Nuts, being nutritionally rich, are widely favored by the public as healthy snacks. Nevertheless, the issue of mycotoxin contamination presents a potential hazard to their safety for consumption. During the processes of nut cultivation, harvesting and storage, nuts can become contaminated by fungi and produce toxins. These fungal toxins have the ability to accumulate in the human body. Prolonged consumption of contaminated nuts can cause harm to vital organs such as the liver and kidneys, thereby elevating the risk of cancer and neurological disorders. This article conducts a systematic analysis of the types and ecological distribution characteristics of mycotoxigenic fungi within the nut supply-chain. Moreover, it placed emphasis on reviewing the latest advancements in the current mycotoxin detection technology systems. These included well-established methods like mass spectrometry, chromatography, chemiluminescence and fluorescence, as well as modern toxin detection technologies and their recent breakthroughs. On this basis, the article also explored the future development trajectory of toxin detection technology. The ultimate goal is to offer a reliable guarantee for the stable development of the nut industry.

Objective To understand the residual levels of semicarbazide in crustacean aquatic products such as shrimp and crabs, analyze the causes of endogenous and exogenous contamination. Methods Data from nationwide sampling inspections of crustacean aquatic products from 2017 to 2023 were analyzed. A total of 178 batches of shrimp, 136 batches of crabs, and aquaculture pond water samples were collected and tested. The quantitative determination was conducted following the standard of Ministry of Agriculture Announcement No.783-1-2006 Determination of nitrofuran metabolite residues in aquatic products. Results The detection level of semicarbazide in crabs was significantly lower than that in shrimp. The semicarbazide levels in crabs showed little correlation with species, while significant variations were observed among different shrimp species. No semicarbazide residues were detected in aquaculture pond water. Conclusion The presence of semicarbazide in crustacean aquatic products such as shrimp and crabs is primarily related to endogenous sources, though the detected levels from endogenous origins are very low. It is recommended that national authorities resume routine supervision and sampling inspections for nitrofurazone metabolites in crustacean products, establish a national database for semicarbazide monitoring, and utilize big data analysis to address current policy gaps. Furthermore, based on the analysis of the national database, efforts should be made to develop semicarbazide residue limit standards for crustacean aquatic products to ensure the healthy development of the aquaculture industry.

Objective To construct a predictive model for bacterial growth in braised chicken legs under variable temperature conditions during actual circulation. Methods Based on the one-step method of the Huang model, the growth process of foodborne Escherichia coli (E. coli) in braised chicken legs was studied. Kinetic parameters for E. coli growth and survival were determined through multiple sets of isothermal experiments, ultimately yielding a second-order model describing the relationship between instantaneous colony count, temperature, time and initial colony count. The model was validated using simulation experiments. Results A significance analysis of differences was conducted between the measured growth colony counts of E. coli strains cultured under fluctuating temperatures and the predicted colony counts obtained by the model. The test showed that P=0.926>0.05, indicated that there was no significant difference between the predicted values and the measured values. Conclusion The second-order model constructed in this study can effectively simulate E. coli growth under fluctuating temperatures and is sufficiently reliable. The model, integrated with the R programming language, allows for rapid prediction of E. coli growth under fluctuating temperature conditions, providing a rapid and effective tool for risk assessment of braised meat products in actual circulation.

Objective To study the decontamination effects of different photosensitizers combined with blue light irradiation on Porphyra yezoensis. Methods This study first compared the bactericidal effects of 4 kinds of photosensitizers (curcumin, vitamin K3, riboflavin, and sodium copper chlorophyllin) and 3 kinds of wavelengths (405, 420 and 460 nm) on Escherichia coli and Staphylococcus aureus. Two kinds of blue light wavelengths (405 nm and 420 nm) and photosensitizers (curcumin and riboflavin) were then applied to fresh Pyropia yezoensi before drying. The influences of curcumin concentration, irradiation time, and distance were examined. The changes in hygienic indicator bacteria, color difference (ΔE), and nutritional content were measured before and after treatment and drying. Results The decontamination effect on fresh Pyropia yezoensi were consistent with those in the pure bacterial system. Blue light combined with photosensitizers exhibited stronger sterilization efficiency. The optimal treatment was 420 nm blue light combined with 100 μmol/L curcumin (5 cm distance, 150 min). The total viable count and coliforms in untreated fresh Pyropia yezoensi were 5.69 log CFU/g and 4.34 log CFU/g, respectively, which increased to 6.63 log CFU/g and 4.15 log CFU/g after primary drying. Total viable count and coliforms respectively decreased by 1.88 log CFU/g and 1.46 log CFU/g after treatment, and decreased by 1.94 log CFU/g and 1.35 log CFU/g after drying. ΔE of dried Pyropia yezoensi after treatment ranged between 0.5 and 1.5, indicating a slight but noticeable change, while no significant differences (P>0.05) were observed in nutritional components such as vitamin C and vitamin E. Conclusion After treatment with 420 nm blue light and 100 μmol/L curcumin, the total viable count of dried Pyropia yezoensi was reduced to 4.56-4.82 log CFU/g. Apart from slight color difference due to staining, there was no significant change in nutritional components. This study provides technical support for developing a safe, efficient and environmentally friendly preservation and processing method for Pyropia yezoensi.

