Agricultural product safety form the foundation of constructing food supply systems. Smart hydrogels exhibit promising application prospects in agricultural safety analysis due to their stimuli responsiveness, mechanical stability, biocompatibility, and adjustable pore size. This review focused on the classification, preparation methods, responsive mechanisms and applications of smart hydrogels in agricultural product safety. Based on synthesis methods, they could be divided into physically cross-linked and chemically cross-linked hydrogels, while stimulus-responsive types included temperature-responsive, pH-responsive, biomolecule-responsive, electric field-responsive and magnetic field-responsive hydrogels. This study summarized their applications in contaminants adsorption/separation, foodborne pathogen detection, mycotoxin detection, pesticide/veterinary drug residue analysis, illegal additive identification, and heavy metal detection for agricultural product assurance. Development prospects of smart hydrogels are further discussed to provide references for their expanded utilization in agricultural product safety.

Objective To evaluate the levels of metal elements contamination in Morella ruba Lour. from different production areas in Wenzhou and establish a comprehensive evaluation system. Methods The 121 Morella ruba Lour. samples and 68 soil samples from Morella ruba Lour. planting sites in Wenzhou were studied. The pH of the soil and 6 kinds of metal elements indicators, including chromium, nickel, arsenic, cadmium, mercury and lead, in both the soil and fruits were measured and analyzed. A fruit-soil correlation model (incorporating correlation analysis and principal component analysis of 13 parameters across 54 samples) was established. Results The qualification rate of Morella ruba Lour. samples was 94.21%, while the qualification rate of soil samples was only 39.71%; there was a varying degree of correlation between the metal elements content in Morella ruba Lour. fruits and soil, with a strong positive correlation between mercury in Morella ruba Lour. fruits and chromium and nickel in soil; principal component analysis identified chromium and cadmium in soil, as well as nickel, lead and arsenic in Morella ruba Lour., as the core indicators for evaluating the metal elements quality and safety of Morella ruba Lour.. Conclusion This study established a comprehensive evaluation system for metal elements quality safety in Morella ruba Lour., providing methodological references for regional agricultural product safety regulation.

Objective To screen salt-tolerant esterase-producing strains from yellow water and analyze their metabolic products. Methods Esterase-producing strains were isolated from yellow water and identified using morphological, physiological, biochemical and molecular biological methods. Results The 9 esterase-producing strains were screened from yellow water, among which CZ-1, CZ-5 and CZ-8 were Paenibacillus dendritiformis, CZ-9 was Paenibacillus cookii, CZ-10, CZ-13 and CZ-15 were Bacillus velezensis, and CZ-3 was Saccharomyces cerevisiae, P5-5 was Pichia manshurica. All 9 strains had good salt tolerance and could grow at pH 2.0-11.0, and 7 strains had salt tolerance up to 120 g/L. Experiments showed that when using caproic acid as the substrate, the esterifying enzyme activities of strains CZ-1, CZ-3, CZ-5, CZ-8, CZ-9, CZ-13, CZ-15 and P5-5 were 69.93, 70.62, 6.01, 67.65, 35.31, 48.51, 69.24 and 71.45 U/mL respectively, and strain CZ-10 had no esterifying enzyme activity. Gas chromatography-mass spectrometer analysis showed that 12 kinds of volatile components of alcohols, 7 kinds of volatile components of aldehydes, 1 kind of volatile component of ethers, 3 kinds of volatile components of amines, 11 kinds of volatile components of ketones, 9 kinds of volatile components of esters, 3 kinds of volatile components of acids and 22 kinds of other volatile components were detected in the fermentation broth. Conclusion The 9 esterifying enzyme-producing strains are screened from yellow water, all of which have good salt and alkali tolerance and esterifying enzyme activity. P5-5 has the highest esterifying enzyme activity and the most types of volatile components, which provides a theoretical basis for the subsequent treatment and application of yellow water.

