Genomic and Transcriptomic Analyses Reveal Multiple Strategies for Vibrio parahaemolyticus to Tolerate Sub-Lethal Concentrations of Three Antibiotics.

Vibrio parahaemolyticus can cause acute gastroenteritis, wound infections, and septicemia in humans. The overuse of antibiotics in aquaculture may lead to a high incidence of the multidrug-resistant (MDR) pathogen. Nevertheless, the genome evolution of V. parahaemolyticus in aquatic animals and the mechanism of its antibiotic tolerance remain to be further deciphered. Here, we investigated the molecular basis of the antibiotic tolerance of V. parahaemolyticus isolates (n = 3) originated from shellfish and crustaceans using comparative genomic and transcriptomic analyses. The genome sequences of the V. parahaemolyticus isolates were determined (5.0-5.3 Mb), and they contained 4709-5610 predicted protein-encoding genes, of which 823-1099 genes were of unknown functions. Comparative genomic analyses revealed a number of mobile genetic elements (MGEs, n = 69), antibiotic resistance-related genes (n = 7-9), and heavy metal tolerance-related genes (n = 2-4). The V. parahaemolyticus isolates were resistant to sub-lethal concentrations (sub-LCs) of ampicillin (AMP, 512 µg/mL), kanamycin (KAN, 64 µg/mL), and streptomycin (STR, 16 µg/mL) (p < 0.05). Comparative transcriptomic analyses revealed that there were significantly altered metabolic pathways elicited by the sub-LCs of the antibiotics (p < 0.05), suggesting the existence of multiple strategies for antibiotic tolerance in V. parahaemolyticus. The results of this study enriched the V. parahaemolyticus genome database and should be useful for controlling the MDR pathogen worldwide.

Improving the microbiological safety and quality of aquatic products using nonthermal processing.

Spoilage and deterioration of aquatic products during storage are inevitable, posing significant challenges to their suitability for consumption and the sustainability of the aquatic products supply chain. Research on the nonthermal processing of fruit juices, probiotics, dairy products, and meat has demonstrated positive outcomes in preserving quality. This review examines specific spoilage bacteria species and mechanisms for various aquatic products and discusses the principles, characteristics, and applications of six nonthermal processing methods for bacterial inhibition to maintain microbiological safety and physicochemical quality. The primary spoilage bacteria groups differ among fish, crustaceans, and shellfish based on storage conditions and durations. Four metabolic pathways utilized by spoilage microorganisms-peptides and amino acids, nitrogen compounds, nucleotides, and carbohydrates-are crucial in explaining spoilage. Nonthermal processing techniques, such as ultrahigh pressure, irradiation, magnetic/electric fields, plasma, and ultrasound, can inactivate microorganisms, thereby enhancing microbiological safety, physicochemical quality, and shelf life. Future research may integrate nonthermal processing with other technologies (e.g., modified atmosphere packaging and omics) to elucidate mechanisms of spoilage and improve the storage quality of aquatic products.

The combined effects of ultrasound and plasma-activated water on microbial inactivation and quality attributes of crayfish during refrigerated storage.

In this study, a decontamination technology combining ultrasound (US) and plasma-activated water (PAW) was developed to better preserve crayfish. First, the decontamination efficacy of US, PAW and their combinations (UP) on crayfish was quantified after 0, 20, 40, or 60 min of treatments. The total viable count (TVC) was reduced by 0.27-0.77 Log CFU/g after individual US or PAW treatments, while a TVC reduction of 1.17 Log CFU/g was achieved after 40 min of UP treatment. Besides, the changes in psychrotrophic bacteria, lactic acid bacteria, yeasts and molds followed a similar trend to TVC. UP treatments normally resulted in more significant reductions in the natural microbiota of crayfish than US or PAW treatments. Furthermore, the microbial quality, physicochemical properties and sensory properties of crayfish after different treatments were assessed during storage at 4 °C for 12 days. According to TVC and total volatile basic nitrogen (TVB-N) values, the control group became unacceptable from 4 days, US or PAW groups became unacceptable from 6 days, while UP group extended the storage time to 8-10 days. During storage, thiobarbituric acid reactive substances (TBARS) values of all the groups were maintained below 0.5 mg/kg, among which the control group exhibited the highest value (0.39 mg/kg). Moreover, UP treatment effectively retarded the deterioration in color and texture properties of crayfish. Fourier transform infrared (FTIR) spectroscopy analysis indicated that UP treatment decreased the α-helix contents and increased the ß-sheet contents of crayfish proteins, while the structural changes were not evident at the end of storage. Low-field nuclear magnetic resonance (LF-NMR) analysis revealed that UP treatment reduced the water migration and enhanced the stability of bond water in crayfish. In addition, E-nose analysis revealed the protection of UP treatment on the sensory properties of crayfish during storage. This study demonstrated that the combinations of US and PAW treatments effectively accelerated the decontamination of crayfish and contributed to better storage quality.

