Oxidative stress and viral Infections: rationale, experiences, and perspectives on N-acetylcysteine

This article explores current evidence on the role of oxidative stress in viral infections, and on the use of antioxidant drugs as adjunctive treatment. MEDLINE/PubMed was searched for appropriate keywords, and preclinical and clinical studies with reviews were retrieved and examined by authors. Old and current evidence shows that GSH content reduction is the main mechanism of redox imbalance in viral-infected cells. Clinical studies found that GSH levels are depleted in patients with viral infections such as HIV and SARS-CoV. Viral infections activate inflammation through different pathways, and several of these mechanisms are related to oxidative stress. NAC is a precursor of GSH, and many of its intracellular effects are mediated by GSH replenishment, but it also activates some anti-inflammatory mechanisms. NAC has an excellent safety profile and better oral and topical bioavailability than GSH. These characteristics make NAC a suitable option as a repurposed drug. Adjunctive antioxidant treatment may improve the outcomes of antiviral therapies. Current evidence supports the rationale for this practice and some clinical experience showed encouraging results.

144 Probable Delirium is A Presenting Symptom of COVID-19 in Frail, Older Adults: A Study of Hospitalised and Community-Based Cohorts

Introduction

COVID-19 exhibits a more severe disease course in older adults with frailty. Awareness of atypical presentations is critical to facilitate early disease identification. This study aimed to assess how frailty affects presenting symptoms of COVID-19 in older adults.

Methods

Observational study of two distinct cohorts: (i) Hospitalised patients aged 65 and over; unscheduled admission to a large London teaching hospital between March 1st, 2020-May 5th, 2020; COVID-19 confirmed by RT-PCR of nasopharyngeal swab (n = 322); (ii) Community-based adults aged 65 and over enrolled in the COVID Symptom Study mobile application between March 24th (application launch)-May 8th, 2020; self-report or report-by-proxy data; reported test-positive for COVID-19 (n = 535). Multivariable logistic regression analysis performed on age-matched samples of both cohorts to determine associations between frailty and symptoms of COVID-19 including delirium, fever and cough.

Results

Hospital cohort: there was a significantly higher prevalence of delirium amongst the frail sample, with no difference in fever or cough. Of those presenting with delirium, 10/53 (18.9%) presented with delirium as the only documented symptom. Community-based cohort: there was a significantly higher prevalence of probable delirium in the frail sample, and also of fatigue and shortness of breath. Of those reporting probable delirium, 28/84 (33%) did not report fever or cough.

Conclusions

This study demonstrates a higher prevalence of delirium as a presenting symptom of COVID-19 infection in older adults with frailty compared to their age-matched non-frail counterparts. Clinicians should suspect COVID-19 in frail older adults presenting with delirium. Early detection facilitates infection control measures to mitigate against catastrophic spread and preventable hospitalisations and deaths amongst this population. Our findings emphasise the need for systematic frailty assessment for all acutely ill older patients in both hospital and community settings, as well as systematic evaluation of any change in mental status.

Diagnostic value of cutaneous manifestation of SARS-CoV-2 infection

Background

One of the challenging aspects of SARS‐CoV‐2 infection is its diverse multisystemic disease presentation.

Objectives

To evaluate the diagnostic value of cutaneous manifestations of SARS‐CoV‐2 infection and investigate their duration and timing in relation to other COVID‐19 symptoms.

Methods

We used data from 336 847 UK users of the COVID Symptom Study app to assess the diagnostic value of body rash or an acral rash in SARS‐CoV‐2 infection, and data from an independent online survey of 11 544 respondents to investigate skin‐specific symptoms and collect their photographs.

Results

Using data from the app, we show significant association between skin rashes and a positive swab test result (odds ratio 1·67, 95% confidence interval 1·42–1·97). Strikingly, among the respondents of the independent online survey, we found that 17% of SARS‐CoV‐2‐positive cases reported skin rashes as the first presentation, and 21% as the only clinical sign of COVID‐19. Together with the British Association of Dermatologists, we have compiled a catalogue of images of the most common skin manifestations of COVID‐19 from 400 individuals (https://covidskinsigns.com), which we have made publicly available to assist clinicians in recognition of this early clinical feature of COVID‐19.

Conclusions

Skin rashes cluster with other COVID‐19 symptoms, are predictive of a positive swab test, and occur in a significant number of cases, either alone or before other classical symptoms. Recognizing rashes is important in identifying new and earlier cases of COVID‐19.

