查看更多>>摘要：Based on the verified application in China's National Foodborne Disease Outbreak Surveillance System, machine learning techniques have been indicated to have very positive effects. We summarize current positive attempts on improving case reporting, helping diagnosing and outbreak prediction. Based on the attempts, we propose a general framework to facilitate future improvements for a more intelligent foodborne disease surveillance system, which can greatly help human health.
查看更多>>摘要：Chicken breast, a food rich in protein, was deep-fried in soybean oil (SBO) at 140, 175 and 190 degrees C for 20 continuous batches, and the profiles of acid value (AV), peroxide value (PV), 2-tert-Butyl-1,4-dihydrobenzoquinone (TBHQ), and 2-tert-Butyl-1,4-benzoquinone (TBBQ) in SBO and fried chicken breast were determined. The results suggested that frying at 140 degrees C produced increased conversion of TBHQ to TBBQ and oxidation of the frying oil than at 175 degrees C, which was close to that found at 190 degrees C. The highest TBBQ peak concentration of 2.89 +/- 0.12 and 13.88 +/- 0.27 mg/kg for fried chicken breast and frying oil corresponded to the 7th and 6th frying batch at 140 degrees C, respectively. The experimental results on determination of the AV, PV, moisture and the content of oxygen in frying oil suggested that more moisture and oxygen were retained in oil when frying at 140 degrees C than that at 175 degrees C, which may explain the over-conversion of TBHQ to TBBQ when frying at low temperature. The results on aeration frying and water injection frying experiments indicated that moisture and oxygen had a great impact on the oxidation of TBHQ in frying oil.
查看更多>>摘要：The goal of this study was to elucidate the mechanism by which thymol caused membrane damages in Bacillus cereus cells and the feasibility of its application in the preservation of skim milk. The minimum inhibitory concentration (MIC) of thymol was determined using the broth microdilution method. The membrane potentials, intracellular adenosine triphosphate (ATP) concentrations, and pH gradients across the membrane were characterized using fluorescence spectroscopy. The degree of membrane damage and membrane structural integrity were observed under an electron microscope. The quantity of B. cereus in skim milk at different temperatures and concentrations of thymol was calculated using the plate counting method. As a result, the MIC of thymol against B. cereus BNCC 103930 was 0.625 mg/mL. Thymol significantly induced B. cereus cell dysfunction, membrane potential hyperpolarization, pH gradient dissipation, the blockade of ATP synthesis, and intracellular ATP depletion. Confocal laser scanning microscopy (CLSM) and field emission gun scanning electron microscope (FEGSEM) assays revealed pronounced membrane damages of B. cereus after thymol administration. Of note, low thymol concentrations, together with low-temperature storage, have the potential to control B. cereus in skim milk. These results indicated that thymol could be used as a food additive preventing B. cereus food poisoning.
查看更多>>摘要：Vanillin is the most characteristic compound in vanilla flavour. Since vanilla pods are very expensive, vanillin is mainly produced by synthetic and sometimes biosynthetic methods. Biosynthetic vanillin is called 'biovanillin' and can -by law-be labelled as 'natural'. The isotopic carbon ratio (expressed as 813C) is a widely established and valuable authentication parameter for vanillin. Furthermore, currently available data about 82H values indicate, that the isotopic hydrogen ratio can make a decisive contribution to the authentication of vanillin. One of the most recent developments is the bio-production of vanillin derived from glucose. However, very little is known about its isotopic composition. Here, we present the 813C and 82H values of glucose from corn and wheat and the vanillin that was derived from these. The isotopic composition of the glucose is clearly reflected in the resulting vanillin molecule. All 'glucose-vanillin' samples could be distinguished from vanillin originating from other sources when combining the 813C and 82H value.