Effects of deletion of siderophore biosynthesis gene in Pseudomonas fragi on quorum sensing and spoilage ability.

Siderophores are important factors in the spoilage process of Pseudomonas fragi, considered to be one of the main spoilage bacterium of tuna, and the secretion of siderophores is regulated by quorum sensing (QS). This study aimed to construct a mutant with the deletion of the siderophore synthetase gene of P. fragi (MS-10), and to explore its effects on the growth, QS, and spoilage potential of P. fragi. The results showed that the deletion of the siderophore biosynthesis gene slowed down the growth rate of the strain. The apoptosis rate increased by 27.7 % compared with that of the wild-type strain at 4 °C for 48 h. Biofilm formation, extracellular protease expression, and signal molecule production were all significantly lower in the mutant strain compared with the wild-type strain. The total viable count and the histamine content showed that the tuna sterile fish block inoculated with the wild-type strain exceeded the acceptable standards by 5 days and was completely spoiled by 7 days, whereas the mutant strain exceeded the acceptable standards by 6 days and was completely spoiled by 9 days. The pH, texture, and other indicators showed that the variation range of the mutant strain was lower than that of the wild-type strain. The deletion of the siderophore biosynthesis gene reduced the spoilage ability of P. fragi. Based on the results, the development of novel preservation agents targeting the control of the siderophore biosynthesis gene could be a new idea for the preservation of aquatic products.

Multi-Residue Screening of Pesticides in Aquatic Products Using High-Performance Liquid Chromatography-Tandem High-Resolution Mass Spectrometry.

Pesticide residues in aquatic products are of great concern due to the risk of environmental transmission and their extensive use in aquaculture. In our work, a quick screening approach was developed for the qualitative and semi-quantitative screening of 87 pesticide residues in aquatic products. The sample preparation was investigated, including extract solvent, extract methods, buffer salts, lipid removal, cleanup materials and filter membranes for aquatic products. Samples were extracted using a modified QuEChERS procedure, and two clean-up procedures were developed for UHPLC-Q/Orbitrap MS analysis based on the fat content of the aquatic products. The screening detection limits for all studied pesticides were distributed between 1 and 500 µg/kg in the three representative matrices. Seventy-one pesticides could be analyzed with a screening limit between 1 and 25 µg/kg in grass carp and crayfish, sixty-one pesticides could be screened for limits between 1 and 50 µg/kg in crab. The accuracy results showed that recoveries ranged from 50 to 120% for 60, 56 and 52 pesticides at medium-level for grass carp, crayfish and crab, respectively. At high spiking levels, 74, 65 and 59 pesticides were recovered within the range of 50-120% for the three matrices, respectively. The relative standard deviations of most compounds in different matrices were less than 20%. With this method, the local farmed aquatic products were tested for pesticide residues. In these samples, ethoxyquinoline, prometryn and phoxim were frequently detected. The majority of these confirmed compounds did not exceed 2.00 µg/kg. A grass carp with trichlorfon at 4.87 µg/kg and two carps with ethoxyquinoline at 200 µg/kg were detected, indicating the potential dietary risk.

The mechanisms and applications of cryoprotectants in aquatic products: An overview.

Frozen storage technology has been widely used for the preservation of Aquatic products. However, ice crystals formation, lipid oxidation and protein denaturation still easily causes aquatic products deterioration. Cryoprotectants are a series of food additives that could efficiently prolong the shelf life and guarantee the acceptability of frozen aquatic products. This review comprehensively illustrated the mechanism of protein denaturation caused by the ice crystal formation and lipid oxidation. The cryoprotective mechanism of various kinds of antifreeze agents (saccharides, phosphates, antifreeze proteins and peptides) and these cryoprotective structure-activity relationship, application efficiency on the quality of aquatic products were also discussed. Moreover, the advantages and disadvantages of each cryoprotectant are also prospected. Compared with others, antifreeze peptides show higher commercial and application values. While, lots of scientific research works are still required to develop novel antifreeze agent as a versatile ingredient with commercial value, applicable in the aquatic products preservation industry.

