查看更多>>摘要：An advanced molecularly imprinted electrochemical sensor (MIECS) based on two-dimensional materials MXene was developed for determination of triclosan (TCS) in food samples for the first time. Two-dimensional titanium carbide (Ti3C2Tx) were introduced to improve electrochemical response of the MIECS. K+ ions were spontaneously inserted into Ti3C2Tx nanosheets to form K+-Ti3C2Tx by soaking in alkali solution, thus improving the sensitivity of the sensor. Molecularly imprinted polymers (MIP) were prepared by electropolymerization of para aminobenzoic acid (p-ABA), which can specifically recognize TCS. Under optimal conditions, the linear relationship between the current intensity and TCS concentration was obtained from 10 nmol L-1 to 50 mu mol L-1 with a low detection limit of 1.18 nmol L-1. The proposed MIECS showed good repeatability for detecting TCS at a concentration of 500 nmol L-1 solution by preparing five parallel modified electrodes, with a relative standard deviation (RSD) of 3.42%. At the spiked concentration levels of 0.05, 0.1, 0.5 mg L-1/mg kg-1, the recoveries range of TCS in peach juice, onions and fish samples were 86.38%-95.52%. The proposed MIECS combining the advantages of Ti3C2Tx and MIP exhibited good sensitivity and selectivity, providing strategy of utilizing MXenes in the construction of electrochemical sensing platform and holding great promise in the field of food safety.
查看更多>>摘要：Sorghum bran is a rich source of phenolic compounds with potent antioxidant and antimicrobial properties. This study investigated the effect of brown and black sorghum bran incorporation on the physicochemical and microbiological properties of beef sausages during cold storage at 4 degrees C. Results showed that the incorporation of sorghum bran in sausages, unexpectedly, promoted sausage discolouration, oxidation and pH fluctuation. The addition of sorghum bran in sausages significantly increased the texture values, including hardness, cohesiveness, resilience, gumminess and chewiness. In sorghum-added sausages, the total plate count, yeast & moulds count, and total Coliforms were inhibited only for the first 5-10 days, followed by a rapid increase, whilst the pathogenic Escherichia coli and Listeria spp. were inhibited throughout storage. Brown and black sorghum bran treatments had similar effects on sausages, and the effects were dependent on the amount of bran added. Although this study did not confirm the antioxidant effect of sorghum bran in meat application, it did demonstrate that sorghum bran has some antimicrobial activity, both of which require further evidence for verification.
查看更多>>摘要：Foodborne pathogens cause many food safety problems and Staphylococcus aureus (S. aureus) is one of them that seriously threaten human health through the ages. The conventional methods for S. aureus detection basically include culture-based methods and polymerase chain reaction, which are somewhat time-consuming and laborious, and require infrastructure and professional operations. In this article, a portable and visible detection platform for S. aureus was established based on CRISPR/Cas12a, which integrated with nucleic acid isothermal amplification, CRISPR/Cas12a detection, and lateral flow strips for final signal readout. The nuc gene specific in S. aureus and conservative 16S rDNA fragment in Staphylococcus genus were selected as the detection targets. The CRISPR detection platform achieved the sensitivity of 1 x 100 CFU/reaction of S. aureus in pure culturing samples and performed well in the specificity assay, while the sensitivity of 2 x 101 CFU/mL of S. aureus was obtained in artificially contaminated food samples. Consequently, this platform combined ultra-sensitivity, specificity, accuracy, portability, user-friendliness, and time-saving, which fulfills the actual requirements in the point-of-care testing of S. aureus and was also promising for further applications in the detection of other foodborne pathogens.
查看更多>>摘要：This study involved the fabrication of colorimetric sensor array system for rapid discrimination of adulterants in premium grade basmati rice. Purposely, low-grade white rice was used to adulterate the pure basmati rice at 5%, 10%, 15%, 25%, 50%, and 75% weight ratios. Sensor array system was used to capture the odors of prepared samples, resulting in color difference map based on chemical environment. The principal component analysis (PCA), hierarchical cluster analysis (HCA), and k-nearest neighbors (kNN) algorithm were subsequently used to identify the similarity between authentic and adulterated samples. A decent discrimination between authentic and adulterated rice samples was observed in the scatter plot of PCA and HCA dendrogram. The multilayered kNN models were able to effectively discriminate the prepared rice samples. The study concludes that fabricated sensor array system may be used as an effective tool for rapid discrimination of authentic and adulterated samples.
查看更多>>摘要：Escherichia coli O157 continues to be the most prevalent serotype among the Shiga toxin-producing E. coli infection cases confirmed in Europe. The reference methodology to detect this pathogen is lengthy and time consuming, thus we sought to develop a novel method that has low instrumentation requirement, and allowed naked-eye detection. Isothermal amplification of bacterial DNA was performed by Recombinase Polymerase Amplification, and the addition of SYBR Green I (RPA-SG), which allowed the visualization of results with nakedeye under a UV lamp. The results obtained in spiked ground meat samples by RPA-SG compared favorably to qPCR (relative sensitivity, specificity and accuracy higher than 90%, and Cohen's k of 0.81), with a limit of detection of 19 cfu/25 g. The novel methodology outperformed a culture-based approach, where none of the typical colonies were confirmed as O157 due to high concentration of interfering microorganisms. These results were obtained in one working day (same-day detection), having an average time to completion of about 5 h, including enrichment, DNA extraction, amplification and detection.