查看更多>>摘要：Geotrichum citri-aurantii is the leading causes for sour rot diseases of postharvest citrus fruit, which results in a big loss of commercial value of citrus fruit. Cinnamic acid (CA) is widely used for the preservation of agricultural products due to its antiseptic and bactericidal effect. The effects of CA on the growth of G. citri-aurantii and its potential inhibitory mechanisms were investigated in this study. The results showed a complete inhibition in the growth of G. citri-aurantii caused by 400 mg L-1 CA in vitro, however, in vivo, the disease incidence in the citrus fruit decreased to 38.31% after the application of 4000 mg L-1. Scanning electron microscopy results showed that CA caused a shrinking and distortion of G. citri-aurantii hyphae, and transmission electron microscopy analysis revealed that the intracellular components were greatly leaked and degraded. When treated with 800 mg L-1 CA, 37.72% of G. citri-aurantii spores showed a destruction of plasma membrane integrity. The leakage of electrolyte and the intercellular constituents exosmosis results showed that CA led to a significant increase of the cell membrane permeability. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the protein test kit assay showed that the number of the protein bands reduced after 3 h of CA treatment compared with the control, suggesting that small-molecular and macromolecular substances had been leaked out of the cells. Soluble protein contents of the fungal cells treated with CA significantly dropped. All these results indicated that CA was effective in protecting citrus fruit from postharvest sour rot by damaging the cell membrane of G. citri-aurantii.
查看更多>>摘要：Food safety continues to be a challenge worldwide despite scientific advances, continuous improvement in food safety management systems and increasing academic debate on food safety. This paper aims to validate a new model of food safety cultural compliance to identify the challenges that organisations face in their pursuit of a positive food safety culture. A mixed-method approach was adopted via the quantitative analysis of a stage one 'Enlighten Questionnaire' involving 202 respondents using parametric statistics (ANOVA with appropriate PostHoc tests and t-tests). Hochberg's GT2 was used for the Post-Hoc tests due to different group sizes and appropriate non-parametric tests were also run to confirm these results. Qualitative analysis of stage two semistructured interviews totalling 40 participants and stage three focus groups each consisting of 3 groups of 9 employees equating to 27 participants was utilised. Thematic analysis was adopted to synthesise and cluster key themes. Our findings identify the misalignment of management and employees in the pursuit of establishing and embedding a positive food safety culture. Four key themes of the Enlighten Food Safety Culture Model (EFSCM) namely; Control, Co-operation, Communication and Competence were core cultural factors that could be used to realign management and employee behaviours to help stimulate a positive food safety culture.
查看更多>>摘要：The antimicrobial effects of low concentration electrolysed water (LcEW) on common foodborne pathogens have been well documented; however, the effects on six emerging Escherichia coli serotypes (the "big six") remained unknown. Using pea sprouts as the food matrix, this in vivo study examined the sanitising efficacy of a 10-min LcEW treatment against eight E. coli strains (non-pathogenic E. coli ATCC 25922, pathogenic E. coli O26:H11, O45:H2, O103:H11, O111, O121:H19, O145 and O157:H7). The metabolic responses of the strains were further analysed using nuclear magnetic resonance (NMR) spectroscopy. An overall negative correlation between the resistance to LcEW and the magnitude of metabolic variation was observed. The metabolic status and pathways of the most resistant O103:H11 and O45:H2 strains were the least affected. The O26:H11 and O145 strains which demonstrated the highest sensitivity to LcEW had an array of metabolites depleted and had multiple pathways involved in amino acid metabolism, energy metabolism as well as osmotic and oxidative protection perturbed. Distinctive metabolic responses were detected in ATCC 25922, suggesting that alternative stress defence mechanisms may be present in the non-pathogenic E. coli strain. Amongst the pathogenic strains, the most unique metabolic responses were illustrated by O121:H19. Overall, the study showed that the NMR-based metabolomics is promising in elucidating the metabolic changes of various E. coli strains in pea sprouts during an antimicrobial process. It also provides clue for controlling "big six" contamination in fresh produce.
Chavez, Ruben A.Cheng, XianbinHerrman, Tim J.Stasiewicz, Matthew J....