Pathogenic risk of Vibrio parahaemolyticus infection in raw aquatic products of animal origin by using sQMRA / 公共卫生与预防医学

Objective To evaluate the risk of disease of Vibrio parahaemolyticus in aquatic products of raw food animals for population in guangzhou,and determine risk management points. Methods VP quantitative detection was carried out in aquatic products of raw food animals sold in Guangzhou from 2009 to 2022.sQMRA was applied to assess Vibrio parahaemolyticus risk of aquatic products of raw food animals. According to stratified analysis based on the pollution of Vibrio parahaemolyticus and evaluation results,carry out risk management and analysis. Results Among the 98 samples were detected positive of VP from 1 343 samples from 2009 to 2022 , with an overall positive rate of 7.30%.The number of Vibrio parahaemolyticus infection cases caused by eating aquatic products of raw food animals in Guangzhou was 3012. If the proportion of raw food is reduced , the number of Vibrio parahaemolyticus infection cases will be significantly reduced. The number of cases caused by eating raw fash will be reduced from 2128 to 217.The detection rate of Vibrio parahaemolyticus in raw fresh water products was much higher than that in marine products. The probability of infection in the population was higher. The number of cases caused by eating raw fash was the highest.The detection rate of Vibrio parahaemolyticus was higher in raw crustaceans and molluscs. The incidence of Vibrio parahaemolyticus infection cases caused by eating raw fash in the four quarters varied from high to low as such sequence ,4.93×10-5 in the three quarters , 2.53×10-5 in the second quarter , 2.40×10-5 in the first quarter ,1.77×10-5 in the fourth quarter . Conclusion The risk of disease of Vibrio parahaemolyticus in aquatic products of raw food animals was higher. The public health education should be done well. Aquatic products should be cooked thoroughly before eating . Reduce the intake of raw aquatic products and avoid cross contamination. Focus on the risks of summer and autumn seasons and seafood such as crustaceans and molluscs. Concentrate on scientific research on Vibrio parahaemolyticus pollution of fresh water products.

Optimization of pretreatment methods for N-nitrosamine compounds in ready-to-eat aquatic products / 预防医学

Objective@#To optimize the pretreatment method of N-nitrosamine compounds in ready-to-eat aquatic products. @*Methods@#Market-sold ready-to-eat aquatic products were collected, homogenized and distilled by steam. The samples were extracted for 10 minutes using dispersive liquid-liquid microextraction (DLLME) with ethanol, trichloromethane and sodium chloride (3.0 g). After centrifugation, the organic phase in the lower layer was collected and subjected to gas chromatography-tandem mass spectrometry (GC-MS/MS). The six common N-nitrosamine compounds were determined in ready-to-eat aquatic products using multiple reaction monitoring mode (MRM) and quantified by the internal standard method. @*Results@#The optimized method exhibited a good linear relationship at concentrations of 10.0 to 500 μg/L for determination of 6 N-nitrosamine compounds (correlation coefficient of greater than 0.999), with 0.05 to 0.60 μg/kg limit of detection, 0.15 to 1.60 μg/kg limit of quantitation, mean spiked recovery rates of 71.8% to 108.9%, and relative standard deviations of 1.4% to 8.6%. N-Nitrosodimethylamine showed the highest detection rate in 20 market-sold ready-to-eat aquatic products (90%), and the detection rates of N-Nitrosopyrrolidine, N-Nitrosodiethylamine and N-dibutylnitrosamine were 15%, 10% and 10%, respectively. @*Conclusion@#Steam distillation combined with DLLME may optimize the pretreatment method of N-nitrosamine compounds in ready-to-eat aquatic products and meet the measurement requirements.

Genomic and Transcriptomic Analysis Reveal Multiple Strategies for the Cadmium Tolerance in Vibrio parahaemolyticus N10-18 Isolated from Aquatic Animal Ostrea gigas Thunberg.

