocai, and the quality of Chinese Paocai product using these two strains as starter cultures was compared to a control sample fermented with aged brine at 10 °C. The results suggested that the physicochemical and sensory features of Paocai fermented with psychrotolerant LAB were more suitable for industrial applications. The nitrite content of Paocai fermented with psychrotolerant LAB was 1 mg/kg, which was significantly lower than that of the control Paocai (P < 0.05). Low-temperature fermentation with the starter cultures of psychrotolerant LAB could effectively prevent overacidity and over-ripening of the Paocai products. Additionally, Paocai fermented with psychrotolerant LAB harbored relatively simple microbial flora as revealed by polymerase chain reaction-denaturing gradient gel electrophoresis. This study provides a basis for improving the quality of Chinese traditional Paocai and the large-scale production of low-temperature Chinese traditional Paocai products.

Biochemical oxygen demand (BOD) sensors based on Zr (IV)-loaded collagen fiber (ZrCF), a novel material with great porous structure, were developed. This novel material shows adsorbability by microorganisms. Saccharomyces cerevisiae and Escherichia coli were used for the construction of BOD sensors. Factors affecting BOD sensor performance were examined. The ZrCF-based BOD sensor showed different sensitivities and linear response ranges with different biofilm densities. The amount of microorganisms strongly affected the performance of the BOD sensor. Poor permeability of previously reported immobilization carriers were greatly circumvented by ZrCF. The service life of the ZrCF-based BOD sensor was more than 42 days. The immobilized microorganisms can be stored for more than 6 months under 4 °C in PB solution. There was good correlation between the results of the sensor method and the standard 5-day BOD method in the determination of pure organic substrates and real water samples.

Additional file 1 : Table S1 Elemental composition of soil with different degree of deterioration from Jinsha earthen site as determined by Scanning electron microscope - energy dispersive spectrometer (SEM-EDS). Table S2 The proportions of ten most abundant bacterial phyla in soil with different degree of deterioration from Jinsha earthen site. S1, no obvious deterioration; S2, mild deterioration; S3, moderate deterioration; S4, severe deterioration. Table S3 The proportions of ten most abundant bacterial genera in soil with different degree of deterioration from Jinsha earthen site. S1, no obvious deterioration; S2, mild deterioration; S3, moderate deterioration; S4, severe deterioration. Table S4 The proportions of fungal phyla in soil with different degree of deterioration from Jinsha earthen site. S1, no obvious deterioration; S2, mild deterioration; S3, moderate deterioration; S4, severe deterioration. Table S5 The proportions of thirty most abundant fungal genera in soil with different degree of deterioration from Jinsha earthen site. S1, no obvious deterioration; S2, mild deterioration; S3, moderate deterioration; S4, severe deterioration. Table S6 The mineral and chemical components at Jinsha earthen site, Chengdu, China. Data from Li (2007). Figure S1 The rarefaction curves of bacterial (a) and fungal (b) operational taxonomic units (OTUs) in soil with different degree of deterioration from Jinsha earthen site. Figure S2 Differentially abundant bacterial (a) and fungal (b) taxa in soil with different degree of deterioration from Jinsha earthen site. S1, no obvious deterioration; S2, mild deterioration; S3, moderate deterioration; S4, severe deterioration.

Background: Jinsha earthen site in Chengdu, China, plays an important role in understanding the ancient culture and history of Shu civilization. The site is undergoing soil degradation due to physical, chemical and biological factors, while very little is known about the influence of biological factors on earthen sites. To investigate the biological factor, we analyzed microbial communities and physicochemical properties from samples with no obvious, mild, moderate and severe degradation, referred to as S1, S2, S3 and S4 sample groups, respectively.Results: Amplicon sequencing targeting the 16S rRNA gene and ITS for bacteria and fungi, respectively, revealed high bacterial and relatively low fungal diversity; the bacterial OTUs were assigned into 36 phyla and 617 genera and the fungal OTUs into 5 phyla and 205 genera. The relative abundances of Bacteroidetes, Proteobacteria and Firmicutes were higher and that of Actinobacteria lower with higher degree of degradation. In the genus level, the relative abundances of Bacteroides and Ralstonia were higher and that of Rubrobacter lower with higher degree of degradation. The distribution of the fungal genera in the four sample groups seemed more random than that of bacteria; however, the relative abundance of the yeast genus Candida was highest in the severely degraded sample group. For both bacteria and fungi, the differences in community composition were associated with differences in EC, moisture, pH, and the concentrations of NH 4 + , K + , Mg 2+ , Ca 2+ and SO 4 2- .Conclusion: Taken together, the microbial communities in soil with different degree of degradation were distinctly different at Jinsha earthen site, and degradation was accompanied with bigger changes in the bacterial than in the fungal community.