10页
查看更多>>摘要：Aflatoxin and fumonisin contamination distribution in corn is non-homogeneous. Therefore, bulk sample testing may not accurately represent the levels of contamination. Single kernel analysis could provide a solution to these problems and lead to remediation strategies such as sorting. Our study uses extensive single kernel aflatoxin (AF) and fumonisin (FM) measurements to (i) demonstrate skewness, calculate weighted sums of toxin contamination for a sample, and compare those values to bulk measurements, and (ii) improve single kernel classification algorithm performance. Corn kernels with natural contamination of aflatoxin and fumonisin (n = 864, from 9 bulk samples) were scanned individually twice for reflectance between the ultraviolet-visible-near infrared spectrum (304 nm-1086 nm), then ground and measured for aflatoxin and fumonisin using ELISA. Single kernel contamination distribution was non-homogeneous with 1.0% (n = 7) of kernels with >20 ppb aflatoxin (range 0 4.2 x 105 ppb), and 5.0% (n = 45) kernels with >2 ppm fumonisin (range 0 - 7.0 x 102 ppm). A single kernel weighted sum was calculated and compared to bulk measurements. Average difference in mycotoxin levels (AF = 0.0 log(ppb), FM = 0.0 log(ppm), weighted sum - measured bulk levels) calculated no systematic bias between the two methods, though with considerable range of -1.4 to 0.7 log(ppb) for AF and -0.6 to 0.8 log(ppm) for FM. Algorithms were trained on 70% of the kernels to classify aflatoxin (> 20ppb) and fumonisin (> 2ppm), while the remaining 30% of kernels were used for testing. For aflatoxin, the best performing algorithm was stochastic gradient boosting model with an accuracy of 0.83 (Sensitivity (Sn) = 0.75, Specificity (Sp) = 0.83), for both training and testing set. For fumonisin, the penalized discriminant analysis outperformed the rest of the algorithms, with a training accuracy of 0.89 (Sn = 0.87, Sp = 0.88), and testing accuracy of 0.86 (Sn = 0.78, Sp = 0.87). The present study improves the foundations for single kernel classification of aflatoxin and fumonisin in corn, and can be applied to high throughput screening. This study demonstrates the heterogeneous distribution of aflatoxin and fumonisin contamination at single kernel level, comparing bulk levels calculated from those data to traditional bulk tests, and utilizing a UV-Vis-NIR spectroscopy system to classify single corn kernels by aflatoxin and fumonisin level.
查看更多>>摘要：The present study is focused on the evaluation of the effect of grater type and fat content of the pulp on the spectral response obtained by near infrared hyperspectral imaging (NIR-HSI), when this technique is used to determine the rind percentage in Parmigiano Reggiano (P-R) cheese. To this aim, grated P-R cheese samples were prepared considering all the possible combinations between three levels of rind amount (8%, 18% and 28%), two levels of fat content of the pulp and two different grater types, and the corresponding hyperspectral images were acquired in the 900-1700 nm spectral range. In a first step, the average spectrum (AS) was calculated from each hyperspectral image, and the corresponding dataset was analysed by means of Analysis of Variance Simultaneous Component Analysis (ASCA) to assess the effect of the three considered factors and their two-way interactions on the spectral response. Then, the hyperspectral images were converted into Common Space Hyperspectrograms (CSH), which are signals obtained by merging in sequence the frequency distribution curves of quantities calculated from a Principal Component Analysis (PCA) model common to the whole hyperspectral image dataset. ASCA was also applied to the CSH dataset, in order to evaluate the effect of the considered factors on this kind of signals. Generally, all the three factors resulted to have a significant effect, but with a different extent according to the method used to analyse the hyperspectral images. Indeed, while fat content of the pulp and rind percentage showed a comparable effect on the spectral response of AS dataset, in the case of CSH signals rind percentage had a greater effect compared to the other main factors. However, CSH were also more sensitive to differences ascribable to the natural variability between diverse Parmigiano Reggiano cheese samples.
查看更多>>摘要：This study aimed to design a highly sensitive electrochemical aptasensor based on the dual-signal amplification strategy for detecting neomycin (NEO) in milk samples. The electronic signal of multi-walled carbon nanotubes (MWCNTs) was greatly improved due to the existence of ferrocene (Fc), which had good electron transfer ability. The silica hybridized mesoporous ferroferric oxide nanoparticles (Fe3O4@SiO2) were prepared by hydrothermal and chemical activation treatments, which had a large specific pore volume and a large specific surface area, they could fix more RNA aptamers (Apts) and promote the electron transfer of nanoparticle labels. A composite sandwich was formed between the two Apts (Aptl and Apt2) and the target. Also, Apt2 was modified by gold nanoparticles (AuNPs), enhancing the electrochemical signal. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to characterize the performance of the aptasensor in detail. Under optimized conditions, the response current differences of the electrochemical aptasensor exhibited a linear relationship toward the positive logarithm of NEO concentrations ranging from 5 x 10(-3) nM to 5 x 10(2) nM and a detection limit of 0.759 nM. The electrochemical aptasensor showed specificity and selectivity. In addition, the constructed aptasensor was successfully applied to the detection of NEO in milk. These results indicated that the aptasensor had potential applications in the actual monitoring of NEO.
NSTL
Elsevier