Objective To establish a method for the detection of furosine in milk by microwave hydrolysis-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Methods The optimal conditions for microwave hydrolysis were optimized by single factor experiments and response surface methodology. The hydrolysis solution obtained under the optimal hydrolysis conditions was filtered to a constant volume. The hydrolysate was diluted 10-fold with 6.0 g/L ammonium acetate solution and then analyzed. Gradient elution was performed with 0.1% formic acid aqueous solution and methanol solution as mobile phases, and the separation was carried out on a T3 liquid chromatography column (100 mm×2.1 mm, 1.8 μm). Under the positive ion mode of electrospray ion source (ESI⁺), multiple reaction monitoring (MRM) mode was selected for detection and external standard method was used for quantification. Results The optimal microwave hydrolysis conditions for furosine in milk were hydrolysis temperature of 160 ℃, hydrochloric acid concentration of 8.1 mol/L, and hydrolysis time of 52 min. The primary-to-secondary order of influencing factors was hydrochloric acid concentration>hydrolysis time>hydrolysis temperature. Furosine in milk showed a good linear relationship within the range of 0.005-0.500 µg/mL, with a correlation coefficient (r) of 0.9958. The limit of quantitation (LOQ) and limit of detection (LOD) were 0.20 µg/mL and 0.07 µg/mL, respectively. The average recoveries were 89.09%-97.33%, with relative standard deviations (RSDs) of 3.37%-7.02% (n=6). Conclusion This method is efficient and accurate. Compared with the traditional hydrolysis methods(12-24 hours), microwave hydrolysis shortens the hydrolysis time to 52 minutes, and there is no significant difference (P>0.05) in the detection results compared with the conventional hydrolysis methods in the industry standard NY/T 939—2016 Identification of reconstituted milk in pasteurized and UHT milk. It can provide technical reference for quality control and heat treatment process evaluation of dairy products.

Objective To establish a magnetic solid phase extraction (MSPE) approach based on covalent organic framework materials in combination with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the efficient determination of 9 kinds of carbamate pesticides (CPs) in Vigna unguiculata. Methods After the extraction of Vigna unguiculata samples, the novel Fe₃O₄@TAPOB-BDTB material was employed for magnetic solid-phase extraction and purification. After filtration, the samples were separated by a C₁₈ chromatographic column and quantitatively analyzed using multiple reaction monitoring in the electrospray positive ion mode. Results The established analytical methods for the 9 kinds of CPs exhibited excellent linearity within the concentration range of 0.02-100.00 μg/kg, with the determination coefficients (r²) all exceeding 0.9989. The spiked recovery rates were within the range of 80.33%-108.63%, and both the intra-day and inter-day precisions were less than 8.89%. The detection limits of the methods were 0.005-0.010 μg/kg, and the limits of quantitation were 0.02 μg/kg, which were significantly below the maximum residue limits specified in GB 2763—2021 National food safety standard-Maximum residue limits of pesticides in food and EU Regulation No 396/2005, ensuring compliance within an academic context. Conclusion The covalent organic framework materials synthesize in this study demonstrate exceptional adsorption capacity for CPs via π-π interactions and hydrogen bonding. Furthermore, the develope MSPE-HPLC-MS/MS method enables rapid, highly sensitive, and precise detection of CPs in Vigna unguiculata, thereby offering an efficient and innovative approach for monitoring pesticide residues in agricultural products.

Objective To establish an analytical method for the simultaneous determination of 6 kinds of fluoroquinolones and 4 kinds of benzodiazepines residues in aquatic products by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Methods Aquatic product samples were extracted with 1% formic acid in acetonitrile. The extracts were concentrated with a rotary evaporator and then reconstituted in 90% acetonitrile aqueous solution (containing 1% formic acid), and purified through a pass-through solid phase extraction cartridge (ProElut PLS-A). The purified extracts were directly analyzed by UPLC-MS/MS. Quantification was performed using the isotope internal standard method. Results The 10 kinds of target compounds exhibited good linearity within the concentration range of 0.5 to 50.0 ng/mL, with correlation coefficients (r) all greater than 0.998. The limits of quantitation for these compounds in 5 kinds of different aquatic product matrices ranged from 0.5 to 1.0 μg/kg. The recovery rates at low, medium and high spiking levels ranged from 81.5% to 109.7%, with relative standard deviations ranging from 0.24% to 13.22%. Conclusion Methodological validation confirmed that the developed method is highly sensitive, accurate in quantification, stable, and straightforward in operation. It is suitable for high-throughput detection of 6 kinds of fluoroquinolones and 4 kinds of benzodiazepines residues in aquatic products.

Objective To establish an analytical method for the determination of enrofloxacin residues in complex mixed matrix of the “soil-vegetable” system by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Methods The sample was subjected to vortex ultrasonic extraction with acidified acetonitrile extract [containing 5% ethylene diamine tetraacetic acid (EDTA)-Mcllvaine buffer solution], settling with centrifugation, getting solvent conversion and being filtered by 0.22 μm nylon filter membrane. The mobile phase was composed of acetonitrile and 0.1% formic acid aqueous solution (containing 2 mmol/L ammonium acetate), and the mixture was subjected to Waters ACQUITY UPLC ® BEH C₁₈ chromatographic column (2.1 mm×100 mm, 1.7 μm) gradient elution separation, using mass spectrometry as a detector for qualitative and quantitative analysis of enrofloxacin. Results In the mass concentration range of 1-200 ng/mL, the standard curve showed a good linear relationship (correlation coefficient=0.9996), the limit of detection of the method was 0.11 μg/kg, the recovery rates ranged from 87.4% to 103.3%, and the relative standard deviations (RSDs) were 0.4% to 4.0% (n=6). Conclusion This method has fast analysis speed, high accuracy and good repeatability, and is suitable for the detection of enrofloxacin residues in complex mixed matrix of the “soil-vegetable” system. It also has the potential to indirectly reveal the risk of antibiotic resistance genes (ARGs) contamination in the system.