Magnetic molecular imprinted polymers with ionic liquid used as an auxiliary solvent (IL@MMIPs) for the recognition of the methyl carbamate pesticide carbaryl (CBR) in foodstuff have been synthesized. The properties and application of IL@MMIPs were determined. The kinetic and isotherm adsorption processes were found to follow the pseudo-second-order and the Scatchard models, respectively. The selective experiment showed that the IL@MMIPs exhibited good selectivity to CBR compared to magnetic nonimprinted polymers with IL (IL@MNIPs). By using the IL@MMIPs as an adsorbent for the enrichment of CBR in food samples, the limit of detection (LOD, S/N = 3) and the limit of quantitation (LOQ, S/N = 10) of this method were 3 μg kg−1 and 10 μg kg−1, respectively. Compared with the traditional method, the IL@MMIP method has better recoveries (83.23–99.83%), precision (1.12–2.09%), and stabilization (intraday, 1.08–2.81%; interday, 2.26–3.30%). IL@MMIPs are an ideal adsorbent that could be applied to conveniently detect CBR in complex food, and the proposed method can be considered as a selective and sensitive alternative to traditional methods with affordable cost, avoiding the complex pretreatment procedure.

Objectives With the wide use of heavy metals as feed additives in animal production, little attention has been paid to heavy metal resistance in pathogenic bacteria. This study was performed to investigate the presence of heavy metal resistance genes (HMRGs) in Escherichia coli and Salmonella isolates and its correlation with disinfectant resistance genes (DRGs) and antibiotic resistance genes (ARGs). Methods HMRGs of 178 E. coli and 294 Salmonella isolated from chicken broiler farms and retail meat were detected by PCR. Minimum inhibitory concentrations (MICs) of heavy metals were determined by the broth microdilution method. The complete genome of E. coli E308, which had indications of multidrug resistance, was recovered and assembled using third-generation sequencing. Results The frequency of different HMRGs in E. coli and Salmonella ranged from 0.60–77.0% and 0.30–87.1%, respectively. MICs of heavy metals for E. coli and Salmonella ranged widely from ≤12.5 mg/L to 1600 mg/L. Moreover, HMRGs (zntA, arsB, merA, pcoR, pcoA, pcoC and chrA) were found to be significantly associated with one or more DRGs [sugE(c), emrE, mdfA, ydgE/ydgF, qacF, sugE(p) and qacEΔ1] and ARGs (sul1, sul2, sul3, tetA, tetB, tetC, blaTEM, blaSHV and blaCTX) (P Conclusion This study demonstrated that HMRGs are widely present in E. coli and Salmonella isolated from chicken farms and retail meat. The association between HMRGs with DRGs and ARGs may lead to co-resistance to heavy metals and other antimicrobial agents.

The authors have synthesized a phosphorescent probe of type SiO2-QD-MIP, where QD stands for Mn:ZnS quantum dots and MIP is a polymer coating that was molecularly imprinted with cephalexin. The nanoprobe with high specificity was prepared via sol-gel polymerization using thioglycolic acid (TGA)-modified QDs as luminescent materials, cephalexin as the template, 3-aminopropyltriethoxysilane as the functional monomer, and tetraethoxysilane as the crosslinking agent. The SiO2-QD-MIPs were characterized by X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectrometry. The orange emission of the probe, with excitation/emission maxima at 295/590 nm, decreases linearly in the 2.5–50 μg·L−1 cephalexin concentration range with a limit of detection (LOD) of 0.81 μg·L−1. The nanoprobe was successfully applied to the determination of cephalexin in (spiked) raw milk and milk powder. The recoveries ranged from 91.7 to 103.7%.

