To study the application of intelligent blockchain technology in the field of food traceability.

This study constructed a system architecture that integrates internet of things (IoT) data collection, blockchain distributed storage and automatic execution of smart contracts. The core smart contract modules such as user verification, data storage and transaction update were designed and implemented; taking the dairy product supply chain as a case, deployment and testing were carried out on the Hyperledger Fabric platform.

Compared to traditional My Structured Query Language (MySQL) clusters, this system reduced the traceability response time from 68.2 h to 8.9 h (a reduction of 86.8%), ensured 100% consistency of data between nodes under normal consensus mechanism operation conditions and reduced the risk of data tampering from 22.1% to 0.7% (a decrease of 96.8%). In addition, a 30 d stability test showed that the system had less than 0.5 daily failures and a node synchronization success rate of over 99.9%.

From this, it can be seen that the collaborative solution of on chain metadata indexing and off chain distributed storage proposed in this study balanced data traceability and system storage scalability. Through modular smart contract design, the automation and trustworthy flow of supply chain data has been achieved, providing feasible technical solutions and empirical evidence for building an efficient, transparent and trustworthy food traceability system.

To investigate the contamination characteristics, serotype distribution and drug resistance of Salmonella in food sold in Zibo City, Shandong Province.

According to the National food contamination and hazardous factors risk monitoring manual, Shandong Province food contaminant and harmful factor risk monitoring work manual and GB 4789.4—2016 Food microbiological examination-Salmonella inspection.Isolation, identification and serotyping of Salmonella from 19 kinds of and 1812 food samples collected from 2015 to 2024. The antibiotic drug types were determined by referring to the recommendations of the Clinical and Laboratory Standards Institute (CLSI), and the minimum inhibitory concentration (MIC) was measured using the micro broth dilution method.

A total of 131 strains of Salmonella were detected, with an overall detection rate of 7.23%(131/1812). Among them, the detection rate of meat and meat products was the highest, reaching 21.02% (95/452), followed by animal aquatic products at 13.96% (31/222). The detection rates were higher in summer and autumn, which were 19.10% (68/356) and 17.48% (54/309) respectively, showing obvious seasonality, and the detection rate in the circulation link (19.43%, 122/628) was significantly higher than that in the catering link (4.39%, 9/205). The main dominant serotypes were Salmonella enteritidis (13.74%, 18/131), Salmonella indiana (8.40%, 11/131) and Salmonella derby (6.11%, 8/131). There were differences in dominant serotypes among foods from different species:Poultry-derived meat products were mainly dominated by Salmonella enteritidis (12.21%, 16/131), pork-derived meat products were mainly dominated by Salmonella derby (5.34%, 7/131), and animal aquatic products were mainly dominated by Salmonella ituri (3.82%, 5/131) and Salmonella aberdeen (3.82%, 5/131). The drug resistance analysis results showed that the overall drug resistance rate of 131 Salmonella strains was 80.15% (105/131), and the proportion of multi-drug resistance was 77.14% (81/105); the highest resistance rate was 67.18% (88/131) for ampicillin, followed by tetracycline (63.36%, 83/131) and trimethoprim/sulfamethoxazole (51.15%, 67/131).

Salmonella contamination in Zibo City is mainly found in meat and meat products, with diverse serotypes and severe drug resistance and multi-drug resistance. Regulatory authorities should strengthen the supervision of meat products, animal based aquatic products, and related breeding processes, and remind consumers to pay attention to food hygiene during the high incidence season of infection to prevent foodborne Salmonella infections.

To establish a method for the determination of residual levels of 6 kinds of novel pesticides (flutianil, ipflufenoquin, mandestrobin, benzpyrimoxan, pyriofenone and pyflubumide) in plant-derived foods by gas chromatography-tandem mass spectrometry (GC-MS/MS).

