查看更多>>摘要：Some bacteria decarboxylate amino acids as a means of resisting acid stress. It is a mechanism commonly used by bacteria in fermented dairy products. The decarboxylation of histidine to histamine occurs frequently in some types of cheese, but high concentrations of histamine can be harmful to consumers. Not all amino acid decarboxylation products are, however, undesirable. GABA, the decarboxylation product of glutamate, has positive effects on human health. Although histamine and GABA accumulate in large quantities in many types of cheese, there is little information regarding their relationship, and that which is available is restricted to a few cheese varieties. The present work examines whether cheeses exist with high concentrations of GABA but safe concentrations of histamine. The GABA and histamine contents of 250 cheeses representing 143 European varieties were examined, and the technological, environmental and metabolic (TEM) traits governing their accumulation identified. Two TEM profiles were associated with high GABA contents and safe histamine concentrations. These findings could help the dairy industry select the best technological conditions for making GABA-rich, histamine safe cheeses.
Ben Hlima, HajerTavares, LolenyEnnouri, KarimBen Braiek, Olfa...
15页
查看更多>>摘要：During preparation, processing, and distribution, the spoilage of meat products has been causing a negative economic impact in the meat industries. In addition, lipid/protein oxidation and deterioration resulting from microorganisms' development are other concerns verified during the storage of meat and meat derivatives. In this sense, the meat industry has designed biopolymers-based materials containing biomolecules as active packaging to diminish losses and improve the shelf-life of these products. Here, we examined the loading of essential oils in the active films and coatings. Their impact on the chemico-physio-mechanico properties and antioxidant and antibacterial potential of the numerous biopolymer films for packaging meat and derived products are discussed. The potential use of essential oils incorporated into biopolymer network matrices of these films was also evaluated. This review also covers the biological effects of different types of edible films and the influence of these functional packaging on improving meat product quality. Interestingly, active films containing essential oil present a future approach and an environmentally friendly solution in the meat industry. In general, active food packaging revealed suitable technology to improve meat quality and reduce waste in the food industry.
查看更多>>摘要：Monascus spp. are filamentous fungi, which can produce Monascus azaphilone pigments, monaklin K and other beneficial secondary metabolites, and they can also produce a mycotoxin citrinin. In this study, the gene Mrrpd3, encoding Rpd3-like histone deacetylase was overexpressed to evaluate its regulation on the production of pigments and mycotoxin in Monascus ruber. RT-qPCR confirmed the expression of Mrrpd3 was increased in the Mrrpd3-overexpressing strain. UPLC detection showed Mrrpd3-overexpressing strain enhanced the citrinin content by 61.9%, 56.5% and 52.6% at the 3rd day, 9th day and 11th day, respectively. But overexpression of Mrrpd3 had no significant effect on pigments production. RT-qPCR results showed that overexpression of Mrrpd3 significantly increased the relative expression of citrinin biosynthetic pathway genes including pksCT, mrl1, mrl2, mrl4, mrl6 and mrl7. Western blot results suggested that overexpression of Mrrpd3 caused the decrease of acetylation modification of total protein and histone H3K27. Overall, these results indicate that Mrrpd3 plays an important role in regulating citrinin production of Monascus ruber. This study provides important insights into the mechanisms underlying the effects of the Mrrpd3 gene on the citrinin of Monascus ruber.
查看更多>>摘要：The simultaneous determination of aflatoxins (B-1, B-2, M-1 and M-2) in milk using a new sample pretreatment technique, the in-syringe dispersive micro-solid phase extraction (ISD mu SPE), coupled with high performance liquid chromatography with fluorescence detection is described. The separation of the aflatoxins were performed using C18 Hypersil gold (250 mm x 4.6 mm, 5 mu m) column at 40 degrees C under gradient elution for 35 min. The excitation and emission wavelengths of the fluorescence detector were at 360 nm and 440 nm, respectively. Online photo-chemical derivatization was used to enhance the detection of aflatoxin B-1. Several parameters such as type and amount of sorbent, vortex speed, vortex time and elution solvent were evaluated. Limits of detection (LOD) ranged from 0.003 to 0.005 ng mL(-1), limits of quantification (LOQ) ranged from 0.01 to 0.02 ng mL(-1), recoveries ranged from 73.0 to 109.6%, and relative standard deviations (RSDs) was less than 17.3%. The proposed method was succesfully applied to the analysis of aflatoxins in milk.