The waterborne Vibrio parahaemolyticus can cause acute gastroenteritis, wound infection, and septicemia in humans. Pollution of heavy metals in aquatic environments is proposed to link high incidence of the multidrug-resistant (MDR) pathogen. Nevertheless, the genome evolution and heavy metal tolerance mechanism of V. parahaemolyticus in aquatic animals remain to be largely unveiled. Here, we overcome the limitation by characterizing an MDR V. parahaemolyticus N10-18 isolate with high cadmium (Cd) tolerance using genomic and transcriptomic techniques. The draft genome sequence (4,910,080 bp) of V. parahaemolyticus N10-18 recovered from Ostrea gigas Thunberg was determined, and 722 of 4653 predicted genes had unknown function. Comparative genomic analysis revealed mobile genetic elements (n = 11) and heavy metal and antibiotic-resistance genes (n = 38 and 7). The bacterium significantly changed cell membrane structure to resist the Cd2+ (50 µg/mL) stress (p < 0.05). Comparative transcriptomic analysis revealed seven significantly altered metabolic pathways elicited by the stress. The zinc/Cd/mercury/lead transportation and efflux and the zinc ATP-binding cassette (ABC) transportation were greatly enhanced; metal and iron ABC transportation and thiamine metabolism were also up-regulated; conversely, propanoate metabolism and ribose and maltose ABC transportation were inhibited (p < 0.05). The results of this study demonstrate multiple strategies for the Cd tolerance in V. parahaemolyticus.

Effect of a chitosan coating incorporating epigallocatechin gallate on the quality and shelf life of bighead carp (Aristichthys nobilis) fillets during chilled storage.

The objective of this study was to investigate the potential application of chitosan coatings incorporating epigallocatechin gallate (EGCG) for preserving fillets of bighead carp during chilled storage. The fillets were coated with acetic acid and glycerol, chitosan, and chitosan-EGCG, respectively, and the changes in their physicochemical, microbiological, and sensory characteristics during storage at 4 °C were determined. Notably, total volatile basic nitrogen, thiobarbituric-acid-reactive substances, and K value of chitosan-EGCG coated fillets sampled on day 15 were 48.04 %, 60.19 %, and 32.91 % lower than untreated fillets, respectively. Microbial enumeration suggested that the inclusion of EGCG significantly improved the inhibitory effect of pure chitosan coating on the proliferation of microorganisms. Furthermore, the chitosan-EGCG coated fillets also performed the best in terms of color, texture, and sensory analysis, and extended the shelf-life of the fillets for at least 6 days. A principal component analysis further confirmed the preserving effect of the chitosan-EGCG coating. Mantel test results suggested that the fillets' organoleptic characteristics strongly correlated with physicochemical and microbiological indicators. Overall, this work provides an effective protocol for food quality control and the extension of shelf life during chilled storage, and it clarifies the relationships between organoleptic characteristics and physicochemical and microbiological indexes.

Diverse Aquatic Animal Matrices Play a Key Role in Survival and Potential Virulence of Non-O1/O139 Vibrio cholerae Isolates.

Vibrio cholerae can cause pandemic cholera in humans. The waterborne bacterium is frequently isolated from aquatic products worldwide. However, current literature on the impact of aquatic product matrices on the survival and pathogenicity of cholerae is rare. In this study, the growth of eleven non-O1/0O139 V. cholerae isolates recovered from eight species of commonly consumed fish and shellfish was for the first time determined in the eight aquatic animal matrices, most of which highly increased the bacterial biomass when compared with routine trypsin soybean broth (TSB) medium. Secretomes of the V. cholerae isolates (draft genome size: 3,852,021-4,144,013 bp) were determined using two-dimensional gel electrophoresis (2DE-GE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques. Comparative secretomic analyses revealed 74 differential extracellular proteins, including several virulence- and resistance-associated proteins secreted by the V. cholerae isolates when grown in the eight matrices. Meanwhile, a total of 8,119 intracellular proteins were identified, including 83 virulence- and 8 resistance-associated proteins, of which 61 virulence-associated proteins were absent from proteomes of these isolates when grown in the TSB medium. Additionally, comparative genomic and proteomic analyses also revealed several strain-specific proteins with unknown functions in the V. cholerae isolates. Taken, the results in this study demonstrate that distinct secretomes and proteomes induced by the aquatic animal matrices facilitate V. cholerae resistance in the edible aquatic animals and enhance the pathogenicity of the leading waterborne pathogen worldwide.

