Objective To understand the metal element contamination in liquid milk in Inner Mongolia region from 2022 to 2023 and assess the metal health exposure risk for the population in Inner Mongolia region. Methods A total of 4103 samples of locally produced liquid milk were collected from Inner Mongolia region. Lead, total mercury, cadmium, chromium and total arsenic were detected using inductively coupled plasma mass spectrometry. The inverno comprehensive pollution index method was used to evaluate the pollution levels of these elements. Considering the actual dietary intake of residents in Inner Mongolia region, the carcinogenic risk assessment (TCR) and non-carcinogenic risk assessment [target hazard quotient (THQ)] were employed to assess the health risks posed by metal elements in liquid milk to the population in Inner Mongolia region. Results In the 4013 samples monitored, all 5 kinds of metal elements were detected. The over-limit detection rate for lead was 22.26% (187/840), for cadmium it was 5.83% (49/840), for total mercury it was 5.12% (43/840), for total arsenic it was 6.54% (55/841), and for chromium it was 40.18% (262/652). Lead, total mercury, and total arsenic all had samples exceeding the limits, with exceedance rates of 5.83% (49/840), 0.119% (1/841), and 0.12% (1/841), respectively. The inverno index for all 5 kinds of metal elements was below 0.7; the TCR for total arsenic and cadmium was less than 10^-4, Within an acceptable risk range; THQ of lead, chromium, and total mercury were all less than 1. Conclusion This study systematically analyzed and comprehensively assessed the sources of heavy metal pollution in liquid milk from different production and processing types, providing a scientific basis for government decision-making, regulation, and the revision of national food safety standards.

Objective To investigate the effects of low-temperature fermentation processes and fermentation duration on the aroma composition and aromatic characteristics of summer-harvested Jingshan black tea. Methods First, headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with sensory evaluation was used to analyze the aroma components of 12 samples fermented at 3 temperatures (25, 28 and 35 ℃) and four durations (2.5, 4.0, 5.5 and 7.0 h). Second, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were employed to explore the differences among samples under varying fermentation conditions (temperature and duration). Finally, Orthogonal partial least squares-discriminant analysis (OPLS-DA) with variable importance projection (VIP) scores and relative odorant activity value (OAV) was conducted to screen differential volatile compounds related to fermentation conditions. Results A total of 86 kinds of aroma components were analyzed and identified by the above-mentioned methods. Among them, 15 kinds of substances, such as dimethyl sulfide, linalool, (E,E)-2,4-heptadienal, indole and geraniol, were identified as the key differential volatile compounds under different fermentation conditions (temperature and time). Compared with other fermentation time samples, 4.0 h samples had higher concentration of volatile compounds and better quality. Among the samples with a 4.0 h fermentation duration, the samples fermented at 25 ℃ and 28 ℃ obtained higher sensory scores and presented distinct aroma profiles. At this duration, 25 ℃ and 4.0 h-fermented samples displayed floral aromas dominated by dimethyl sulfide, dehydro-linalool, linalool and neral, while 28 ℃ and 4.0 h-fermented samples exhibited fruity notes characterized by myrcene, citral and geraniol. Conclusion Low-temperature fermentation processes and fermentation duration critically influence the aromatic quality of Jingshan black tea.

Objective To construct and compare the fingerprint profiles of Astragalus samples from different origins based on ultra performance liquid chromatography-charged aerosol detector (UPLC-CAD) technology, achieve quality evaluation and origin identification of Astragalus. Methods Using UPLC-CAD technology, this study focused on flavonoid and saponin components to construct the fingerprint of wild-simulated Astragalus membranaceus from the Hengshan Mountains, based on 29 batches of samples collected from multiple geographical origins. Statistical analysis methods such as cluster analysis, principal component analysis (PCA), and orthogonal partial least squares discriminant analysis (OPLS-DA) were used for analysis and evaluation. Results The fingerprint successfully marked 26 common peaks, and 8 key characteristic peaks were identified, including complanatoside A, ononin, astragaloside I to IV, etc. Cluster analysis clearly divided the samples into two major categories, revealing the influence of regional differences on the quality of Astragalus membranaceus. PCA further extracted 7 principal components. OPLS-DA analysis accurately predicted 8 kinds of key compounds influencing the quality differences, which were closely related to origin, cultivation methods, and growth duration. Conclusion This study successfully constructed a fingerprint capable of distinguishing Astragalus based on its origin, cultivation methods, and growth conditions by integrating UPLC-CAD technology with multivariate chemometric analysis. This method can be used to evaluate the fingerprint similarity of Astragalus membranaceus (Hengshan Mountain wild-simulated), with high specificity and sensitivity, which provids a scientific basis for the quality assessment of wild-simulated Astragalus from the Hengshan Mountains.