The purpose of this study was to evaluate the inhibitory mechanism of cell-free supernatants of Lactobacillus plantarum (LCFS) on Proteus mirabilis and estimate the expression of histamine synthesis-related genes. The minimum inhibitory concentration (MIC) of the LCFS and antibacterial curve assay was determined by the tube double-dilution method. The antibacterial mechanism was explored by cell integrity, morphology, and structure of P. mirabilis. Further, the expression of the histidine decarboxylase (hdcA) gene and histidine/histamine antiporter (hdcP) gene of P. mirabilis and the intracellular and extracellular contents of histidine and histamine were determined. The MIC of the LCFS was 12.5 mg/mL, and the antibacterial curve assay showed an inhibited growth of P. mirabilis. The increase in the Alkaline Phosphatase (AKP) content, membrane permeability, and potential indicated the destruction of the cytoplasm, cell membrane, and cell wall of P. mirabilis. The results of SEM and TEM revealed that the LCFS disrupted the normal morphology and structure of the cell. Moreover, differences in the extracellular and intracellular histidine and histamine content between the MIC group and the control group was consistent with the decreased expression of hdcA and hdcP genes in the MIC group observed in the previous antimicrobial studies. Hence, the inhibitory mechanism of LCFS on histamine formation was clarified at cellular and molecular levels.

In this study, the cypermethrin binding characteristics of lactic acid bacteria were investigated for the first time. Two strains, Lactobacillus plantarum RS60 and Pediococcus acidilactici D15, possessed the highest cypermethrin removal capacity and good tolerance to simulated digestive juices. They were employed for further studies on cypermethrin binding characteristics. 55.06% and 56.46% of cypermethrin were removed within 0.25 h by strains RS60 and D15, respectively. The effect of pH on binding capacity was negligible. Heat treatment enhanced cypermethrin binding rate. Moreover, inactive cells were capable of removing cypermethrin from fruit and vegetable juices, with over 60% cypermethrin reduction within 2 h. No adverse effect was found on the quality of juice during the biosorption process. Besides, these two strains also could bind other several pyrethroids and 3-phenoxybenzoic acid. These findings indicated that L. plantarum RS60 and P. acidilactici D15 may be useful to reduce cypermethrin in contaminated foods.

This paper reports the development of a novel probe based on magnetic room-temperature phosphorescence quantum dots with molecularly imprinted polymers (MQD-MIPs) for the rapid detection of trace norfloxacin (NFX) residual in complex food matrix. The highly selective probe was constructed by surface molecular imprinting technology using magnetic materials (Fe3O4 nanoparticles) as core, Mn-doped ZnS quantum dots (Mn-ZnS QDs) as phosphorescent materials, NFX as template, 3-aminopropyltriethoxysilane as functional monomer, and tetraethoxysilane as crosslinking agent. The as-obtained MQD-MIPs were characterized in detail by transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectrometry, and vibrating sample magnetometer. A magnetic strength of 37.64 emu g−1 was recorded. Also, the probe displayed excellent room temperature phosphorescence properties with excitation/emission peaks at 300/590 nm. Under the optimized conditions, the detection time was less than 40 min, phosphorescence intensity varied linearly with concentration from 1 to 90 μg·L−1, and detection limit reached as low as 0.80 μg·L−1. Furthermore, the MQD-MIPs-based probe successfully detected norfloxacin residues in spiked fish and milk samples with recoveries of 90.92–111.53% and RSD

To further improve the utilization rate of starch in the fermentation of Baoning vinegar, the effects of Aspergillus niger biofortification on the quality and microbial community of vinegar Pei (a mixture of fermentation materials) and Baoning vinegar were evaluated. The results suggested that the total acid content, a crucial parameter for vinegar production, in vinegar Pei increased by approximately 1.70 g/100 g at the end of fermentation. The utilization rate of starch and content of organic acid increased significantly after biofortification, and the content of lactic acid was the highest in Baoning vinegar, followed by acetic acid. Similarly, the total amount of free amino acids increased after biofortification, especially the content of histidine and tyrosine. The esters and acid compounds were the most abundant in the vinegar Pei, while the contents of acid and carbonyl compounds were the highest in liquid vinegar. As revealed by high-throughput sequencing, the microbial community in vinegar Pei changed little after biofortification. Lactic acid bacteria and yeast are the most abundant microbes throughout the fermentation process. The present study provides insights into the improvement of the solid-state brewing process of vinegar.

