Objective To investigate the contamination level of Vibrio parahaemolyticus (VP) in the production chain of the Liuzhou river snails rice noodles, promptly assess the risk of VP in the production chain. Methods From 2023 to 2024, a total of 487 simlpes, including snails and snail meat, semi-finished soup packets, and pre-packed Liuzhou river snails rice noodles final products, were randomly collected from Liuzhou agricultural markets and manufacturing enterprises in Liuzhou. A conbination of culture-based methods and real-time fluorescent polymerase chain reaction (PCR) was used to detect VP. Results Among 70 snails samples from agricultural market with a detection rate of 38.6% and an average contamination level of 16.1 MPN/g in 44 snails samples. In the 41 snails and snail meat sample from manufacturing enterprises showing the detection rate of 2.4%; no VP was detected in the semi-finished soup package or final product. Conclusion Although VP contamination is relatively common in snails at the retail trade, the contamination rate of snails and snail meat in the enterprise is low. Furthermore, the repeated boiling in Liuzhou river snails rice noodles production can effectively control VP. Therefore, the risk of VP contamination in the Liuzhou river snails rice noodles production chain is relatively low.

Objective To detect aflatoxin B₁ (AFB₁) in peanut oil by laser induced fluorescence and explore the effects of temperature on the detection results. Methods The spectral information of AFB₁ contaminated peanut oil at temperatures of 10, 20, 30, 40 and 50 ℃ was collected, linear discriminant analysis (LDA) model was established for qualitative analysis, and partial least squares regression model was established for quantitative analysis. Results The accuracy of the single-temperature LDA detection model in predicting samples at this single temperature exceeded 84%. The global LDA model was lower prediction accuracy than the single-temperature LDA model. The partial least squares regression (PLSR) model could not achieve quantitative prediction at either single temperature or mixed temperature. The PLSR quantitative model developed for single-variety peanut oil demonstrated optimal stability at 20 °C, yielding the most accurate sample predictions. Conclusion This study proposes that a global model can be established during qualitative discriminant analysis to adapt to the impact of temperature on the detection process. In quantitative analysis, the single temperature model can achieve more accurate predictions than the global model.

Objective To evaluate the effects of sub-chronic doses of paralytic shellfish toxins (PSTs) on the livers of mice. Methods In the present study, the effects of different dose concentrations PSTs on hepatic lipid metabolomics were assessed by oral gavage using the lipidomics technique. Results Exposure to the high-and medium-dose group (greater than 100 µg STXeq/kg BW) resulted in abnormal lipid metabolism, with glycerophospholipids (GP) as the major differential lipid metabolites, phosphatidylethanolamine (18:3/22:6) [PE (18:3/22:6)], PE (16:0/18:0), and 16(17)-epoxydocosapentaenoic acid were lower, whereas the relative content of lysophosphatidylethanolamine (P-16:0/0:0) was elevated in relative levels of these lipids, which might serve as biomarkers of liver injury due to PSTs exposure. In contrast, the low dose group (45 µg STXeq/kg BW) did not significantly affect mouse liver lipids. Metabolic pathway enrichment analysis of differential lipids showed that α-linolenic acid metabolism, glyceride metabolism, arachidonic acid metabolism, and steroid hormone biosynthesis were collectively involved in lipid metabolism in the 3 kinds of PSTs experimental groups. Conclusion The effects of PSTs on hepatic lipid metabolism in mice are characterized by a dose-dependent pattern, and lipid dysfunction may affect the neurotoxic effects of PSTs. This study provides a theoretical reference for exploring the mechanism of hepatic injury by PSTs in mice.

Objective To establish an on-site rapid detection system for the risk of deoxynivalenol (DON) contamination based on multienzyme isothermal rapid amplification (MIRA) technology. Methods Highly homologous sequences of Tri toxin-producing gene clusters from the major DON-producing Fusarium species (including Fusarium graminearum, Fusarium asiaticum, Fusarium pseudograminearum and Fusarium culmorum) in China were obtained through gene sequence query and comparison by the National Centre for Biotechnology Information (NCBI) of the United States of America. By designing specific fluorescent probes and screening primers, a MIRA detection method for DON-producing Fusarium was established, and an on-site rapid detection system was constructed by combining the rapid paper-based DNA extraction technique. Results The limit of detection of this assay system was 1.95×10¹ copies/μL for plasmid templates and 15 fg/μL for genomic DNA. The results of 27 positive wheat samples at the filling stage (spike) showed a highly significant correlation with those of the quantitative real-time polymerase chain reaction (qPCR) method (r=0.820, P=0.000). When the MIRA detection threshold line was set at the 43rd scan point (peak onset time of 7 min), the combined discrimination accuracy between high (DON>1000 μg/kg) and low (DON<1000 μg/kg) DON contamination risk for 89 wheat samples was 87.15%. Conclusion The detection system demonstrates speed, economy, practicality, and portability in terms of reagents and instrumentation, and is capable of effectively achieving the objective of rapid on-site detection. This will facilitate early warning of the risk of DON contamination in wheat production in the field, thereby guiding interventions to prevent or minimise losses.

