Identification and Safety Evaluation of Ochratoxin A Transformation Product in Rapeseed Oil Refining Process.

Ochratoxin A (OTA) is an important mycotoxin detected in edible oil, and it can be effectively removed by classical edible oil refining processes. However, the fate of OTA in the refining process has not been reported. In this study, we systematically tracked the OTA changes during the oil refining process by fortifying 100 µg/kg OTA in crude rapeseed oil. Results showed that about 10.57%, 88.85%, and 0.58% of OTA were removed during the degumming, deacidification, and decolorization processes. Among them, 16.25% OTA was transferred to the byproducts, including 9.85% in degumming wastewater, 5.68% in soap stock, 0.14% in deacidification wastewater, and 0.58% in the decolorizer; 83.75% OTA was found to transform into the lactone ring opened OTA (OP-OTA) during the deacidification stage, which is attributed to the hydrolysis of the lactone ring of OTA in the alkali refining. The OP-OTA was verified to distribute in the soap stock, and small amounts of OP-OTA could be transferred to deacidified wastewater when the OTA pollution level reached 500 µg/kg in crude rapeseed oil. The OP-OTA exhibited strong toxicity, especially nephrotoxicity, as reflected by the cell viability assay and in silico toxicity. Therefore, the safety of the soap stock processing products from OTA-contaminated rapeseed deserves attention.

Membrane-based lateral flow immunochromatographic strip with nanoparticles as reporters for detection: A review.

Membrane-based lateral flow immunochromatographic strip (LFICS) is widely used in various fields because of its simplicity, rapidity (detection within 10min), and low cost. However, early designs of membrane-based LFICS for preliminary screening only provide qualitative ("yes/no" signal) or semi-quantitative results without quantitative information. These designs often suffer from low-signal intensity and poor sensitivity and are only capable of single analyte detection, not simultaneous multiple detections. The performance of existing techniques used for detection using LFICS has been considerably improved by incorporating different kinds of nanoparticles (NPs) as reporters. NPs can serve as alternative labels and improve analytical sensitivity or limit of detection of LFICS because of their unique properties, such as optical absorption, fluorescence spectra, and magnetic properties. The controlled manipulation of NPs allows simultaneous or multiple detections by using membrane-based LFICS. In this review, we discuss how colored (e.g., colloidal gold, carbon, and colloidal selenium NPs), luminescent (e.g., quantum dots, up-converting phosphor NPs, and dye-doped NPs), and magnetic NPs are integrated into membrane-based LFICS for the detection of target analytes. Gold NPs are also featured because of their wide applications. Different types and unique properties of NPs are briefly explained. This review focuses on examples of NP-based LFICS to illustrate novel concepts in various devices with potential applications as screening tools. This review also highlights the superiority of NP-based approaches over existing conventional strategies for clinical analysis, food safety, and environmental monitoring. This paper is concluded by a short section on future research trends regarding NP-based LFICS.

Magnetic nano-beads based separation combined with propidium monoazide treatment and multiplex PCR assay for simultaneous detection of viable Salmonella Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes in food products.

We developed a rapid and reliable technique for simultaneous detection of Salmonella Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes that can be used in food products. Magnetic nano-beads (MNBs) based immunomagnetic separation (IMS) was used to separate the target bacterial cells while multiplex PCR (mPCR) was used to amplify the target genes. To detect only the viable bacteria, propidium monoazide (PMA) was applied to selectively suppress the DNA detection from dead cells. The results showed the detection limit of IMS-PMA-mPCR assay was about 10(2) CFU/ml (1.2 × 10(2) CFU/ml for S. Typhimurium, 4.0 × 10(2) CFU/ml for E. coli O157:H7 and 5.4 × 10(2) CFU/ml for L. monocytogenes) in pure culture and 10(3) CFU/g (5.1 × 10(3) CFU/g for S. Typhimurium, 7.5 × 10(3) CFU/g for E. coli O157:H7 and 8.4 × 10(3) CFU/g for L. monocytogenes) in spiking food products samples (lettuce, tomato and ground beef). This report has demonstrated for the first time, the effective use of rapid and reliable IMS combined with PMA treatment and mPCR assay for simultaneous detection of viable S. Typhimurium, E. coli O157:H7 and L. monocytogenes in spiked food samples. It is anticipated that the present approach will be applicable to simultaneous detection of the three target microorganisms for practical use.