The strain Y1, with a notably high production of neutral protease, was isolated from naturally fermented broad beans and subsequently identified as Aspergillus oryzae, through the analysis of its morphology characteristics and 18S rDNA sequence. Naturally fermented broad beans are the main raw material in Sichuan broad-bean sauce. The neutral protease from Aspergillus oryzae Y1 was purified using ammonium sulphate precipitation and DEAE-Sepharose Fast Flow chromatography, which resulted in a 10.0-fold increase in the specific activity (2264.3 U/mg) and a recovery rate of 21%. The estimated molecular mass of the purified protease was approximately 45 kDa. The optimal pH and temperature of the purified protease were 7.0 and 55 °C, respectively. The heat resistance of the purified protease was significantly higher than the commercial protease. The effect of metal ions on the activity of the purified protease approximated that of commercial neutral protease. Furthermore, the maximum hydrolysis rate (V max) and apparent Michaelis–Menten constant (K m) values of the purified protease were 256.4103 μg/mL min and 20.0769 mg/mL, respectively. The purified protease had a higher affinity for the substrate than the commercial neutral protease. All the results suggest that this neutral protease exhibits the potential for application in industry due to its good resistance to high temperatures and wide range of acids and bases.

In this study, an efficient, selective, and simple analytical method for the extraction of chloramphenicol (CAP) from food using magnetic molecularly imprinted polymers (MMIPs) as the solid-phase extraction (SPE) sorbent was successfully developed. MMIPs with varying ratios of methacrylic acid to acrylamide were prepared by suspension polymerization on the surface of double-bond-modified Fe3O4 magnetic nanoparticles. Further, these MMIPs were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy, as well as using a vibrating sample magnetometer. Furthermore, the adsorption capacities of MMIPs and MNIPs were investigated by binding experiments. Methodology evaluation for the detection of CAP from food was carried out using MMIPs as the SPE sorbent. By using an external magnetic field, MMIPs were separated by a simple and rapid method. The diameter of the so-obtained MMIPs, exhibiting good monodispersity, was 400–700 nm. The MMIPs exhibited the maximum apparent adsorption capacity of up to 42.60 mg g−1 with good selectivity. For the detection of food samples, the linear response range was 0.02–10.00 mg L−1, with a detection limit of 10 μg L−1, and intra- and inter-day stabilities ranged from 1.34% to 1.89% and from 1.76% to 2.77%, respectively, with good recoveries (95.31%–106.89%) and satisfactory relative standard deviations (1.21%–2.60%).

Chicken products with high water and nutrient contents provide essential nutrients for microbial growth. This study was designed to determine the effect of lactic acid-based spray washing. First, the reduction of microbial counts on chicken carcasses was evaluated through lactic acid-based spray washing. Second, bacterial diversity on chicken carcasses in different steps in a chicken-slaughtering chain was investigated through polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The effect of spray washing on quick-frozen chicken quality was also examined. Results revealed that microbial counts decreased significantly after the chickens were spray-washed with 1.5% lactic acid at 50 °C for 15s. PCR-DGGE revealed a decrease in microbial counts of several bacterial species, such as uncultured bacterium, uncultured Clostridiales sp., Pseudomonas fluorescens , Ruminococcus sp., and uncultured Ruminococcus sp. The spray washing performed did not remarkably affect the pH and total volatile basic nitrogen of quick-frozen chicken during storage. Therefore, the proposed technique may be applied to chicken-slaughtering chains and may be used to investigate bacterial diversity on chicken carcasses.

We extracted collagen (CL) from the scales of Ctenopharyngodon idella and fabricated a CL self-assembly film. Catalase (CAT) was immobilized on the films using cross-linking, adsorption, and embedding methods. The activity and operational stability of immobilized CAT were investigated, along with the influence of the concentration of glutaraldehyde (GTA) and of the initial concentration of embedded CAT. The results showed that the CL triple helix remained intact. Differential scanning calorimetry data showed that the thermal stability of CL was significantly improved by neutral salt-induced self-aggregation and GTA cross-linking. The immobilized enzyme had high activity and good operational stability. When the enzyme concentration reached 0.5 mg/mL, immobilized enzyme activity of grass carp scales reached a maximum of 2596 U/g, and after twenty-two uses, enzyme activity remained above 50%, and it could be reused >45 times (CAT = 0.5 mg/mL, GTA = 5%, Temperature = 30 °C, pH = 7). Moreover, the optimum temperature and pH of immobilized CAT were 35 °C and 7, respectively, while the same for free CAT was 30 °C and 7, respectively. This indicated that immobilization of CAT has a protective effect.

