Cronobacter spp. is a group of foodborne opportunistic pathogens widely present in the natural environment, characterized by their ability to tolerate desiccation and high osmolarity, enabling them to survive for extended periods in dried milk powder. Infant formula products may become contaminated during production, transportation, storage, and even during the reconstitution process. Infection with Cronobacter spp. can lead to severe illnesses such as bacteremia, meningitis, necrotizing enterocolitis in infants, and may result in serious neurological sequelae or even death. Therefore, establishing efficient and accurate detection methods for Cronobacter spp. is crucial for preventing and controlling these diseases, and holds significant importance in ensuring the quality and safety of infant formula products. Currently, the main detection methods for Cronobacter spp. include traditional culture-based methods, molecular biology methods, and immunological methods, with numerous studies in recent years reporting various degrees of improvement and optimization based on these methods. This article systematically reviewed the principles, advantages, and disadvantages of the various detection methods currently available for Cronobacter spp., aiming to provide a reference for further research in this field and for the optimization and updating of national standards and industry standards.

Food origin traceability technology is an important technical means for the effective implementation of food origin traceability and the protection of regional brands and specialty products. China has established a number of food safety standard systems, including “geographical indications of Chinese agricultural products”. There is an increasing demand for food origin discrimination at home and abroad, and the characteristics of volatile organic compounds (VOCs) are closely related to food origin, which can be used to characterize the differences between different products of the same kind of food. Gas chromatography-ion mobility spectrometry (GC-IMS) technology is a new technology developed in recent years for the determination of VOCs, which has the advantages of good separation effect, fast detection speed and high sensitivity, and has the potential to become an effective technical means for origin tracing. This paper introduced the working principle and characteristics of GC-IMS technology, summarized the progress of the application of GC-IMS technology in the origin traceability of animal and plant-derived foods in recent years, and discussed the future development direction of GC-IMS technology, in order to provide technical reference for the continuous expansion of the application of GC-IMS technology in the origin traceability of food.

Objective To compare the differences in spectral characteristics and monocyte immune effects for bacterial endotoxin from different sources. Methods Ultraviolet absorption spectrum and three-dimensional fluorescence spectrum were used to identify excipients (polyethylene glycol 8000 and α-lactose) and biological impurities (protein and nucleic acid) in 5 kinds of control standard endotoxin. Biological contamination was further confirmed by the detection of Toll-like receptors (TLRs) in HL-60 cells. The monocyte activation test was used to compare the release of the inflammatory cytokines interleukin 6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) caused by 5 kinds of endotoxins on HL-60 cells. Results As for control standard endotoxin, absorption peaks related to excipients were observed in ultraviolet absorption spectrum, while fluorescence peaks related to excipients and proteins were shown in three-dimensional fluorescence spectrum. The expression levels of TLRs of HL-60 cells indicated that protein contamination was more significant than nucleic acid contamination. All endotoxins induced improvement in cellular IL-6 and IL-1β gene relative expression levels and their protein mass concentrations in HL-60 cells. However, the TNF-α gene relative expression levels and its protein concentrations were not elevated. Endotoxins from the same or different bacterial strains had significant differences in their ability to induce inflammation under the same endotoxin activities. Conclusion Excipients and protein contamination of endotoxins are identified by spectral detection, while proteins and nucleic acids in biological impurity are confirmed by the TLRs assay of HL-60 cells. Molecular structure of endotoxins, as well as protein contamination influence the ability of endotoxins to induce the release of the inflammatory cytokines.

Objective To study the suitability of different varieties of Dioscorea esculenta for vacuum frying. Methods Nineteen varieties of Dioscorea esculenta widely cultivated in China were taken as raw materials. Six quality indexes of fried Dioscorea esculenta chips, namely the yield rate, sensory score, breaking force, adhesiveness, color difference, oil content and flavor, were measured, and difference analysis was carried out. Correlation analysis, principal component analysis, stepwise regression analysis methods were applied to explore the model fitting degree and the significance of the regression model. K-means clustering analysis method was used to preliminarily divide the processing suitability of the 19 Dioscorea esculenta varieties. Results Differences were found in the shape, size and color of fried Dioscorea esculenta chips among the 19 Dioscorea esculenta varieties, and correlations existed among the indexes. Taking the yield rate of Dioscorea esculenta (X₁), color difference value L^* (X₂), sensory score (X₃), breaking force (X₄), adhesiveness (X₅) and oil content (X₆) as the initial independent variables, principal component analysis could be conducted and a quality evaluation model for fried Dioscorea esculenta chips was constructed, which was Y=1.02-3.37X₁-0.19X₂+0.16X₃+0.18X₄+3.01X₅+2.43X₆. Among the 19 varieties, Zhan Shu 12, Mian Zi 12, Bai Shu, Chuan Zi Shu No. 6 and 317 were suitable for making chips; Yu Shu 27, Xu Yu No. 31, Qian Zi Shu No. 1, Wan Shu No. 5, Xiang Shu 98, Yu Shu 17, Zi Yun Hong Shu, Yu Shu 198, Qian Shu No. 8, Shang Shu 19, Kao Shu, Yu Shu 9 and Long Shu 9 were basically suitable for making chips; while Tong Shu No. 2 was not suitable for making chips. Conclusion The research results can be referred to when the Dioscorea esculenta industry in China selects specific varieties for chip processing.