What is already known about this topic?

Several studies conducted in hospital settings reported that patients with COVID‐19 presented with unusual skin rashes, including urticarial rashes, vesicular lesions and, less frequently, chilblains in fingers or toes.

What does this study add?

We confirmed, in a community‐based setting that also includes milder forms of the disease, that the presence of a skin rash is predictive of SARS‐CoV‐2 infection.

We provide a website with photos of skin manifestations to help healthcare professionals in diagnosing COVID‐19.

Skin rashes should be taken into account to provide a quick COVID‐19 diagnosis to curb the spread of the disease.

Linked Comment: Naldi. Br J Dermatol 2021; 184:793–794.

Survey of Fumonisin Production by Fusarium Isolated from Cereals in Europe

Strains of Fusarium isolated from corn, sorghum, wheat, barley, and mixed feed from Italy, Spain, Poland, and France were tested for the production of fumonisins B1 and B2 (FB1 and FB2) in corn cultures. All strains of F. moniliforme (1 from France, 10 from Italy, 15 from Poland, and 17 from Spain) and the one tested strain of F. proliferatum produced fumonisins in amounts scattered within a wide range of concentrations (0.7–4100 μg FB1/g). None or insignificant amounts of FB1 were detected in cultures of 11 F. subglutinans strains (<0.5 μg/g for 5 of 11 strains) or in cultures of 3 strains of Fusarium spp. not belonging to Liseola. FB2 was produced by all but one of the strains that produced FB1, and the FB2/FB1 ratio ranged from 0.1 to 0.37 (average, 0.22). The highest production of fumonisin was obtained with isolates from corn (average, 1259 μg FB1/g), followed by isolates from wheat (average, 769 μg FB1/g) and barley (average, 320 μg FB1/g). The production of fumonisins by isolates from sorghum was 2 orders of magnitude lower than corn. These results support data reported for similar surveys in geographical areas other than Europe. In particular, data indicate a situation in Europe that is very similar to North America in respect to fumonisin production by different Fusarium species (F. moniliforme and F. subglutinans) isolated from different substrates (corn and sorghum).

Study of the Reproducibility Characteristics of a Liquid Chromatographic Method for the Determination of Fumonisins B1 and B2 in Corn: IUPAC Collaborative Study

An interlaboratory study of the reproducibility characteristics of a liquid chromatographic method for the determination of fumonisins B1 and B2 in corn was conducted in 11 laboratories in the United States, South Africa, Italy, Japan, United Kingdom, and The Netherlands. Each laboratory was supplied with 12 coded, blind duplicates of 6 samples of naturally contaminated corn containing different amounts of fumonisins B1 and B2 . Samples are extracted with methanol-water (3 + 1), extracts are centrifuged, and supernatants are cleaned up on strong-anion-exchange cartridges, which were supplied to participants. Solutions are derivatized with o-phthaldialdehyde, and individual fumonisins are determined by reversed-phase liquid chromatography with fluorescence detection. Quantitation is by comparison with the supplied fumonisin standards. The within-laboratory repeatability was determined by statistical analysis of data after exclusion of outliers. Relative standard deviations for within-laboratory repeatability varied from 7.7 to 25.5% for fumonisin B1 at concentrations between 200 and 2000 ng/g and from 12.5 to 36.8% for fumonisin B2 at concentrations between 70 and 740 ng/g. Relative standard deviations for betweenlaboratory reproducibility varied from 18.0 to 26.7% for fumonisin B1 and from 28.0 to 45.6% for fumonisin B2 at the concentrations mentioned above. These measures of variability indicate that the method is suitable for adoption as an official method provided that the accuracy characteristics are verified collaboratively.