Objective To explore a method that can monitor the immunoaffinity column capacity of zearalenone (ZEN) in real time during detection. Methods The 2 kinds of artificial structural analogues of ZEN (α-ZEL-G and β-ZEL-G) were synthesized by esterification of α-zearalanol (α-ZEL) and β-zearalanol (β-ZEL) with glutaric anhydride in this study. The products were purified and identified by fluorescence, ultraviolet and high-resolution mass spectrometry. A competitive enzyme-linked immunosorbent assay (ELISA) curve was established using the same antibody with immunoaffinity columns, and their affinity with the antibody was compared by half maximal inhibitory concentration (IC₅₀). α-ZEL-G and β-ZEL-G were used as column capacity tracers and added to the immunoaffinity column together with different concentrations of ZEN to explore a method for real-time monitoring of immunoaffinity column capacity. Results The IC₅₀ of the competitive ELISA curves of ZEN, α-ZEL-G and β-ZEL-G were 2.0, 1.3 and 10.0 ng/mL, respectively, indicating that the affinity of α-ZEL-G with antibody was slightly higher than that of ZEN, while the affinity of β-ZEL-G with antibody was significantly lower than that of ZEN with antibody. The experimental results showed that: α-ZEL-G in immunoaffinity columns with different column sizes would affect the recovery rates of ZEN. Whereas the recovery rates of ZEN with different concentration were more than 80% while the adding concentrations of β-ZEL-G was 50% of the column capacity. Conclusion β-ZEL-G with lower antibody affinity is more suitable for real-time monitoring of column volume. It shows good application results in the test of actual samples.

Objective To study and analyze the mycotoxins contamination status of Castanea mollissima in Huairou District during one year of cold storage. Methods Taking Castanea mollissima produced in Huairou District as the research object. Castanea mollissima samples of 5 varieties, including 3113, Huaijiu, Huaihuang, Yanhong, and Huahua were collected from the 4 highest yielding townships in Huairou District. They were stored in a cold storage for one year and sampled once a month. The content of 21 kinds of fungal toxins was determined by ultra performance liquid chromatography-mass spectrometry. Results During the storage period, a total of 11 fungal toxins were detected, including tentoxin, alternariol, tenuazonic acid, nivalenol, zearalenone, fumonisin B₁, fumonisin B₂, fumonisin B₃, alternariolmethylether, ochratoxin A, and sterigmatocystin. The detection rate and value of Alternaria toxins were relatively high. According to the analysis of sampling locations, the number of fungal toxins detected in the 4 townships increased from 66 to 79, with no significant difference or clear pattern. Based on the analysis of storage time, the number of fungal toxins detected in chestnuts showed an overall upward trend with the extension of storage time. The detection rate of fungal toxins was relatively low in the 1 to 6 months of storage, with 4-5 cases detected each month. By the 7th month, the detection of fungal toxins increased to 12 cases, and from the 9th month onwards, all 17 samples were detected. Conclusion The Castanea mollissima shall be consumed and processed less than 6 months of storage after harvest according to the perspective of mycotoxins contamination. The overall detection rate of fungal toxins shows a monthly upward trend. There is no regularity in the detection of fungal toxins in different chestnut planting areas and varieties, and there is co-contamination in Castanea mollissima samples during storage. Further analysis and research on the pollution risk of Alternaria toxins in chestnuts is needed.

Objective To analyze the contamination levels of deoxynivalenol (DON) in Triticum, Zea mays and their processed products in the Dalian Region and assess the acute and chronic dietary exposures of DON to the consuming population. Methods From 2019 to 2023, 287 samples of Triticum, Zea mays and their processed products were collected from Dalian. DON levels were determined using liquid chromatography-tandem mass spectrometry. Combined with the 2018 Dalian City dietary consumption survey data, acute and chronic dietary exposures of DON were assessed in different age groups using point estimation and simple distribution methods. Results DON was detected in 77.0% of the Triticum, Zea mays and their processed products, with a 3.5% over-standard rate. The average DON level was 263.62 µg/kg. Acute exposure assessment indicated that DON exposure levels in all age groups did not exceed the acute reference dose. Chronic exposure assessment revealed that 3.85%, 7.30%, 1.44%, and 0.12% of consuming populations in the 3-5, 6-10, 11-17 and 18-64 age groups, exceeded the provisional maximum tolerable daily intake, respectively. Triticum and its products were the primary dietary sources of DON exposure for all age groups. Conclusion DON contamination is prevalent in Triticum, Zea mays and their products in Dalian City. Acute dietary exposure of DON does not exceed the threshold values. However, chronic exposure risks are shown in low age groups. Enhanced monitoring of DON contamination in Triticum, Zea mays and their processed products is recommended, along with a focus on the health risks for high-risk populations.