Samples were extracted by shaking with 1% formic acid in acetonitrile. Anhydrous magnesium sulfate, sodium chloride, citric acid dihydrate and disodium citrate sesquihydrate were then added to the extract; after shaking, the mixture was centrifuged. A quantitative volume of the supernatant was purified using the QuEChERS method, with the purification materials including anhydrous magnesium sulfate (MgSO₄), primary secondary amine, octadecyltrimethoxysilane and graphitized carbon black. After vortex mixing and centrifugation, 2 mL of the supernatant was transferred to a centrifuge tube, concentrated to near dryness under nitrogen, dissolved in 1 mL of n-hexane, and filtered through an organic phase filter membrane before GC-MS/MS analysis. Quantification was performed using a matrix-matched standard curve. In this study, the sample extraction, purification and determination procedures were optimized and discussed.

For the 6 kinds of novel pesticides (including flutianil and ipflufenoquin) in plant-derived foods, the limits of quantitation ranged from 0.005 mg/kg to 0.050 mg/kg, the recoveries were between 71.1% and 119.7%, and the relative standard deviations were 0.6% to 12.8%.

This method is simple, rapid and accurate, and is suitable for the analysis and detection of multi-residues of the 6 kinds of novel pesticides in plant-derived foods.

To investigate the contamination status, molecular characteristics, virulence genes, antibiotic resistance genes and resistance profiles of Listeria monocytogenes (Lm) in foods from Baoshan City.

Whole-genome sequencing was performed on Lm strains isolated from retail foods in Baoshan. The sequences were assembled using BioNumerics 7.6 software, and their molecular characteristics were subsequently analyzed. In parallel, antimicrobial susceptibility testing was conducted on the 12 Lm strains using the broth dilution method.

A total of 229 food samples were collected and analyzed, yielding 12 Lm isolates with an overall contamination rate of 5.24%. No statistically significant difference was observed in Lm detection rates among the 5 food categories (P>0.05), although numerical variations in contamination existed across categories. Similarly, the overall contamination rates across the 5 sampling regions showed no statistically significant difference (P>0.05), despite observable variations among individual regions. The Lm isolated were classified into 2 genetic lineages:Lineage I comprised 7 strains (58.33%), and Lineage II comprised 4 strains (33.33%). One strain isolated from raw meat products remained untyped. They were classified into 3 kinds of serogroups: 1/2a-3a (4 strains, 33.33%), 1/2b-3b-7 (4 strains, 33.33%) and 4b-4d-4e (4 strains, 33.33%). The 6 sequence types (STs) were identified, with ST8(25%) being the dominant type. The isolates fell into 6 clonal complexe (CC), with CC8 (25%) as the predominant group. All isolates carried key virulence genes, with 100% harboring complete LIPI-1 and LIPI-2 gene clusters, while LIPI-3 and LIPI-4 were less frequent (2 and 3 strains, respectively). All isolates carried major resistance genes fosX, mprF, lin and sul. Antimicrobial susceptibility testing revealed resistance rates of 83.33% (10/12) to erythromycin and 33.33% (4/12) to meropenem. The 2 kinds of resistance patterns were observed: 6 strains showed single-drug resistance, and 4 strains showed dual resistance, primarily to erythromycin and meropenem (33.33%, 4/12).

Lm contamination is detected in various retail foods in Baoshan. The isolates exhibits high genetic diversity and included common pathogenic sequence types. All strains universally carry key virulence genes, indicating strong pathogenicity and potential outbreak risk. Moreover, widespread resistance to clinically important antibiotics, such as erythromycin and meropenem, is observed. Strengthened food monitoring across the city, along with standardized clinical and veterinary antibiotic use, is recommended to prevent and control the associated risks.

To establish a novel method for rapid on-site detection of the tetracycline resistance gene TetA by cross priming amplification (CPA) technology.

A total of 5 specific primers targeting conserved regions of the TetA gene were designed. Amplification was performed under isothermal conditions (optimized at 51–60 ℃), with the entire detection process completed within 45–60 minutes using only basic heating equipment such as a water bath or metal bath. To validate its performance, the method was systematically evaluated for sensitivity, specificity and interference resistance.