Liquid Chromatographic Determination of Fumonisins B1, B2, and B3 in Corn: AOAC–IUPAC Collaborative Study

A liquid chromatographic (LC) method for simultaneous determination of fumonisins B1 (FB1), B2 (FB2), and B3 (FB3) in corn was subjected to a collaborative study involving 12 participants from 10 countries, in which the accuracy and reproducibility characteristics of the method were established. Mean analyte recoveries from corn ranged from 81.1 to 84.2% for FB1 (at a spiking range of 500 to 8000 ng/g), from 75.9 to 81.9% for FB2 (at a spiking range of 200 to 3200 ng/g), and from 75.8 to 86.8% for FB3 (at a spiking range of 100 to 1600 ng/g). The valid data were statistically evaluated after exclusion of outliers. Relative standard deviations for within-laboratory repeatability ranged from 5.8 to 13.2% for FB1, from 7.2 to 17.5% for FB2, and from 8.0 to 17.2% for FB3. Relative standard deviations for between-laboratory reproducibility varied from 13.9 to 22.2% for FB1, from 15.8 to 26.7% for FB2, and from 19.5 to 24.9% for FB3. HORRAT ratios, calculated for the individual toxin analogues, ranged from 0.75 to 1.73. The LC method for determination of fumonisins B1, B2, and B3 in corn (at concentrations of 800–12800 ng total fumonisins/g) has been adopted by AOAC INTERNATIONAL.

Reliable Detection of Milk Allergens in Food Using a High-Resolution, Stand-Alone Mass Spectrometer

Reliable methods are needed for detection of allergenic milk proteins in complex food matrixes. The feasibility of an LC/high-resolution MS method for the analysis of milk proteins in a thermally processed model food (incurred cookies) and in white wine spiked, respectively, with milk powder and caseinate is described. Detection of milk proteins was based on the identification of unique peptides in the tryptic digests of cookie/wine extracts using an RP-HPLC separation coupled to an Exactive™ nonhybrid mass spectrometer using Orbitrap technology. The extremely high mass accuracy and resolution provided by the Orbitrap analyzer allowed a fast preliminary identification of four previously proposed peptide markers of caseins using only accurate values of the m/z of their ions. No interference was observed, despite the complexity of the analyzed matrixes. Moreover, the availability of a high- energy, collisionally activated dissociation cell integrated in the mass spectrometer enabled acquisition of peptide MS/MS-like spectra through post-source fragmentation. Confirmation of peptide marker identity could then be achieved by a comparison between experimental and predicted product ions. The described method shows the great potential of Orbitrap MS as a reliable technique in the field of protein allergen detection once the peptide markers are identified.

Determination of Fumonisins B1 and B2 in Corn-Based Foods for Infants and Young Children by LC with Immunoaffinity Column Cleanup: Interlaboratory Validation Study

A liquid chromatographic method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn-based foods for infants and young children was subjected to an interlaboratory validation study involving 11 laboratories. Five blind duplicate sample pairs of each matrix were analyzed to establish the accuracy, repeatability, and reproducibility of the method. Mass fractions in the baby food samples ranged from 89.1 to 384.4 μg/kg FB1 and from 22.5 to 73.6 μg/kg FB2. The method involved a warm extraction with citrate phosphate buffer–methanol–acetonitrile (50 + 25 + 25, v/v/v), a cleanup through an immunoaffinity column, and an end-determination of fumonisins by LC after automated precolumn derivatization with-o-phthaldialdehyde reagent. RSDs for within- laboratory repeatability (RSDr) ranged from 6.8 to 23.5% for FB1 and 7.6 to 22.9% for FB2. RSDs for between-laboratory reproducibility (RSDR) ranged from 15.4 to 26.2% for FB1 and 21.6 to 36.3% for FB2. Mean FB1 recoveries from baby foods spiked at 100.0 and 250.0 μg/kg were 89 and 96%, respectively; for FB2 spiked foods at 25.0 and 62.5 μg/kg recoveries were 90 and 85%, respectively. HorRat values ranged from 0.8 to 1.2 for FB1, whereas for FB2 they ranged from 0.9 to 1.4 when calculated according to Horwitz, and from 1.0 to 1.7 when calculated according to Thompson, indicating an acceptable among- laboratory precision for all matrixes (HorRat values <2).

Immunoaffinity Column Cleanup with Liquid Chromatography Using Post-Column Bromination for Determination of Aflatoxin B1 in Cattle Feed: Collaborative Study

A collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for determination of aflatoxin B1 in cattle feed at a possible future European regulatory limit (1 ng/g). The test portion was extracted with acetone–water (85 + 15), filtered, diluted with water, and applied to an immunoaffinity column. The column was washed with water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. Aflatoxin B1 was separated and determined by reversed-phase liquid chromatography (RP–LC) and detected by fluorescence after post column derivatization (PCD) involving bromination. PCD was achieved with either pyridinium hydrobromide perbromide (PBPB), used by 14 laboratories, or an electrochemical cell and addition of bromide to the mobile phase, used by 7 laboratories. Both derivatization techniques were not significantly different when compared by the t-test; the method was statistically evaluated for all laboratories together (bromination and PBPB). The cattle feed samples, both spiked and naturally contaminatedwithaflatoxinB1, were sent to 21 laboratories in 14 different countries (United States, Japan, and Europe). Test portions were spiked at levels of 1.2 and 3.6 ng/g for aflatoxin B1. Recoveries ranged from 74 to 157%. Based on results for spiked samples (blind pairs at 2 levels) as well as naturally con-taminated samples (blind pairs at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 5.9 to 8.7%. The relative standard deviation for reproducibility (RSDR) ranged from 17.5 to 19.6%. The method showed acceptable within-and between-laboratory precision for this matrix, as evidenced by HORRAT values, at the target levels of determination for aflatoxin B1. No major differences in RSD were observed, showing that the composition of the feeds was not a factor for the samples tested and that the method was applicable for all materials used.

Determination of Ochratoxin A in Wine and Beer by Immunoaffinity Column Cleanup and Liquid Chromatographic Analysis with Fluorometric Detection: Collaborative Study

The accuracy, repeatability, and reproducibility characteristics of a liquid chromatographic method for the determination of ochratoxin A (OTA) in white wine, red wine, and beer were established in a collaborative study involving 18 laboratories in 10 countries. Blind duplicates of blank, spiked, and naturally contaminated materials at levels ranging from ≤0.01 to 3.00 ng/mL were analyzed. Wine and beer samples were diluted with a solution containing polyethylene glycol and sodium hydrogen carbonate, and the diluted samples were filtered and cleaned up on an immunoaffinity column. OTA was eluted with methanol and quantified by reversed-phase liquid chromatography with fluorometric detection. Average recoveries from white wine, red wine, and beer ranged from 88.2 to 105.4% (at spiking levels ranging from 0.1 to 2.0 ng/mL), from 84.3 to 93.1% (at spiking levels ranging from 0.2 to 3.0 ng/mL), and from 87.0 to 95.0% (at spiking levels ranging from 0.2 to 1.5 ng/mL), respectively. Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 6.6 to 10.8% for white wine, from 6.5 to 10.8% for red wine, and from 4.7 to 16.5% for beer. Relative standard deviations for between-laboratories reproducibility (RSDR) ranged from 13.1 to 15.9% for white wine, from 11.9 to 13.6% for red wine, and from 15.2 to 26.1% for beer. HORRAT values were ≤0.4 for the 3 matrixes.

Determination of Fumonisins B1 and B2 in Corn and Corn Flakes by Liquid Chromatography with Immunoaffinity Column Cleanup: Collaborative Study

A liquid chromatographic (LC) method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn and corn flakes was collaboratively studied by 23 laboratories, which analyzed 5 blind duplicate pairs of each matrix to establish the accuracy, repeatability, and reproducibility characteristics of the method. Fumonisin levels in the corn ranged from <0.05 (blank) to 1.41 μg/g for FB1 and from <0.05 to 0.56 μg/g for FB2, whereas in the corn flakes they ranged from <0.05 to 1.05 μg/g for FB1 and from <0.05 to 0.46 μg/g for FB2. The method involved double extraction with acetonitrile–methanol–water (25 + 25 + 50), cleanup through an immunoaffinity column, and LC determination of the fumonisins after derivatization with o-phthaldialdehyde. Relative standard deviations for the within-laboratory repeatability (RSDr) of the corn analyses ranged from 19 to 24% for FB1 and from 19 to 27% for FB2; for the corn flakes analyses, RSDr ranged from 9 to 21% for FB1 and from 8 to 22% for FB2. Relative standard deviations for the between-laboratories reproducibility (RSDR) of the corn analyses ranged from 22 to 28% for FB1 and from 22 to 30% for the FB2; for corn flakes analyses, RSDR ranged from 27 to 32% for FB1 and from 26 to 35% for FB2. Mean recoveries of FB1 and FB2 from corn spiked with FB1 at 0.80 μg/g and with FB2 at 0.40 μg/g were 76 and 72%, respectively; for corn flakes spiked at the same levels recoveries were 110 and 97% for FB1 and FB2, respectively. HORRAT ratios for the analyses of corn ranged from 1.44 to 1.53 for FB1 and from 0.96 to 1.48 for FB2, whereas for corn flakes they ranged from 1.60 to 1.82 for FB1 and from 1.39 to 1.68 for FB2.