Development of a fully automated analytical platform based on static headspace-gas chromatography-tandem mass spectrometry for the analysis of five N-nitrosamines in dried aquatic products of animal origin.

BACKGROUND: The development of rapid and sensitive monitoring methods for trace N-nitrosamines (NAs) in foodstuffs is essential for mitigating the potential health risks to consumers. In the present study, an analytical platform based on one step fully automated static headspace sampling and gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed and validated for the analysis of N-nitrosamines in dried aquatic products of animal origin. The samples and sodium chloride solution mixture were incubated in a heated headspace vial for analyte evaporation, coupled to automatic sampling and online GC-MS/MS analysis. The proposed method requires minimal sample preparation and organic solvent consumption. Five N-nitrosamines including N-nitroso dimethylamine, N-nitroso methyl ethylamine, N-nitroso pyrolidine, N-nitroso piperidine and N-nitroso diphenylamine were selected as model compounds to optimize the significant factors by a using Box-Behnken design. RESULTS: The optimum conditions achieved limits of detections in the range 0.08-0.29 µg kg-1 , with correlation coefficient over 0.998. Relative recoveries in dried aquatic product sample were in the range 76.9-92.4%, with relative SDs of 1.9-7.2%. CONCLUSION: These results confirm the reliability of the developed method for further application in trace level monitoring of the target analytes in foodstuffs. © 2022 Society of Chemical Industry.

Application of solid-phase extraction: High-resolution mass spectrometry analysis strategy in the characterization and quantification of amide herbicides in aquatic products.

In this study, we developed a new method combining thin-layer ultrasonic extraction, efficient SPE purification, ultra-performance liquid chromatography separation, and high-resolution mass spectrometry characterization for seven amide herbicides in fishery products. In sample preparation, to rapidly increase the contact area between the fish meat and the extractant, the fish meat was smeared on a glass slide. This process resulted in quickly reaching the extraction equilibrium and relatively high extraction efficiency. In data analysis, a strategy for characterization and qualitative analysis was constructed by analyzing the fragmentation of amide herbicides using product ion scans. Isomeric pretilachlor and butachlor were separated chromatographically, while the coeluting isomers, alachlor and acetochlor, could be separated by differences in the fragmentation of their selected precursor ions. This method overcame the challenge of poor dispersion in the extractant caused by the high viscosity of fish meat, and the challenge of separation and characterization for isomers. Compared with other methods, the extraction efficiency was improved and the amide herbicides in aquatic products was characterized and quantified rapidly and accurately. Moreover, the qualitative information was much greater and provided an additional strategy for analytes identification. This rapid and accurate method will benefit workers involved in monitoring fishery.

Preparation of Monoclonal Antibody against Pyrene and Benzo [a]pyrene and Development of Enzyme-Linked Immunosorbent Assay for Fish, Shrimp and Crab Samples.

Polycyclic aromatic hydrocarbons (PAHs) are significant environmental and food pollutants that can cause cancer. In this work, a specific monoclonal antibody (mAb) to identify pyrene (PYR) and benzo [a]pyrene (BaP) was prepared, and an indirect competitive enzyme-linked immunoassay (ic-ELISA) was established to detect PYR and BaP residues in living aquatic products for the first time. The effects of complete antigens with different coupling ratios on the production of high-sensitivity mAb was explored. Under the optimal conditions, the IC50 value was 3.73 ± 0.43 µg/L (n = 5). The limits of detection (LODs) for PYR and BaP in fish, shrimp, and crab ranged from 0.43 to 0.98 µg/L. The average recoveries of the spiked samples ranged from 81.5-101.9%, and the coefficient of variation (CV) was less than 11.7%. The validation of the HPLC-FLD method indicated that the ELISA method set up in this experiment provided a trustworthy tool for PAHs residues detection in aquatic products.