The limit of detection for purified TetA gene templates was as low as 30.0  fg/μL, indicating high sensitivity. Furthermore, no nonspecific amplification was observed in comparative tests against other tetracycline resistance genes (e.g., tetB, tetM) and common clinical pathogenic genes, confirming excellent selectivity. Additionally, simulated sample testing yielded stable and reliable results.

A simple, rapid, low-cost and instrument-free CPA-based method for TetA gene detection is successfully developed. With its high sensitivity and specificity, this method can effectively meet the needs for rapid on-site screening of tetracycline resistance genes in primary healthcare institutions and farming environments. It provides a robust technical tool for real-time monitoring and controlling the spread of antibiotic resistance genes, demonstrating significant practical application value.

To establish a method for rapid screening of 89 kinds of pesticide residues in foodborne plant extracts by QuEChERS-gas chromatography-tandem mass spectrometry.

Foodborne plant extracts are dispersed with pure water, extracted using acetonitrile, and purified via the QuEChERS method. The analytes are separated on a DB-5MS chromatographic column and detected in multiple reaction monitoring (MRM) mode. The accurate mass-to-charge ratios of precursor ions and product ions are acquired, and quantitative analysis is performed by matrix-matched calibration curve with internal standard method..

The results showed that the linearity of 89 kinds of pesticides and their metabolites was good in the range of 10–200 ng/mL and the correlation coefficients (r²) were greater than 0.99. The limits of quantitation were 2–20 μg/kg. The recoveries of 89 kinds of pesticides in Ganoderma lucidum extract was ranged from 59.9% to 129.1%, with the relative standard deviations of 0.4% to 13.9%.

This method is simple, efficient, accurate and sensitive, and is suitable for the detection of 89 pesticide residues in foodborne-plant extracts.

To study the spatiotemporal distribution and drug resistance of foodborne Salmonella in Zhenjiang Region.

From 2021 to 2024, according to the Jiangsu Province foodborne disease surveillance work manual, stool samples from foodborne diarrhea cases were collected from sentinel hospitals in 4 urban districts of Zhenjiang City. Salmonella isolation and cultivation, serotyping and drug sensitivity tests (using the broth microdilution method) were performed.

Out of 2547 samples of foodborne diarrhea, 117 strains of Salmonella were detected, with a detection rate of 4.59%. Among them, the sample size was larger in summer and autumn, with higher positive detection rates (5.31% and 4.75%). There was a statistically significant difference in the detection rate of Salmonella in different seasons (χ²=6.61, P<0.05). The detection rates of Salmonella in Runzhou District and Danyang City (8.23%, 7.77%) were significantly higher than those in other areas (χ²=66.622, P<0.05). The predominant serotypes in Zhenjiang Area were Salmonella typhimurium (45.30%). The drug resistance rate of Salmonella in this area was high (82.05%). The highest resistance was to ampicillin (82.05%), followed by tetracycline(70.09%) and ampicillin/sulbactam (64.10%), chloramphenicol (52.14%) and so on, and the situation of multidrug resistance was 75.21%, with a multidrug resistance spectrum of 52, mainly ampicillin-ampicillin/sulbactam-tetracycline-chloramphenicol-sulfamethoxazole-trimethoprim (12.50%) and ampicillin-ampicillin/sulbactam-nalidixic acid-polymyxin E (7.95%).

Foodborne Salmonella in Zhenjiang region has a high incidence in summer and autumn, with relatively high detection rates in Runzhou District and Danyang City. The serotypes are diverse, and the strains exhibit high antibiotic resistance rates and complex multidrug resistance spectrum. These results provide a key scientific basis for precise early warning of local foodborne diseases, guidance for empirical clinical medication, and the formulation of antibiotic resistance monitoring policies.