Park, Hee KyungWang, YirongFeng, HaoDong, Mengyi...
12页
查看更多>>摘要：Sprouts and microgreens present unique food safety risks. This study aimed to enhance microbial food safety of sprouts and microgreens via seed sanitation and antimicrobial spray. Radish, broccoli, and kale seeds inoculated with Escherichia coli O157:H7 were sanitized by a high acoustic power density (APD) ultrasound and mild heat (55 degrees C water) combined treatment for 5 min (US-5) or 10 min (US-10) that was compared with the FDArecommended 20 min, 20,000 mg/L chlorine treatment. E. coli O157:H7 populations of the seeds and sprouts/ microgreens were enumerated immediately after seed sanitation, on day-4 of germination, and after 4 more days in storage, or at the time of harvesting (day 7) for microgreens. Sanitated seeds were planted into germination mix and sprayed with water, 0.1% or 0.2% of calcium oxide (CaO) solution three times a day for 7 days. The US-5 treatment achieved a comparable E. coli O157:H7 reduction and sprout yield as the 20,000 mg/L chlorine treatment. The US-10 treatment exhibited a significantly higher E. coli O157: H7 reduction in all three seed types than the chlorine treatment but with a lower germination rate (p < 0.05). The 0.1% CaO spray effectively inhibited E. coli O157:H7 growth in kale microgreens while maintaining the yield and germination rate. For the same varieties of seeds regardless of treatment, microgreens harvested without roots showed much lower microbial loads (3.0-3.9 log CFU/g) than sprouts (6.0-7.0 log CFU/g) with roots. Overall, the US-5 treatment can be an adequate and environmentally friendly alternative to the traditional chlorine treatment. This study provided a practical solution to ensure microbial safety of the sprouts and presented evidence that microgreens are generally safer than sprouts.
查看更多>>摘要：Seafood is the product most susceptible to fraudulent activities. In particular, the cephalopod sector is affected mainly by the replacement of fresh by frozen-thawed product either immediately or after bleaching with hydrogen peroxide. Such activities undermine the consumers' confidence in the fish industry and in the effectiveness of the government's food control programme. Currently, the conventional analyses performed to check food authenticity are time-consuming and require skilled personnel, and thus are not applicable to on-site control. The aim of the present study was to develop classification models to discriminate cuttlefish (Sepia officinalis) according to physical status and hydrogen peroxide treatment among fresh, frozen-thawed and frozenthawed hydrogen peroxide-treated samples. A total of 669 cuttlefish spectra were collected, under real conditions, using a portable near-infrared spectrometer (902-1680 nm) operating in reflectance mode. Classification models were developed and then validated using a Support Vector Machine algorithm. Performance of the models was tested through external and hold-out validation according to their accuracy, sensitivity, specificity and Matthew correlation coefficient. The best performance was observed in discriminating between fresh and frozen-thawed product, in which were observed in hold-out validation 0.97 in accuracy and sensitivity, 0.96 in specificity, and 0.92 in Matthew correlation coefficient; whereas, an accuracy of 0.93, sensitivity of 0.89, specificity of 0.94 and Matthew correlation coefficient of 0.83 were found in external validation. However, sample classification according to bleaching treatment showed high performance when fresh samples were excluded. Such achievements confirm the applicability of near-infrared spectroscopy to the on-site inspection of cuttlefish and the control of the fraudulent activity of replacing fresh fish with product mislabelled as such.
查看更多>>摘要：Meat adulteration is a persistent problem in the food industry in many countries. This unfair practice can potentially not only affect the economy of a country but also the confidence and health of its citizens. Additionally, it can aggravate allergies or damage religious beliefs (e.g., Muslims). The aim of this study was to develop a simple and rapid technique for the on-site inspection of several targets using multiplex polymerase chain reaction (PCR) coupled with DNA strip for detecting contamination with products from five non-halal animals (monkeys, dogs, rats, pigs, and cats) in foods certified to be halal. Species-specific primers were retrieved from the mitochondrial genes of each non-halal animal and modified with a tag sequence and biotin. The selected primers showed high specificity for each non-halal animal. The PCR products obtained after amplification were detected using DNA strip. The limit of detection ranged from 0.01 ppm to 1 ppm (dogs, 1 ppm; cats, 0.1 ppm; pigs, 0.01 ppm; monkeys, 0.01 ppm; and rats, 0.01 ppm). Beef meatballs spiked with nonhalal meat in different ratios were prepared to validate the developed technique, which presented 100% accuracy in detection. In addition, the developed technique was applied to verify 115 samples of meat products commercially available in Thailand. Sixteen samples were contaminated with pig DNA, but contamination with the DNA of other non-halal animals was not found. Therefore, this technique has high potential for on-site monitoring of non-halal animal contaminants in halal products in Thailand.