Objective To prepare a high-titer monoclonal antibody detection kit for aflatoxin B₁ (AFB₁) and rapidly and accurately detect AFB₁ in food. Methods By carbodiimide method, AFB₁ was conjugated with bovine albumin (BSA) to form immune antigen, and with chicken ovalbumin (OVA) to prepare detection antigen. AFB₁ monoclonal antibody was prepared by immunizing mice, cell fusion, screening of hybridoma cells, inducing ascites in vivo, isolation and purification, and a kit for rapid detection of AFB₁ was developed. Results The prepared monoclonal antibody had a titer of up to 1:27 w and showed weak cross-reactivity to Shentuqumycin, with a reaction rate of 13%. No cross-reactivity was observed with the other 2 compounds. The relative standard deviation of the intra- and inter-batch tests for the spiked samples was 2.6%-3.6% and 5.0%-8.0%, respectively. The recoveries were 89.82%-103.64%. The detection sensitivity (median inhibitory concentration value) was 650 pg/mL, with a detection range of 156-5000 pg/mL with the limit of detection of 100 pg/mL. When AFB₁ content was detected in corn flour from different origins, the detection results were 9.756, 2.483, 3.995, 39.080 and 7.831 μg/kg. Conclusion This research has prepared high-titer monoclonal antibodies against AFB₁. These antibodies can not only be utilized for the development of test kit detection experimental methods but also lay the foundation for the development of rapid test strips based on AFB₁ monoclonal antibodies and the colloidal gold method.

Objective To establish a method for the determination of 8 kinds of fungal toxins in rice noodles with liquid-liquid dispersion extraction and multifunctional purification by high performance liquid chromatography-tandem mass spectrometry. Methods Rice noodle samples were added with isotopic internal standards, and extracted by shaking with acetonitrile water (80:20, V:V) for 25 min. After liquid-liquid dispersion extraction, a multifunctional purification column was used for purification. The 8 kinds of target compounds were separated on HSS T3 column, with acetonitrile-water (0.1% formic acid) used as the mobile phase for gradient elution, and detected under positive and negative ionization and multiple reaction monitoring mode, determined with retention time and characteristic ion pairs, quantified with internal standard method. Results This method had a good linear relationship in detecting 8 kinds of fungal toxins within the corresponding range. The correlation coefficients (r) of the target compounds were 0.9954-0.9998. The limits of detection were 0.10-10.00 μg/kg, and the limits of quantification were 0.30-30.00 μg/kg. The average recoveries of rice noodle samples at low, middle and high standard additions were 75.8%-112.0%, and the relative standard deviations were 2.9%-5.9%. The detection and analysis of 8 kinds of fungal toxins in 21 kinds of rice noodle samples in the market showed that all the toxins were detected except HT-2. Conclusion The pretreatment of sample is simple, the method is accurate and sensitive, which can be used to determine the content of 8 kinds of fungal toxins in rice noodles.

Objective To investigate and analyze the contamination of 8 kinds of mycotoxins in commercial popcorn from Hunan Province of China in 2024, and assess the associated health risks. Methods A total of 67 popcorn samples were collected from 14 cities and states in 2024 from Hunan Provinces of China, the content of aflatoxin B₁, B₂, G₁, G₂, fumonisins B₁, B₂, B₃, and zearalenone (ZEN) was determined by isotope dilution ultra performance liquid chromatography-tandem mass spectrometry, the risk assessment was evaluated by the Nemerow comprehensive pollution index method, risk assessment of chronic dietary exposure and carcinogenic risk assessment. Results In the 67 tested popcorn samples, the detection rate of fumonisins B₁ was 46.27%, with a maximum value of 285.0 μg/kg, fumonisins B₂ was detected in 5 samples, with a maximum value of 80.0 μg/kg, ZEN was detected in 10 samples, with a maximum value of 47.7 μg/kg, and no detection of 4 kinds of aflatoxin and fumonisins B₃ were found. The detection rate of fumonisins B₁ in loose packaging samples was slightly higher than that in packaged products, but there was no statistically significant difference (P>0.05); the level of fungal toxin contamination in popcorn across the 14 prefecture-level cities in the province posed no obvious risk to human health. Conclusion Mycotoxin contamination is common in the popcorn sold in Hunan Province, and fumonitoxin B₁ is the main pollution toxin, and there is a co-pollution phenomenon with fumonitoxin B₂ or ZEN. In view of fumonitoxin pollution, it is recommended to pay close attention to the problem, timely traceability investigation, and take corresponding measures.