A multicenter, observational, prospective study of self- and parent-reported quality of life in adolescent multiple sclerosis patients self-administering interferon-β1a using RebiSmart™-the FUTURE study

Besides the impact of disease per se, the use of immunomodulatory therapies in adolescents with relapsing-remitting multiple sclerosis (RRMS) may have an effect on quality of life (QL). The FUTURE (Quality of liFe in adolescent sUbjecTs affected by mUltiple sclerosis treated with immunomodulatoRy agEnt using self-injecting device) study was designed to evaluate the changes in QL of Italian adolescents with RRMS receiving treatment with IFN-β1a (Rebif; 22 μg), administered subcutaneously three times weekly using the RebiSmart™ electronic autoinjection device over a 52-week period. Fifty adolescents with RRMS were enrolled and 40 completed the study. Changes from baseline to end of treatment (EoT) in adolescent self-reported and parent-reported QL were assessed using the Pediatric Quality of Life Inventory Multidimensional Fatigue Scale (PedsQL), which has been validated for use in pediatric MS and for which an Italian version is available. The adolescent self-reported total PedsQL4.0 score and all of its subscales tended to increase from baseline to EoT, the only exception being "Emotional functioning." In parent-reported measures, the total PedsQL4.0 score increased significantly from baseline to EoT (+ 5.27 points, p = 0.041). Significant increases were also evident for parent-reported "Psychosocial health summary score" (+ 5.90 points; p = 0.015) and "School functioning" (+ 7.84 points; p = 0.029). Our results indicate that adolescents with RRMS using the electronic injection device RebiSmart™ for self-administration of Rebif® can experience long-term improvements in QL.

To d , or not to d : recent developments and comparisons of regularization schemes

We give an introduction to several regularization schemes that deal with ultraviolet and infrared singularities appearing in higher-order computations in quantum field theories. Comparing the computation of simple quantities in the various schemes, we point out similarities and differences between them.

Rapid profiling of antimicrobial compounds characterising B. subtilis TR50 cell-free filtrate by high-performance liquid chromatography coupled to high-resolution Orbitrap™ mass spectrometry

RATIONALE

Several Bacillus strains, typically isolated from different food sources, represent renowned producers of a multitude of low and high molecular weight compounds, including lipopeptides and macrolactones, with an importance for their antimicrobial activity. The high homology shared by many of these compounds also occurring as closely related isoforms poses a challenge in their prompt detection.

METHODS

Identification and structural elucidation is generally achieved by matrix-assisted laser desorption/ionization (MALDI) or liquid chromatography (LC) coupled to mass spectrometry (MS) after a pre-fractionation and/or purification step of the extract. In this paper we report the application of a method based on LC separation and high-resolution Orbitrap™-based MS for the rapid screening of raw filtrate of the strain Bacillus subtilis TR50 endowed with antimicrobial activity, without requiring any sample pre-treatment.

RESULTS

Upon direct analysis of the cell-free filtrate of Bacillus subtilis TR50 by high-resolution mass spectrometry (HRMS), different compounds families, that proved to exert a remarked antimicrobial activity against several foodborne pathogens, can be readily displayed along the chromatographic run. Among them, three different classes were identified and characterized belonging to the iturin, fengycin and surfactin groups. The high resolving power and accurate mass accuracy provided by the HRMS system in use ensured an enhanced selectivity compared to other mass spectrometers. In addition, after activation of the HCD cell, the HR-MS/MS spectra can provide insights in the structural elucidation of several compounds.

CONCLUSIONS

The acquisition of HRMS spectra of raw filtrates of subtilis strains allows untargeted analysis of the major classes of compounds produced to be performed, thus facilitating identification of other unknown bioactive molecules after retrospective analysis. These features make this approach a fast tool applicable to the rapid screening and further identification of antimicrobial compounds released by Bacillus strains in raw filtrates.

Assessment of Mycotoxin Exposure in Côte d'ivoire (Ivory Coast) Through Multi-Biomarker Analysis and Possible Correlation with Food Consumption Patterns

Scope:

The aim of the presented study was to investigate the mycotoxin exposure of Ivorian population related to the consumption patterns of maize, peanuts, millet, and cassava product (attiéké).