Uncertainty evaluation for determination of anesthetics residues and their metabolites in aquatic products by high-performance liquid chromatography-tandem mass spectrometry / 上海预防医学

ObjectiveThe study aimed to evaluate the measurement uncertainty in the determination of five cacaine anesthetics and their metabolites residues by high-performance liquid chromatography-tandem mass spectrometry （LC-MS/MS）. MethodsThrough the establishment of mathematical model， the sources of uncertainty were analyzed， and various components were quantified and synthesized to evaluate the influence of the uncertainty components on the measurement results． ResultsThe uncertainties of the experiments were mainly derived from calibration curve fitting， sample pretreatment， recovery rate， standard solution preparation and measurement repeatability. Furthermore， the expanded uncertainty related to the content in shrimp （k=2） was 1.18 μg‧kg-1 at 8.68 μg‧kg-1 for tricaine methanesulfonate （MS-222）， 1.28 μg‧kg-1 at 9.11 μg‧kg-1 for benzocaine， 13.5 μg‧kg-1 at 91.4 μg‧kg-1 for 4-aminobenzoic acid， 12.2 μg‧kg-1 at 91.0 μg‧kg-1 for p-acetylamino benzoic acid， and 11.3 μg‧kg-1 at 95.3 μg‧kg-1 for 3-aminobenzoic acid， respectively. ConclusionThis method is suitable for the uncertainty analysis of cacaine anesthetics and their metabolites determination in aquatic products by LC-MS/MS， and can provide scientific and reliable basis for the measurement accuracy.

High-throughput screening of drug residues in aquatic products by liquid chromatography-electrostatic field track well high resolution mass spectrometry / 上海预防医学

ObjectiveIn order to ensure the food safety of cultured aquatic products in China， strengthen the supervision and improve detection efficiency， a high-throughput screening method for drug residues in aquatic products by mass spectrometry is to be developed. MethodsLiquid chromatography-electrostatic field track well high resolution mass spectrometry and C18 column were used to separate and collect the information of ion fragments and retention time of 195 veterinary drug standards in positive ion mode， and drug residues in aquatic products were extracted by organic solvents. ResultsThe mass spectrum database and detection methods of 195 veterinary drug standards were established， and a pre-treatment method was developed for extracting veterinary drug residues from aquatic products by acetonitrile and ethyl acetate. The detection method was sensitive， accurate， simple and rapid， and the adding standard recovery of more than 80% compounds reached 70%‒110%. ConclusionThe establishment of this method can quickly and massively screen drug residues in aquatic products， provide technical support for food safety risk monitoring and supervision， cope with the increasing demand for aquatic products and aquaculture volume year by year， and provide a theoretical basis for the subsequent development of mass spectrometry high-throughput detection methods.

The Effect of Product Image Dynamism on Purchase Intention for Online Aquatic Product Shopping: An EEG Study.

PURPOSE: The normalization of epidemic prevention and control triggered a fierce scuffle in the e-commerce of fresh food, as well as for aquatic products online shopping. The main difficulty for consumers to buy fresh food online has always been information asymmetry. Previous study reported that the image is still the primary information source to address information asymmetry. Yet, few studies have focused on the image presentation of aquatic products in e-commerce. The current study aims to probe the effect of perceived movement of e-commerce pictures on purchase intention of aquatic products. Further, we examine how consumers' cognitive conflict and emotion occur when purchasing specific aquatic products with different image dynamism. METHODS: Twenty-eight subjects participated in an experiment with a 2-level product category (fresh vs frozen) × 2-level image dynamism (static vs dynamic) design. During the experiment, participants were asked to rate their purchase intention after they browse the experimental stimulus. We recorded subjects' electroencephalograms (EEGs) throughout the experiment. RESULTS: Behaviorally, participants' purchase intention for the dynamic image was significantly greater than that for the static image, regardless of aquatic product categories. At the neural level, we found that dynamic image produced less cognitive conflict and aroused consumers' positive feelings, which were reflected in decreased N2 amplitudes and latency as well as increased LPP (late positive potential) amplitude, respectively. This effect was enhanced for fresh aquatic products. CONCLUSION: Although picture dynamism only increases perceived movement, it can still induce positive emotions toward the product and lead to a greater purchase intention. The current study emphasized the value of the neuroscience method in revealing consumer cognition and emotion duration product evaluation.

Presence of Antibiotic-Resistant Staphylococcus aureus in Fish and Seafood Originating from Points of Sale in the Tri-City Area (Poland).

