To understand the contamination status of Listeria monocytogenes in meat and meat products in Jiangsu Province.

From 2015 to 2024, a total of 5705 different types of meat and meat products were collected from multiple links including agricultural product markets, supermarkets and restaurants in 13 prefecture-level cities in Jiangsu Province to detect Listeria monocytogenes according to the protocol of National food contamination and hazardous factors risk monitoring. The results were statistically analyzed by SPSS 27.0 software.

Among the 5705 samples, 328 were tested positive for Listeria monocytogenes, with an overall detection rate of 5.7%. The detection rate of raw meat and its products was significantly higher than that of cooked meat and its products (χ²=91.717, P<0.001). There were significant differences in the detection rates among pork,beef, chicken and duck samples (χ²=11.510, P=0.009). Besides, there were significant differences in the detection rates among fresh meat, chilled meat and frozen meat samples (χ²=89.652, P<0.001). The detection rate of samples from the circulation link was significantly higher than that of the catering link (χ²=10.388, P=0.001). There were significant differences in the detection rate of Listeria monocytogenes among samples collected from agricultural product markets, supermarkets, and online stores (χ²=6.038, P=0.049).

Contamination with Listeria monocytogenes continues to exist in meat and meat products in different regions of Jiangsu Province, which has potential risks. Surveillance and regulation should be enhanced to prevent the occurrence of related foodborne diseases.

To investigate the transformation rule of flavonoids in Abelmoschus esculentus (L.)Moench seeds induced by roasting and its impact on antioxidant activity, elucidate the underlying material basis and mechanism of action.

The antioxidant activity of Abelmoschus esculentus (L.) Moench seeds before and after roasting was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, expressed as the half-maximal inhibitory concentration (IC₅₀). The total flavonoid content was determined by ultraviolet-visible spectrophotometry. The content changes of 3 kinds of key flavonoid compounds—quercetin-3-O-gentiobioside,isoquercitrin and quercetin—were quantitatively analyzed using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Compared with unroasted samples, roasted Abelmoschus esculentus(L.) Moench seeds exhibited significant component transformation and enhanced activity: The DPPH radical scavenging capacity was substantially increased, with the IC₅₀ value significantly decreased, indicating approximately 9-fold higher activity than the raw product (P<0.01). The total flavonoid average content was significantly increased by 346.3% (P<0.01). Component analysis revealed that the content of quercetin-3-O-gentiobioside and isoquercitrin decreased by 39.1% (P<0.01) and 48.9% (P<0.01), respectively, while the quercetin content significantly increased by 60.0% (P<0.01).

Roasting can induce the cleavage of glycosidic bonds in quercetin glycosides (quercetin-3-O-gentiobioside and isoquercitrin) in Abelmoschus esculentus(L.) Moench seeds, directing their conversion into the aglycone form—quercetin. This structural transformation leads to the exposure of free hydroxyl groups with stronger free radical scavenging capacity, which is the primary material basis and key mechanism for the significant enhancement of the antioxidant activity in Abelmoschus esculentus (L.)Moench seeds. This discovery provides a theoretical foundation for the deep processing and development of functional products from Abelmoschus esculentus (L.) Moench seeds.

To evaluate the contamination levels of Bacillus cereus and Burkholderia gladioli pathovar cocovenenans (BGC), along with the moisture content and dehydroacetic acid levels in wet rice and flour products in Yunnan Province.

From July to December 2024, a total of 108 samples of bulk wet rice products (including 48 portions of vermicelli, 47 portions of rice noodles, etc.) were collected from prefectures in Yunnan Province, covering markets (50.93%), supermarkets (17.59%), small restaurants (12.96%) and other locations. Pathogens were detected in accordance with GB 4789.14—2014 National food safety standard food-Microbiological examination-Detection of Bacillus cereus and GB 4789.29—2020 National food safety standard food-Microbiological examination-Detection of Burkholderia gladioli (formerly Pseudomonas cocovenenans subsp. Farinofermentans), while moisture and dehydroacetic acid content were determined in accordance with GB 5009.3—2016 National food safety standard-Determination of moisture in food and GB 5009.121—2016 National food safety standard-Determination of dehydroacetic acid in food.