查看更多>>摘要：Polydopamine/polystyrene fibers mat (PDA-PS FsM) was prepared as a novel solid phase extraction (SPE) adsorbent for the simultaneous extraction of multi-class veterinary drug residues in animal-original foods. On this basis, a screening method for the determination of 18 veterinary drug residues in 8 classes by UPLC-MS/MS was established. PDA-PS FsM was confirmed to have good adsorption-desorption performance. By comparing the matrix effect before and after SPE, it was proved that PDA-PS FsM had significant matrix removal ability. The whole sample preparation process was less than 5 min, only 20 mg PDA-PS FsM and 2.5 mL of organic solvent were needed. The limits of detection of the target analytes ranged from 0.1 to 3.2 mu g kg(-1), and the recoveries ranged from 92.59% to 102.86%, with the intra-day and inter-day relative standard deviations of 2.11%- 10.57%, revealing satisfactory accuracy and precision. Finally, the practicability of the method was evaluated.
Kim, Yong-KyoungBaek, InsuckLee, Kyung-MinQin, Jianwei...
9页
查看更多>>摘要：Aflatoxins, commonly found in corn and corn-derived products, can cause severe illness in animals and humans if consumed in significant amounts. Early detection is critical to preventing illness, but the most sensitive and effective of commonly used screening tools for aflatoxins are expensive and cumbersome methods based on chromatography or imunoassays that require technical expertise to perform. Multiple hyperspectral imaging techniques, including reflectance in the visible and near-infrared (VNIR) region and short-wave infrared (SWIR) region, fluorescence by 365 nm ultraviolet (UV) excitation, and Raman by 785 nm laser excitation, were used for detection of aflatoxin in ground maize. Four classification models based on linear discriminant analysis (LDA), linear support vector machines (LSVM), quadratic discriminant analysis (QDA), and quadratic support vector machines (QSVM) algorithms were developed for classification with each hyperspectral imaging mode. The multivariate classification models in combination with different preprocessing methods were applied for screening of maize samples naturally contaminated with aflatoxin. The classification accuracies for fluorescence with QSVM, VNIR with QSVM, SWIR with LSVM, and Raman with LSVM were 95.7%, 82.6%, 95.7%, and 87.0%, respectively, with no false-negative error at the cutoff of 10 mu g/kg. The SWIR and fluorescence models showed slightly higher performance accuracies, suggesting that they may be more effective and efficient analytical tools for aflatoxin analysis in maize compared to conventional wet-chemical methods. These methods show promise as inexpensive, and easy-to-use screening tools for food safety, to rapidly detect aflatoxins in maize or other food ingredients intended for animal or human consumption.
查看更多>>摘要：Analytical methods able to differentiate fresh from frozen/thawed fish products are needed for suppliers and official authorities to prevent food frauds. In this study we applied a metabolomics approach to identify markers of freezing/thawing in skinless European sea bass (Dicentrarchus labrax) fish fillets. To this end, one hundred and twenty fish samples (sixty fresh and sixty frozen/thawed) were analysed in positive and negative ion modes by liquid chromatography coupled to high resolution mass spectrometry (LCHRMS). A combination of a supervised classification method by partial least square-discriminant analysis (PLSDA), and Recursive Feature Elimination (RFE) allowed us to discover the most informative metabolites useful to codify fresh and defrosted European sea bass. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) metabolites were identified as the most relevant predictors. These were used to build a model capable of classifying European sea bass samples according to their fresh or frozen/thawed condition. The model showed accuracy, sensitivity and specificity of 100 %, when tested to an independent set of European sea bass undergoing the same experimental conditions. EPA and DHA were found to be altered even in a set of twenty fresh and frozen/thawed Atlantic salmon (Salmo salar), opening the way for the development of a targeted method aimed at providing robust species-independent tests to be applied in the seafood chain by producers and competent authorities.
NSTL
Elsevier