N-nitrosamines (NAs) are a class of strongly carcinogenic compounds with high contamination levels in aquatic products, posing significant risks to human health. Recent random inspections in China have revealed that excessive N-nitrosodimethylamine (NDMA) content has become a major factor disqualifying processed aquatic products, seriously hindering the healthy development of the aquatic product processing industry. Therefore, elucidating the formation mechanisms and influencing factors of NAs in aquatic products, along with controlling their levels through processing technologies and multidisciplinary approaches, has become a key research focus. This review systematically examined various formation pathways of NAs in aquatic products, pretreatment methods, and analytical techniques compliant with national food safety standards. It further summarized comprehensive strategies for NAs control, including reduction of NAs precursor intake, blocking of NAs formation pathways, and decomposition of existing NAs. The paper aimed to address the excessive NAs levels in aquatic products, thereby ensuring the quality and safety of aquatic products and promoting sustainable development of the industry.

Objective To prepare edible gelatin-corn starch bio-based composite film loaded with lactive Lactiplantibacillus plantarum CXG9, and endow the film with antibacterial activity and excellent film properties. Methods Using gelatin and corn starch mixed film as substrate, the bacterial mud obtained by Lactiplantibacillus plantarum CXG9 centrifugation was mixed into gelatin-corn starch mixture, and the living bacteria edible composite film was prepared by solution casting method. By measuring the characterization of the film and its antibacterial activity in vitro, the effects of Lactiplantibacillus plantarum CXG9 on the properties of gelatin-corn starch film were studied. Results The elongation at break of the gelatin-corn starch composite film loaded with Lactiplantibacillus plantarum CXG9 increased by 35.51%, the moisture content decreased by 2.55%, and the water vapor permeability also decreased by 11.2%. This indicated that the ultraviolet barrier ability, water vapor permeability, elongation at break, and thermal stability of the film loaded with Lactiplantibacillus plantarum CXG9 had all been improved. On the other hand, the addition of live bacteria gave the film antibacterial properties, and it had different degrees of inhibition on Listeria monocytogenes, Shigella, Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Pseudomonas aeruginosa. Conclusion In this study, gelatin-CXG9-corn starch antibacterial film loaded with Lactiplantibacillus plantarum CXG9 is successfully prepared by using gelatin-corn starch as substrate, which reduces the burden of traditional packaging materials on the environment and opens up a new way for the development of food packaging field.

Objective To establish a method to simultaneously determine the content of 5 kinds of components of Lonicera japonica Thunb. herbs from Sandao real estate area (neochlorogenic acid, chlorogenic acid, isochlorogenic acid A, isochlorogenic acid B and isochlorogenic acid C) by quantitative analysis of multi-components by single marker. Methods Phenomenex Synergi Hydro-RP80A (250 mm×4.6 mm, 4 μm) column was used with acetonitrile (A)-0.1% phosphoric acid aqueous solution (B) as mobile phase, the detection wavelength was 327 nm, the column temperature was 20 ℃, and the flow rate was 0.7 mL/min. The injection volume was 2 µL. Results The linear ranges of neochlorogenic acid, chlorogenic acid, isochlorogenic acid B, isochlorogenic acid A and isochlorogenic acid C were 0.41-16.40, 7.22-289.00, 0.21-8.50, 1.65-66.00 and 0.37-14.80 μg/mL (r≥0.9993), respectively. The average recovery rate was 95.25%-100.42%, and the relative standard deviation (RSD) of precision, repeatability and stability were less than 2.0%. The content of neochlorogenic acid, chlorogenic acid, isochlorogenic acid A, isochlorogenic acid B and isochlorogenic acid C in 25 batches of samples was determined by external standard method, and there was no significant difference between the measured values and the calculated values of quantitative analysis of multi-components by single marker method. Conclusion This method is accurate, reliable and simple for the simultaneous determination of the content of 5 kinds of compounds in Lonicera japonica Thunb., which solves the bottleneck problem of lack of reference substances in the quality control of Lonicera japonica Thunb.. The content of caffeoylquinic acid in Lonicera japonica Thunb. from different origins varies greatly, and it is necessary to further strengthen the processing of Lonicera japonica Thunb.. This study provides an important basis for the identification, quality evaluation and formulation of quality standards of Lonicera japonica Thunb..