ABSTRACT: Infections by methicillin-resistant Staphylococcus aureus (MRSA) is gradually increasing in the community. There is a potential public health hazard resulting from S. aureus contamination of seafood, which is mainly due to unhygienic handling, processing, and storage environments. In Poland, the limits provided in European Commission Regulation 1441/2007 refer to the presence of Escherichia coli and S. aureus in shelled and shucked products of cooked crustaceans and molluscan shellfish. This study was designed to evaluate the occurrence of MRSA in samples of fish and seafood from commercial outlets located in the Tri-City area (Poland). In this study, we investigated a 44 food samples, including fish and seafood collected from various retail outlets in the Tri-City area of Poland. The first stage of staphylococcus isolation was initial culture in Giolitti-Cantoni broth. After 24 h, if blackening had occurred at the bottom (or there was general blackening of the medium), the samples were spread plated onto a CHROMagar MRSA base. The cultures were then incubated for 24 h at a temperature of 37°C. Of the 44 samples, 26 were positive for MRSA. The samples most often contaminated with MRSA were cephalopods (6 of 9) and crustaceans (10 of 15), followed by samples taken from mollusks (4 of 7) and fish (6 of 13). The correlation between the species from which the samples were obtained and the presence of S. aureus was not significant (P > 0.05). The high frequency of occurrence of MRSA in these products points to the potential risk of transmission of diseases through the food chain. The results obtained are significant and useful for S. aureus risk assessment programs for aquatic products.

[Human Health Risk Assessment of Phenol in Poyang Lake Basin].

Phenol is widely used in the production of insulation and thermal insulation materials, adhesives, perfumes, coatings for food containers, paints, and pharmaceutical production, and is also widely detected in the aquatic environment. Long-term exposure to phenol can elicit adverse effects, such as skin burn, liver and central system damage. Here, phenol concentrations in the water and aquatic products of Poyang Lake were investigated. Human health risks from phenol to adults and adolescents were also assessed based on local population exposure parameters. The exposure concentration range of phenol in the studied water and aquatic products was not detected (ND)-556.26 ng·L-1 and 11.98-255.51 µg·kg-1, respectively. Human health risk based on drinking water in different areas ranged from 3.80×10-7-8.46×10-5. Higher human health risks from drinking water was detected in the southern area of Poyang Lake and at the confluence of the Yangtze River to the north. Health risks caused by different types of aquatic products ranges 2.65×10-5-1.47×10-4. In particular, human health risks from the consumption of yellow catfish and catfish are an order of magnitude higher than for other aquatic products. Probabilistic risk assessment was also conducted through Monte Carlo simulation to analyze the health risk to the population in the Poyang Lake Basin and assess its sensitivity of different exposure parameters. The 95th percentile health risk of drinking water and aquatic product consumption in the Poyang Lake Basin was calculated as being acceptable. Overall, the concentrations of phenol had the greatest impact on the calculated health risk values. This study provides valuable information for phenol risk management in the Poyang Lake basin.

One step extraction followed by HPLC-ESI-MS/MS for multi-residue analysis of diacylhydrazine insecticides in water, sediment, and aquatic products.

A multi-residue analysis of six diacylhydrazine insecticides in water, sediment, and aquatic products was established by liquid chromatography triple quadrupole tandem mass spectrometry (LC-MS/MS). The water sample was extracted with acetonitrile by low-temperature enrichment liquid-liquid extraction technology. The sediment and aquatic products were prepared using QuEChERS technique. Method validation showed perfect linearity with correlation coefficients (R) more than 0.9992 for all insecticides, and the matrix effects were nearly negligible (-1.42% to -0.27%) for water, sediment and aquatic products. The recoveries were 80.0-99.7% at three spiked levels (0.02 ng·mL-1, 0.1 ng·mL-1, 0.5 ng·mL-1; 2.0, 10, and 50 ng·g-1) and the precisions (intra-day and inter-day precision) were lower than 5.28%, with the low LODs (3.8 ~ 9.6 pg·mL-1; 0.38-0.96 ng·g-1) and LOQs (12.7 ~ 32.0 pg·mL-1; 1.27-3.20 ng·g-1) for water, sediment, and aquatic products, indicating the good accuracy and precision of the proposed method. The applicability, efficiency, and sensitivity of this method have been proved in the analysis of six diacylhydrazine insecticides in water, sediment, and crucian carp in Rice- crucian carp - integrated planting system.