A total of 189 Salmonella isolates were recovered from 627 samples which were collected from cecal contents of broilers, chicken carcasses, chicken meat after cutting step and frozen broiler chicken products along the slaughtering process at a slaughterhouse in Sichuan province of China. The Salmonella isolates were subjected to antimicrobial susceptibility testing to 10 categories of antimicrobial agents using the Kirby-Bauer disk diffusion method. Those antibiotics-resistant isolates were further investigated for the occurrence of resistance genes, the presence of class 1 integron as well as the associated gene cassettes, and the mutations within the gyrA and parC genes. Consequently, the prevalence of Salmonella was 30.14% (47.96% for cecal content, 18.78% for chicken carcasses, 31.33% for cutting meat and 14.00% for frozen meat, respectively). The predominant serotypes were S. Typhimurium (15.34%) and S. Enteritidis (69.84%). High resistance rates to the following drugs were observed: nalidixic acid (99.5%), ampicillin (87.8%), tetracycline (51.9%), ciprofloxacin (48.7%), trimethoprim/sulfamethoxazole (48.1%), and spectinomycin (34.4%). Antimicrobial resistance profiling showed that 60.8% of isolates were multidrug resistant (MDR), and MDR strains increased from 44.7% to 78.6% along the slaughtering line. 94.6% (n=157) of beta-lactam-resistant isolates harbored at least one resistance gene of blaTEM or blaCTX-M. The relatively low prevalence of aminoglycoside resistance genes (aac(3)-II, aac(3)-IV, and ant(2″)-I) was found in 49 (66.2%) of antibiotic-resistant isolates. The tetracycline resistance genes (tet(A), tet(B), tet(C), and tet(G) and sulfonamide resistance genes (sul1, sul2, and sul3) were identified in 84 (85.7%) and 89 (97.8%) antibiotic-resistant isolates respectively. floR was identified in 44 (97.8%) florfenicol-resistant isolates. Class 1 integron was detected in 37.4% (n=43) of the MDR isolates. Two different gene cassettes, blaOXA-30-aadA1 (19 isolates) and blaOXA-30-aadA1/drfA1-orfC (2 isolates), were identified in class 1 integron-positive isolates. 97.9% (184/188) of quinolone-resistant isolates had at least one mutation within gyrA or parC. Overall, antimicrobial resistance showed an increasing trend along the slaughtering process. The results showed that broiler chicken products in the slaughterhouse were contaminated with MDR Salmonella, which might originate from food producing animals to some extent, and cross-contamination during slaughter, and facilitate the dissemination of the resistance genes to consumers along the production chain, which suggests importance of controlling Salmonella during slaughter for public health, underlying strict hygiene method and HACCP management to reduce cross-contamination.

The exopolysaccharides (EPS) produced by Se-enriched Lactobacillus plantarum BC-25 was purified to illustrate its structure and conformational characterization. The yield of EPS (324.80mg/l) was obtained with a sodium selenite concentration of 6μg/ml. The results indicated that the EPS was soluble in water, but insoluble in organic solvents. The molecular weight of this highly thermal stability EPS was 1.83×10(4)Da and 1.33×10(4)Da with or without Se enriched respectively. The EPS was composed of mannose, galactose and glucose in a molar ratio of 92.21:1.79:6.00 and 91.36:2.44:6.20 with or without Se. This compound had a backbone of (1→2)-linked Man, (1→2.6)-linked Glc, (2→6)-linked Man, and (2→6)-linkedGal confirmed by GC-MS. IR analysis suggested that the EPS belonged to heteropolysaccharide with a pyran group, with possible presence of SeO and CSeC residues that Se may substitutes CH3 in -OCH3 in the polysaccharide as confirmed by NMR spectroscopy.

To investigate the bacteria community and biodiversity of four-years pickled Yanshan Dongcai.We studied the bacterial communities of Dongcai by 16S rDNA diversity analysis and the cultured species isolated from Dongcai sample by Restriction Fragment Length Polymorphism (RFLP) and 16S rRNA gene sequence analysis.The 16S rDNA diversity showed that the bacteria belonged to the phyla Proteobacteria (87.9% ) and Firmicutes (7.1% ), including many moderately halophilic bacteria such as Virgibacillus kekensis, Marinococcus albus, Salinicoccus sp., Lactobacillus halophilus and Halomonas. Only 5% of clone sequences belonged to the phylum Actinobacteria. Thirty-five strains were isolated from Dongcai sample, and 16S rDNA-RFLP analysis indicated that 34 isolates affiliated with the phylum Firmicutes, including Virgibacillus, Bacillus megaterium and Gracilibacillus saliphilus which were moderately halophilic bacteria, but only one isolate belonged to the phylum Actinobacteria.The bacterial diversity is low in Dongcai, dominated by moderately halophilic bacteria.