Objective To develop a method for the simultaneous determination of 18 kinds of polychlorinated biphenyls (PCBs) in pork by isotope dilution-gas chromatography-high resolution magnetic mass spectrometry. Methods The optimal conditions of the accelerated solvent extractor and fully automated clean-up apparatus were determined by optimizing the extraction rate of the target substances using an accelerated solvent extractor and a fully automated clean-up instrument combined with isotope dilution method coupled with gas chromatography-high resolution magnetic mass spectrometry. A 4-factor, 3-level orthogonal test was designed using the extraction temperature, static extraction time and the number of cycles as the main factors to investigate the effect of the accelerated solvent extractor on the extraction rate of the fat content of the samples. The effects of the accelerated solvent extractor on the extraction rate of fat content of the samples were investigated. Results The linear relationships of the indicator PCBs (PCB28, PCBB52, PCB101, PCB118, PCB138, PCB153, PCB180) was good in the range of 0.5 to 200.0 pg/µL, and the linear range of the DL-PCBs (PCB77, PCB81, PCB105, PCB114, PCB123, PCB126, PCB156, PCB157, PCB167, PCB169, PCB189) had a good linear relationship in the range of 0.10 to 40.0 pg/µL, the correlation coefficients were all above 0.999. The limits of detection were in the range of 0.001-0.004 pg/g, and the limits of quantitation were in the range of 0.004-0.012 pg/g; the accuracy and precision of the fishmeal matrix standard reference material were tested by this study, and the PCBs levels were within the range with the relative standard deviations of 1.0%-7.5%. For the determination of actual samples of pork, and the contamination levels of PCBs in 18 kinds of were 1978.9-2530.8 pg/g fat. Conclusion This study is efficient, accurate, sensitive and suitable for the determination of 18 kinds of PCBs in pork.

Objective To develop a rapid and visual method for detecting Shigella by combining loop-mediated isothermal amplification (LAMP) with clustered regularly interspaced short palindromic repeats and associated protein 12b (CRISPR/Cas12b). Methods Based on the conserved invasion plasmid antigen H gene ipaH7 sequence of Shigella, LAMP primers were designed and screened to establish a LAMP method for detection of Shigella. The candidate sgRNAs were designed based on the target DNA sequence of LAMP amplified fragment, and then the sgRNA, which could specifically recognize and stimulate Cas12b cleavage, was screened. Finally, a rapid detection method for detecting Shigella was developed by combining LAMP with CRISPR/Cas12b, and the specificity and sensitivity were evaluated. Results A set of LAMP primers and sgRNA targeting Shigella ipaH7 were screened, and a LAMP CRISPR/Cas12b detection method was established. The detection could be completed within 1 hour with the lowest limit of detection of 1.1×10¹ CFU/mL for pure culture and 1.1×10¹ CFU/g for spiked pork samples, and no cross reactivity with other pathogens. Conclusion This study successfully establishes a rapid, sensitive and visual detection method for Shigella, which can achieve accurate detecting Shigella in food samples.

Objective To increase the production of exopolysaccharides (EPS) from lactobacillus by optimizing fermentation conditions and evaluate the antioxidant activity of the extracted EPS. Methods P1-10 was isolated as a high yield EPS producing lactobacillus from kefir grains and identified by 16S rDNA sequencing. Meanwhile, the effects of carbon source composition and content in the medium and fermentation time on the EPS yield of P1-10 were investigated and compared. Additionally, scanning electron microscopy and in vitro antioxidant study was studied from the obtained EPS as well. Results Among the 12 kinds of isolated strains from kefir grains, P1-10 formed gram-positive colonies under microscopic examination after Gram staining, could coagulate milk, and had a string length greater than 15 mm. It was identified as Pediococcus acidilactici strain (MH143596.1 Pediocuccus acidilactici strain D15) by 16S rDNA sequencing and the maximum content of EPS was 6.52 mg/mL. In addition, the optimal conditions for P1-10 were obtained under the condition of MRS (DeMan-Rogosa-Sharpe medium) medium with the carbon source replaced by 40 g/L sucrose and fermenting at 35 ℃, pH 6.0 for 60 hours, while the highest yield of EPS was 29.09 mg/mL. Furthermore, the surface of EPS under the scanning electron microscopy was relatively rough, with a sense of layering and different sizes voids. Moreover, the elimination rates of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) free radicals in the 1.0 mg/mL vitamin C (vitamin C, VC), EPS and fermentation supernatant were 86.21%, 95.03%; 81.32%, 93.91% and 58.54%, 65.73%, respectively. Conclusion P1-10 can effectively increase the extraction efficiency of EPS compared to the normal culture with the optimizing of the culture conditions. As for the in vitro antioxidant experiments, EPS is indicated a strong ability to scavenge free radicals and antioxidant capacity due to the highly DPPH and ABTS radical scavenging rates. This study may provide a theoretical basis for the screening, extraction and functional activity research of EPS from lactic acid bacteria.