The detection rate of Bacillus cereus was 31.48% (34/108), with a quantitative range of <10–6.8×10⁴ CFU/g (P₉₀=4140 CFU/g). The highest detection rate was observed in roll noodles (43.75%,P=0.022), and the detection rate in refrigerated samples (45.71%) was significantly higher than that in the room temperature group (P<0.001). Neither BGC nor excessive dehydroacetic acid was detected in any of the samples. The 3 samples of wet rice noodle products failed to meet the moisture content requirements stipulated in DBS53/017—2023 Local food safety standards of Yunnan Province-Rice noodles, rolled rice noodles and rice vermicelli (blocks).

Wet rice products in Yunnan are at risk of contamination by Bacillus cereus, particularly roll noodles and refrigerated products. It is essential to strengthen hygiene control in both production and circulation processes. No BGC contamination or potential risk of food poisoning caused by rice-fermenting bacteria has been identified.

To establish a method to detect fluoride content based on the fluoride riboswitch transcription system and clustered regularly interspaced short palindromic repeats-associated protein 12a(CRISPR/Cas12a).

The system utilized fluoride riboswitch to regulate transcription of full-length or truncated RNA in the presence/absence of fluoride, which was then detected by CRISPR/Cas12a-mediated fluorescence signal. Selectivity and interference analyses were conducted to optimize CRISPR/Cas12a detection system, and the method was applied to measure fluoride content in Euphausia superba.

This study successfully established a fluorescence detection method based on a fluoride riboswitch transcription reaction system and CRISPR/Cas12a, which completed sample detection within 1.5 h with the results consistent with those obtained by the national standard fluoride ion-selective electrode method.

The fluoride detection method established in this study for Euphausia superba based on a fluoride riboswitch transcription reaction system and CRISPR/Cas12a, demonstrates high specificity and accuracy, showing potential for fluoride content analysis.

To establish a method for determination the content of functional components of various medicinal and edible homology (glycyrrhizic acid, kaempferol-3-O-rutinoside, isoflavan glucoside,luteolin-7-glucoside, puerarin, chlorogenic acid, salidroside and glycyrrhizin) in botanical beverages by ultra-high pressure liquid chromatography.

The appropriate amount of botanical beverage sample was weighed, the sample was vortex-dispersed with a methanol-water solution and then performed ultrasound-assisted extraction to fully release the target dispersed components. After centrifugation, the supernatant was collected. An EC-C₁₈ chromatographic column was used for the separation of various components in the extract, and quantitative analysis was performed using the external standard method., the content of 8 kinds of efficacy components in the botanical beverage was simultaneously detected.

The 8 kinds of active components exhibited good linearity within the mass concentration range of 0.50–25.00 mg/L, with correlation coefficients (r)>0.998. The limits of detection and limits of quantitation for the 8 kinds of functional components ranged from 0.05 to 0.50 mg/kg and 0.16 to 1.50 mg/kg,respectively. The recovery rates were between 83.2% and 96.1% and the relative standard deviations of the test results were 3.2%–6.2% (n=3).

The established method demonstrates excellent precision and recovery rates,along with satisfactory sensitivity, making it suitable for determining the content of these 8 kinds of pharmacologically active components in botanical beverages.

To analyse of foodborne pathogen contamination in edible fungi sold in Chongqing from 2022 to 2024.

A total of 700 samples of wood ear and tremella were collected in 2022—2024 and tested for Listeria monocytogenes, Salmonella and Burkholderia gladioli according to the requirements of the national food safety standards.