Objective To understand the effect of sodium diacetate on the growth and toxin production of Burkholderia gladioli in fresh wet rice noodles medium. Methods A total of 10 Burkholderia gladioli strains isolated from wet rice noodles samples and rice raw materials and purchased by the strain preservation center were used as research objects. The strains were inoculated into the medium supplemented with different proportions of sodium diacetate to study the growth and toxin production of the strains in the medium. Results The growth of 10 strains of Burkholderia gladioli in BHI broth was consistent. Sodium diacetate had consistent inhibitory effects on different bacterial strains. When the addition of sodium diacetate in BHI broth was more than 0.1%, the growth of 10 strains of Burkholderia gladioli was significantly inhibited, and there was no bacterial growth when the addition reached 0.2%. In BHI semi-solid medium and wet rice noodles medium, when sodium diacetate was added more than 0.1%, the growth of Burkholderia gladioli was significantly weakened or even completely inhibited, and the production of bongkrekic acid was also greatly reduced. Conclusions Sodium diacetate can effectively inhibit the growth of Burkholderia gladioli and reduce the production of bongkrekic acid. It is expected to become a safe and effective preservative or compound preservative that can act on Burkholderia gladioli, reducing the risk of contamination by Burkholderia gladioli at a more affordable cost in the industry.

Objective To deeply analyze the sensory quality of flavor during the ripening process of red cheese through various methods for measuring food flavor quality. Methods The volatile flavor compounds and sensory quality of red cheese at different ripening periods were analyzed by solid phase microextraction arrow-gas chromatography-mass spectrometry (SPME arrow-GC-MS), electronic nose, electronic tongue, and quantitative descriptive analysis (QDA). Results The results showed that there were differences in the flavor profiles of red cheeses at different ripening periods. A total of 85 kinds of volatile flavor compounds were identified in red cheese by GC-MS. The total content of acids, alcohols, aldehydes, and ketones first increased and then decreased, while the total content of esters continued to increase. Combined with the relative odor activity value (ROAV) analysis, 28 kinds of characteristic volatile flavor compounds were identified. QDA yielded that yogurt flavor, wine flavor, and sour flavor would enhance significantly (P<0.05) during cheese ripening. In addition, electronic tongue analysis demonstrated significant differences in sourness and bitter aftertaste among red cheeses at different ripening periods (P<0.05). Conclusion This study analyzes and compares the sensory quality of flavor during the ripening process of red cheese from multiple perspectives by combining various methods for measuring food flavor quality. This study not only improves the understanding of the sensory qualities of red cheese but also provides a reference for the development, quality control, and flavor improvement of novel fermented dairy products.

Objective To investigate the effects of Bacillus natto fermentation on the quality characteristics and storage stability of Arachis hypogaea L. natto produced from red Arachis hypogaea L.. Methods A novel Arachis hypogaea L. product, Arachis hypogaea L. natto, was prepared through fermentation using Bacillus natto, and its quality characteristics and storage stability were systematically evaluated. In this study, the protein content, fat content and flavor compounds of Arachis hypogaea L. natto were determined. Sensory scores and L^* were monitored during the storage period. Additionally, the levels of total volatile basic nitrogen (TVB-N), amino acid nitrogen and a^* were assessed. Results The results indicated that compared with unfermented Arachis hypogaea L., the protein content of Arachis hypogaea L. natto decreased to 25.84%, and the fat content reduced to 17.72%. Fermentation promoted the production of alcohol and aromatic compounds, resulting in distinct flavor profiles characterized by sourness, saltiness, umami and bitterness. During fermentation, lipolysis produced linoleic acid, leading to a reduction in fat content. Moreover, some free water became less mobile, transitioning into weakly bound water. Over time, the sensory score and L^* and b^* of Arachis hypogaea L. natto declined, whereas the levels of TVB-N, amino acid nitrogen increased. Conclusion Bacillus natto fermentation significantly alters the nutritional composition and flavor characteristics of Arachis hypogaea L. natto. sensory quality deteriorates during storage. These findings provide a theoretical foundation for utilizing Bacillus natto in Arachis hypogaea L. fermentation and offer new insights into developing innovative Arachis hypogaea L. products.

Objective To investigate the content of tea polyphenols, catechins, and caffeine in novel-tea beverages available on the market. Methods This study collected and analyzed total of 46 samples from 17 different brands in the market. These products were categorized and compared into 3 types: Novel-milk tea beverages, novel-blended tea beverages and novel-pure tea beverages. Results The findings revealed that the average volume of these was 566 mL per cup. Comparison of average prices of 3 different kinds of new tea drinks was as follows: Novel-milk tea beverages>novel-blended tea beverages>novel-pure tea beverages. In terms of chemical composition, the content of tea polyphenols, catechins, and caffeine in novel-milk tea beverages were significantly lower compared to those in novel-blended tea beverages and novel-pure tea beverages. Notably, the content of tea polyphenols and catechins were influenced by the type of tea base used in the novel-tea beverages. In this study, green tea bases were characterized by tea polyphenols content exceeding 1000 mg/kg and catechins content exceeding 400 mg/kg. Conclusion This research can enable consumers to understand the specifications, prices and tea component content of novel-tea beverages on the market, and also provide assistance for product research and development of novel-tea beverages.