Cloning and sequence analysis of the full-length cDNA of a novel yp05 gene associated with citrinin production in Monascus aurantiacus.

OBJECTIVE: To obtain the full-length cDNA of a novel gene (named yp05) associated with citrinin production-related genes in Monascus aurantiacus. METHODS: Total RNA was extracted from mycelium, 3' and 5' cDNA end of yp05 gene was amplified using smart trace cDNA amplification kit, and the full-length cDNA of a novel gene (named yp05) was obtained from the electronic assembly of 3'-RACE and 5'-RACE products. RESULTS: This yp05 gene was 787 bp including a 597 bp open reading frame (ORF) and encoded a deduced protein with 199 amino acid residues, and the amino acid sequence of this protein was found similar with the sequences of many fungal manganese-superoxide dismutases in the GenBank with the aid of BLASTp. The transcription of yp05 gene in Monascus strains was analyzed with the aid of Northern blotting. The transcription of yp05 gene was only detected in Monascus strains, provided that citrinin was produced. CONCLUSION: The transcription of yp05 gene belongs to differential expression genes of citrinin yielded from Monascus and has no correlation with the biosynthesis pathway of red pigments.

Synergistic antidigestion effect of Lactobacillus rhamnosus and bovine colostrums in simulated gastrointestinal tract (in vitro).

Probiotics and bovine colostrums had been proven to be beneficial for human health. Lactobacillus rhamnosus ZDY114 and anti-Helicobacter pylori bovine colostrums were used for the preparation of microecological additives, and their synergistic antidigestion effect in the simulated gastrointestinal tract (in vitro) was investigated. Either L. rhamnosus or purified IgG from immune colostrums was very sensitive in simulated gastric environment and slightly sensitive in simulated intestinal tract. No viable counts were recovered from the solution of dissolved freeze-dried powder (7.14 log(10) CFU/ml) of L. rhamnosus when digested at pH 3.0 with pepsin for 30 min. Activity of purified IgGs from immune colostrums could not be detected when digested at pH 3.0 with pepsin for 30 min; 29% titer could be detected when digested at pH 8.0 with trypsin for 5 h. The IgGs in nonpurified immune colostrums presented stronger resistance against gastrointestinal digestion than purified IgGs. Moreover, the combination of L. rhamnosus ZDY114 and immune colostrums strengthened their antidigestion ability. Even under pH 3.0, 4.0 with pepsin, the titer of anti-HP IgG maintained above 123 and 83.3%, respectively. Similarly, that titer was above 93.3% when digested at pH 8.0 with trypsin for 4.5 h. In conclusion, L. rhamnosus and anti-Helicobacter pylori bovine colostrums had synergistic antidigestion effect in simulated gastrointestinal tract (in vitro).

Synergistic effects of Lactobacillus rhamnosus ZDY114 and bovine colostrums on the immunological function of mouse in vivo and in vitro.

The synergistic effects of Lactobacillus rhamnosus and bovine colostrums on the immunity of mice in vivo and in vitro were investigated. Eight- to ten-week-old mice were used for two series experiments; one part of mice were immunocompromised by intraperitoneal injections of cyclophosphamide. In series I, immunocompromised mice were continuously fed with diet A (L. rhamnosus ZDY114 5 x 10(7) CFU/kg), B (bovine colostrums 0.5 g/kg), C (combination of diet A and B), and D (sterile saline) for 4 weeks and killed. Thereof, phagocytosis ratio and index of macrophage to chicken red blood cells in abdominal cavity and lymphocyte transformation rate were determined. In series II, both normal and immunocompromised mice were used to investigate the in vitro stimulation of lymphocyte proliferation by substances from the overnight culture of L. rhamnosus ZDY114 by the MTT colorimetric method. Compared with diet D, in the diet A, B, and C groups, the phagocytosis ratio of macrophages increased by 1.63, 1.54, and 2.3-fold, respectively, and the lymphocyte transformation ratio by 1.78, 2.08, and 2.35-fold, respectively. In vitro test with MTT showed that 3, 10, 50 kD substances from the overnight culture of L. rhamnosus ZDY114 significantly increased the growth of lymphocyte by 1.63, 1.53, and 1.34-fold, respectively. In conclusion, L. rhamnosus and bovine colostrums can enhance the functions of immune system supported by lymphocytes and peritoneal macrophages either in vivo or in vitro.