A total of 112 positive samples were detected among 700 samples, with a detection rate of 16.00%. The detection rates of Listeria monocytogenes, Burkholderia gladioli and Salmonella were 7.14% (50/700), 6.86% (48/700) and 3.14% (22/700), respectively. The detection rates of pathogenic bacteria in rehydrated and fresh edible fungi were 20.00% (19/95) and 18.69% (94/503), respectively, which were significantly higher than that in dried edible fungi (6.86%, 7/102). The detection rate of foodborne pathogens in bulk edible fungi (including self-made simple packaging) was 18.41% (118/641), which was higher than that in pre-packaged products (3.39%, 2/59). Among the different sampling locations, the detection rate of farmers’ market was the highest at 22.84%(82/359), and the lowest at 2.27% (1/44) in online shops.

The edible fungi sold in Chongqing are more seriously contaminated by Listeria monocytogenes and Burkholderia gladioli, with rehydrated and fresh edible fungi posing a particularly higher risk of foodborne diseases. The degree of pathogenic contamination of edible fungi is related to the type of packaging and the distribution link. In this regard, it is recommended to strengthen the supervision of the whole chain of production, circulation and sales, form a closed-loop disposal of the whole process of traceability, and carry out science popularization activities through multiple channels to enhance the public risk awareness and protect consumer health.

To establish a method for the determination of sec-butylamine residues in fruits and vegetables by gas chromatographic.

The sample was shaken in acidic solution, capped and heated at 60 ℃for 40 min. The sec-butylamine in the sample would diffuse into the gas phase in the closed container’s acidic solution. The content of sec-butylamine in the upper gas phase was determined by gas chromatography, and quantified by external standard method.

Sec-butylamine showed good linearity in the range of 0.1–2.0 mg/L, and the correlation coefficient (r²) was over 0.99. The limit of detection and limit of quantitation were 0.05 mg/kg and 0.1 mg/kg, respectively. Recoveries ranged from 84.1% to 91.8% with relative standard deviations less than 15%.

This method is simple to operate, has a fast analysis speed, high sensitivity, good repeatability and accurate results. It can be used for the determination of isobutylamine residues in fruits and vegetables.

To establish an efficient and accurate analytical method to track the transfer and distribution patterns of pesticide residues from brewing raw materials to the final Baijiu products, and to assess their potential risks.

Raw materials (rice and glutinous rice) from different sources and their corresponding Baijiu products were collected. Samples were extracted and purified with acetonitrile, then analyzed using ultra performance liquid chromatography-Orbitrap-high resolution mass spectrometry. Compounds were identified through a pseudo-targeted screening approach with database matching and quantified using reference standards.

The established quantitative analytical methods for 5 kinds of pesticide residues, including triazophos,alloxydim, isoprothiolane, bufencarb and pebulate, exhibited good linearity in the range of 1.0–50.0 ng/mL(correlation coefficient, r>0.998). The method limits of detection and limits of quantitation were 0.12–0.32 ng/mL and 0.48–1.05 ng/mL, respectively. The spiked recoveries ranged from 88.60% to 95.60% with relative standard deviations below 3%. Analysis of distribution characteristics revealed that pesticide residues were primarily concentrated in raw materials from scattered household farming. Triazophos, alloxydim and isoprothiolane were commonly detected in both rice and glutinous rice samples, whereas butacarb (detected in both rice and glutinous rice) and pebulate (detected only in glutinous rice) were specifically found in samples collected after October 30,indicating significant spatio-temporal distribution differences. No high-risk pesticide residues were detected in raw materials from base cultivation or in any Baijiu products. The risk assessment indicated that the levels of all detected pesticide residues were below the GB 2763—2021 National food safety standards-Maximum residue limits of pesticides in food, suggesting that the overall risk is controllable.

This study successfully reveals the key distribution nodes and characteristics of pesticide residues throughout the Baijiu production chain, identifying that the risk primarily originates from raw materials of specific sources and procurement batches. It provides crucial data support and a scientific basis for implementing targeted source control and whole-process risk early warning in the Baijiu industry.