查看更多>>摘要：Ochratoxin A (OTA) is a common food contaminant that seriously threatens the safety and health of consumers. Here, an indirect competitive biotin-streptavidin-amplified enzyme-linked immunosorbent assay (icBA-ELISA) was developed for the sensitive detection of OTA by employing Fc-specific multi-biotinylated antibodies. An Fcbinding protein (Z-domain) carrying a photo-cross-linker (p-benzoylphenylalanine, Bpa) fused with tandem AviTag repeats, viz. Z(Bpa)-(AviTag)(n), was first constructed using the aminoacyl-tRNA synthetase/suppressor tRNA technique. Biotin molecules were covalently conjugated to antibodies mediated by the photoreactive biotinylated Z(Bpa)-(AviTag)(n), resulting in the Fc-specific multi-biotinylated antibodies (IgG-*Z-B-n conjugates) that were used to establish icBA-ELISA. Among the IgG-*Z-B-n-based icBA-ELISA, the IgG-*Z-B-5 conjugates exhibited a half maximal inhibitory concentration of 0.0519 ng mL(-1) and a limit of detection of 0.00944 ng mL(-1) for OTA. The sensitivity was improved 4.8 and 4.7 times compared with that of the chemical-coupled IgG-biotin conjugates. Thus, the proposed icBA-ELISA for the sensitive detection of OTA has remarkable potential applications for the detection of various toxins in food.
查看更多>>摘要：This study aimed to understand the effects of high-pressure processing (HPP) on the physicochemical quality, protein degradation and endogenous enzyme activities of shrimp (Penaeus monodon) stored in ice for 28-day storage. Headed shrimps were vacuum-packed and subjected to HPP (100, 300, and 500 MPa at 15 +/- 1 degrees C for 5 min). Results showed that HPP delayed microbial growth and reduced TVB-N values of shrimps as pressure increased. HPP did not completely inhibit pmteases activity, and excessive pressure promoted myofibrillar proteins denatured, which were unstable during chilled storage. Water-holding capacity and protein solubility were diminished with HPP. However, the mechanical properties were stable in 500 MPa-treated samples during chilled storage prevented by changes in the water phase state and distribution.
查看更多>>摘要：This study investigated the effect of superheated steam treatment (SST) and extrusion treatment (ET) on the changes of lipids in black soybean noodles (BSN) during storage. Degradation of lipids and formation of volatile compounds were closely related to the endogenous lipid-degrading enzyme activity. Both SST and ET could effectively inactivate lipase, lipoxygenase and peroxidase activity in black soybeans, and thus in the BSN. The content of polyunsaturated fatty acids decreased by 43.6% in non-heat-treated BSN during 7-week storage, whereas the reduction was only 23.0% and 20.7% in SST-190 degrees C and ET-130 degrees C groups, respectively. The degradation of tocopherols and tocotrienols, and formation of volatile compounds in the BSN was greatly inhibited during storage by the two heat processes, and ET seems to be more effective. In conclusion, both SST and ET were able to increase the lipid stability of BSN by inhibit the activity of lipid-degrading enzymes. This study could also provide more knowledge that assists to develop high quality of black soybean food products.
查看更多>>摘要：The purpose of this study was to investigate the changes in the main phenolic compounds and in vitro antioxidant activity of functional flavored yogurt supplemented with mulberry pomace (MP) during cold storage. Three anthocyanins (cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside and pelargonidin-3-O-glucoside) and six nonanthocyanin monomeric phenolics (resveratrol, catechol, catechin, rutin, quercitrin and quercetin) were identified in the MP. The MP powder addition significantly and dose-dependently increased the contents of total phenol (TPC), total anthocyanin (TAC) and individual phenolics and DPPH and ABTS free radical scavenging activity of the products. During the cold storage, TPC, TAC and contents of individual phenolics and antioxidant activity of MP-fortified yogurts gradually and significantly increased. Antioxidant activity of MP-fortified yogurts is highly related to TPC/TAC. MP-fortified yogurts exhibited the highest antioxidant activity on the 21st day of storage. The results showed that MP can be used as a natural antioxidant, providing a promising natural ingredient for the production of functional dairy products with improved nutritional value and biological activity.
查看更多>>摘要：The presence of deoxynivalenol (DON) has been repeatedly detected in cereal-based products collected from Spanish markets over the last years. Hence, the aim of this study was to conduct a systematic review and meta analysis of the concentration and prevalence of DON in cereals and cereal-based products from Spanish markets intended for human consumption, in order to integrate the available data. Then, an exposure assessment was performed based on national consumption data. Results revealed a strong impact of DON in breakfast cereals (pooled concentration = 105.34 ng/g; pooled prevalence = 58%) and bread and derived products (pooled concentration = 95.17 ng/g; pooled prevalence = 67%). Meta-regression showed a decrease in DON prevalence (p-value = 0.761) and concentration (p-value = 0.027) over the last 15 years. Exposure assessment outlined a high exposure to DON, especially in infants and children below 3 years old that showed a 175% and 119% of the tolerable daily intake (TDI). Bread and derived products were the main contributor to DON throughout age groups, with %TDI values ranging from 12% to 34%. Therefore, the here-presented results provide more evidence about the non-negligible impact of DON in Spain as result of cereal-based products consumption.
NSTL
Elsevier