Objective To establish a visual detection method of Salmonella based on recombinant enzyme polymerase amplification-CRISPR/Cas12a. Methods In this study, recombinase polymerase amplification (PRA) was combined with clustered regularly interspaced short palindromic repeats/associated protein 12a (CRISPR/Cas12a) system. RPA primers and CRISPR-derived RNA (crRNA) were designed and synthesized based on the target invA gene of Salmonella. Fluorescence and test strip methods were employed to read the results. The optimized RPA-CRISPR/Cas12 detection system were evaluated for specificity and sensitivity, and was applied to the detection of food samples. Results Nano gold test strip base on nucleic acid were developed. The established RPA-CRISPR/Cas12 detection method could specifically detecting Salmonella with a sensitivity of 80 CFU/mL within 1.5 h. Used this method to detect 21 kinds of food samples, the results from fluorescence and test strip read were consistent, with a Salmonella detection rate of 4.8%, which was completely consistent with the results of the national standard method. Conclusion The Salmonella RPA-CRISPR/Cas12a visual detection method established in this study has high specificity and sensitivity and is valuable for on-site rapid detection of Salmonella.

Objective To conducte compression tests and finite element mechanical simulations on Eriobotrya japonica (Thunb.) Lindl., and investigate its compression characteristics. Methods The compression deformation process of Eriobotrya japonica (Thunb.) Lindl. was repeatedly tested by universal electronic material testing machine, and the relationship curve between compression force and deformation was obtained. The feature points and feature chains of fruits pictures were extracted by image processing, and the 3D digital model of fruits was constructed. The stress and strain distribution of its fruits under compression was analyzed based on ANSYS Workbench 2024 R1 finite element simulation software. Results The yield load of Eriobotrya japonica (Thunb.) Lindl. fruit was 38.25 N. The average relative error between the finite element simulation model and compression test was 5.93%, which proved that the compression test of its fruit was reasonable and effective. The stress-strain cloud map of fruit compression test was obtained. It was found that the maximum stress position of Eriobotrya japonica (Thunb.) Lindl. was at the edge of the contact between the fruit and the upper pressure plate, the maximum stress value was 0.14057 MPa and the maximum strain value was 0.52233 mm. Conclusion In the process of picking and circulation of Eriobotrya japonica (Thunb.) Lindl., it shall be noted that the extrusion pressure generated by mechanical picking and fruit stacking shall not exceed 38.25 N to avoid mechanical compression damage. At the same time, it is necessary to do a good job of packaging buffering to protect the maximum stress part of its fruits.

Objective To understand the contamination distribution and drug resistance of Enterobacteriaceae bacteria in 3 types of food in Handan Area, and to build a contamination database of foodborne Enterobacteriaceae. Methods Food and drug substances, food for special diet, nuts and seeds and their processed products were collected in Handan City from 2023 to 2024. Enterobacteriaceae were isolated and identified by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry, and quantitative count and drug sensitivity test of Enterobacteriaceae were performed. Results Among 196 food samples, 22 samples were positive for Enterobacteriaceae, positive rate 11.2%. The detection rate of Enterobacteriaceae in bulk food was 20.0% higher than 6.3% in pre-packaged food, and the difference was statistically significant (χ²=8.415, P<0.05). The total contamination of Enterobacteriaceae ranged from 1.00-4.67 lg CFU/g. The 31 strains of Enterobacteriaceae were identified in 22 positive foods, including 17 kinds of bacteria from 9 genera. In the drug susceptibility test of 15 kinds of antibiotics, 32.26% of Enterobacteriaceae bacteria were drug-resistant strains, and the resistance rates of ampicillin (25.81%) and ceftazidime (12.90%) were relatively high, while the resistance rates of chloramphenicol,compound sulfamethoxazole tablets, colistin, cefotaxime, ampicillin/sulbactam and tetracycline were relatively low (all resistance rates≤10.00%). The sensitivity to ertapenem, meropenem, ceftazidime/avibactam, tigacycline, ciprofloxacin, nalidixic acid and amikacin was 100.00%. One strain of Leclercia adecarboxylata was detected in bulk jujube, which was resistant to the most types of antibiotics. Conclusion There is a certain degree of Enterobacteriae bacteria contamination in food in Handan Area, and the contamination rate of bulk food is significantly higher than that of pre-packaged food. A wide variety of Enterobacteriae bacteria are detected, and the drug resistance of different bacteria is significantly different. Targeted monitoring should be further strengthened to prevent and control foodborne diseases.