Objective To study the growth heterogeneity of different serotypes of Vibrio parahaemolyticus (VP) under different culture conditions, and to establish growth prediction models for epidemic strains (O3:K6, O10:K4). Methods Seventeen VP strains of different serotypes were selected as the research objects, and different culture conditions were set, including salinity (0.5%-10.0%), pH (3.0-11.0) and temperature (16-50 ℃). The modified Gompertz model was used to establish the primary growth model. The optimal growth range was determined by comparing the maximum OD value (Y_max), the Lag time (λ) and maximum specific growth rate (μ_max). The second-order response surface growth model was established by Design-Expert 13 software. Results There was growth heterogeneity among VP strains. The coefficient of variation for differences in growth parameters μ_max and Y_max between VP strains at salinity levels of 1.0%-3.0%, pH of 7.0-9.0, and temperatures of 20-40 ℃ was lower than that under other culture conditions. The growth ability of the epidemic strains (serotype O3:K6, O10:K4) was significantly greater than that of other serotypes when the salinity was 7.0%, the pH was 10.0, and the temperature was 16 ℃, with a statistically significant difference (P<0.05). The determination coefficients of the first-order growth models fitted under different salinity and temperature were greater than 0.98, and the correlation coefficients under different pH were greater than 0.9. The second-order response surface growth model was significant (P<0.05), and the determination coefficient was greater than 0.94. Conclusion There is growth heterogeneity among VP strains, but in certain extreme conditions, there are more obvious growth differences between different serotypes. The modified Gompertz model and the second-order response surface growth model can be used to analyze and predict the growth of VP under different experimental conditions, which can provide reliable and safe prediction for the growth trend of VP.

Objective To establish an automatic, fast and high-resolution detection method for 5 kinds of common pathogenic bacteria in aquatic products, and improve the efficiency and accuracy of detecting pathogenic microorganisms in aquatic products. Methods Genes of owpW, tlh, invA, femA, and prfA from Vibrio cholera, Vibrio parahaemolyticus, Salmonella, Staphylococcus aureus, and Listeria monocytogenes were amplified by multiple polymerase chain reaction (PCR). PCR products were used as templates for single nucleotide extention and molecular weight of the extended probes was detected on the mass spectrometer. The molecular weight of probes for genes owpW、tlh、invA、femA and prfA were 4848, 5435, 5890, 6560 and 7096 Da. The molecular weights of the extended probes were 5119 Da (plus A), 5697 Da (plus T), 6137 Da (plus C), 6822 Da (plus T) and 7383 Da (plus G), respectively. This finally determined system was verified by reproducibility test, specificity test, sensitivity test and detection test of artificially contaminated aquatic samples. Results Using a sample of mixed DNA from 5 kinds of different bacteria as a template for nucleic acid mass spectrometry detection, the corresponding 5 kinds of probes could be extended simultaneously with an extension efficiency greater than 80%. The above 5 kinds of bacteria would not be detected in samples using interfering bacteria as templates. The sensitivity for detecting Salmonella, Staphylococcus aureus, Listeria monocytogenes, Vibrio parahaemolyticus, and Vibrio cholerae could reach 150, 350, 160, 130, and 180 CFU/mL, respectively. Conclusion This method demonstrates good reproducibility, specificity, and sensitivity, and has a high degree of automation, which can meet the detection needs of the above 5 kinds of microorganisms in aquatic products simultaneously.

Aquatic products, as a significant source of high-quality animal protein, play a crucial role in the fishery economy of China. The aquatic product processing industry not only enhances the prosperity of this sector but also fosters the development of related industries, thereby serving as a vital link in the comprehensive advancement of fisheries. The standard system for aquatic product processing serves as the foundational institution for ensuring the high-quality development of China’s fishery industry. Enhancing the construction of the aquatic product processing system, refining the standard system, and fostering the healthy development of the aquatic product processing industry hold immense significance in safeguarding the quality and safety of aquatic products in China. This paper examined the current status of the standard system for aquatic product processing in China and proposes ideas, principles, and frameworks for its establishment. It was recommended that emphasis be placed on the coordinated development of an integrated industrial chain processing standard system while prioritizing quality evaluation methods for aquatic products. Furthermore, it was essential to expedite the formulation of standards encompassing general applicability, product quality grading and detection methodologies, processing quality control management and traceability protocols, storage and preservation practices, as well as cold chain logistics. These efforts aim to facilitate effective alignment between standards across both upstream and downstream segments of the industrial chain and provide standardized support for fostering sustainable growth within China’s aquatic product processing industry.