Objective To study the effects of in vitro simulated digestion on the content of total polyphenols and antioxidant activity of Canarium album and its products. Methods The study investigated the changes in total polyphenol content and scavenging capacities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) cation (ABTS⁺) free radical, hydroxyl free radical and superoxide anion free radical during in vitro simulated gastrointestinal digestion using 5 samples: Canarium album polyphenol extract, fresh Canarium album, sweet Canarium album, salt-preserved Canarium album, and licorice-flavored Canarium album. Results The polyphenol content of the 5 samples in both the gastric and intestinal digestion stages was lower than that in the undigested samples. During the gastric digestion stage, the scavenging capacities of the 5 samples for ABTS⁺ free radicals and DPPH free radicals were significantly stronger than those of the undigested samples. In the intestinal digestion stage, the free radical scavenging capacities of most samples decreased. The hydroxyl radical scavenging capacities of Canarium album extract and fresh Canarium album were weaker than those of the other samples, but their scavenging capacities in the intestinal stage were stronger than those in the gastric stage. Significant differences were observed in the superoxide anion radical scavenging capacities among the 5 samples: The superoxide anion radical scavenging capacity of Canarium album polyphenol extract increased initially and then decreased over time during gastrointestinal digestion; the scavenging capacity of fresh Canarium album during gastrointestinal digestion was stronger than that of the undigested counterpart; due to the presence of processed ingredients, the scavenging capacities of sweet Canarium album, salte-preserved Canarium album and licorice-flavored Canarium album showed no obvious correlation with their polyphenol content. Conclusion Compared with the undigested samples, different Canarium album samples still exhibit good antioxidant activity after digestion. This study provides a reference for the further research and application of Canarium album polyphenols, and offers a theoretical basis for the development, deep processing and utilization of Canarium album and its products.

Objective To analyze the molecular epidemiological characteristics, virulence gene profiles, and distribution of antibiotic resistance genes of Vibrio parahaemolyticus (VP) isolated from foodborne diseases patients in Dalian City, Liaoning Province. Methods A total of 63 VP clinical isolates were collected from Dalian City in 2023. The whole genome sequencing, multilocus sequence typing, virulence genes and drug resistance genes were analyzed, and the clinical epidemiological data were combined for comprehensive analysis. Results July-September was the main epidemic period of VP. The results of sequence type (ST) showed that ST3 was the main epidemic group. The 63 strains carried both tlh and vcrD, and the carrying rate of tdh and vcrD2 virulence genes was 95.24%. All strains carried blaCARB-47, CARB-20, tet (35), tet (34) and CRP resistance genes, and one ST3 strain also carried aminoglycosides, sulfonamides and other resistance genes. There was a certain correlation between virulence gene carrying type and ST type, but there was no obvious clustering feature in the distribution of drug resistance genes. All isolates from patients with systemic symptoms carried tdh and vcrD2. Conclusion ST3 is the main epidemic group of VP in Dalian, Liaoning Province, which is widely distributed and has a high proportion of virulence genes. Speical attention should be paid to the risk of drug resistance transmission of ST3. This study provides a molecular epidemiological basis for the prevention and control of VP.

The contamination problem of Bacillus cereus seriously affects the food safety of China, the development of prevention and control technology against Bacillus cereus is urgent. Lactic acid bacteria, as a safe and efficient biological control method, have a good prospect in controlling Bacillus cereus precisely. Previous studies have found that Lactiplantibacillus, Lactobacillus and Lacticaseibacillus are the main genus of antagonistic bacteria. The antibacterial components against Bacillus cereus are mainly bacteriocins, organic acids and extracellular polysaccharides. The antagonistic mechanism mainly included destroying the integrity of cell membrane, inhibiting spore germination, biofilm formation and toxin expression, but the mechanism of internal gene expression regulation is still lack of in-depth exploration. This paper reviewed the progress in controlling of Bacillus cereus by lactic acid bacteria, summarized the lactic acid bacteria species, antibacterial compounds and their antagonistic mechanisms against Bacillus cereus, as well as the applications in food, also prospected the investigation of new types of microbial antibacterial components, the mechanism of action and the future applications, to provide new insights for the development of green prevention and control technologies of foodborne pathogens.