Materials and Methods:

Maize flour samples (n = 51) were purchased from all Abidjan local markets, in the south of Ivory Coast, and urine (n = 99) was collected during the same reference period (July–September 2011) from volunteers living in Abidjan and Daloa cities. Reversed-phase liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry (LC-ESI-MS/MS) was used to analyze aflatoxins (AFB₁, AFB₂, AFG₁, and AFG₂), ochratoxin A (OTA), fumonisins (FB₁, FB₂), deoxynivalenol (DON), zearalenone (ZEA), and T-2 and HT-2 toxins in maize flour samples, and their relevant biomarkers (AFM₁, DON, DON + de-epoxydeoxynivalenol (DOM-1), FB₁, α-zearalenol (ZOL), β-ZOL, and OTA) in urine samples.

Results:

Critical maize contamination was observed by AFs occurrence (total AFs 4.5 – 330.0 μg/kg) while OTA was found in 13% of samples analyzed. AFM₁ was detected in 40% of urines samples (0.06 – 14.11 ng/ml), OTA in 37% (0.01 – 0.42 ng/ml), FB₁ in 27% (0.07 to 15.31 ng/ml) and, DON was found in 21% of samples at levels up to 10.0 ng/ml. The correlation coefficients (R²) obtained by plotting the percentage of biomarker occurrence (positive samples) versus the frequency of food consumption revealed maize, peanuts, millet and attiéké were strongly linked to AFB1 and OTA exposure with values of R² ranged from 0.462 to 0.956.

Conclusion:

The present study provided data on mycotoxin risk in Ivory Coast, revealing a frequent co-exposure to the major mycotoxins such as AFs, OTA, and fumonisins, which appeared to be related to the frequency of peanuts, maize, millet and attiéké consumption.

Orbitrap™ monostage MS versus hybrid linear ion trap MS: application to multi-allergen screening in wine

Food allergen research has made giant steps in the last years thanks to the features offered by the latest technology of mass analyzers placed on the market allowing multiplex sensitive detection of proteins. Potentials and features of two mass analyzers namely a linear ion trap capable of performing a data dependent or selected reaction monitoring analysis and an Orbitrap(TM) stand-alone MS enabling a broadband fragmentation without mass selection at highest mass resolving power are herein described and applied to the multiplex screening of allergens in a type of wine chosen as a reference matrix. Quantitative and confirmative capabilities of both platforms were assessed on the specific case study, the multiple detection of egg and milk -related proteins, typically employed in white wines as fining agents. Commercial bioinformatic tools used for a quick allergen identification will be also discussed.

Multi-allergen detection in food by micro high-performance liquid chromatography coupled to a dual cell linear ion trap mass spectrometry

There is a raising demand for sensitive and high throughput MS based methods for screening purposes especially tailored to the detection of allergen contaminants in different food commodities. A challenging issue is represented by complex food matrices where the antibody-based kits commercially available might encounter objective limitations consequently to epitope masking phenomena due to a multitude of interfering compounds arising from the matrix. The performance of a method duly optimized for the extraction and simultaneous detection of soy, egg and milk allergens in a cookie food matrix by microHPLC-ESI-MS/MS, is herein reported. Thanks to the innovative configuration and the versatility shown by the dual cell linear ion trap MS used, the most intense and reliable peptide markers were first identified by untargeted survey experiment, and subsequently employed to design an ad hoc multi-target SRM method, based on the most intense transitions recorded for each selected precursor peptide. A sample extraction and purification protocol was optimized also including an additional step based on sonication, which resulted in a considerable improvement in the detection of milk allergen peptides. Data Dependent™ Acquisition scheme allowed to fill out a tentative list of potential peptide markers, which were further filtered upon fulfilling specific requirements. A total of eleven peptides were monitored simultaneously for confirmation purposes of each allergenic contaminant and the two most sensitive peptide markers/protein were selected in order to retrieve quantitative information. Relevant LODs were found to range from 0.1μg/g for milk to 0.3μg/g for egg and 2μg/g for soy.

Toxic mechanisms induced by fumonisin b1 mycotoxin on human intestinal cell line

The gastrointestinal tract is the main target of exposure to mycotoxin fumonisin B1 (FB1), common natural contaminant in food. Previous studies reported that proliferating cells are more sensitive than confluent cells to the toxic effect of FB1. This study aims to investigate, by dose- and time-dependent experiments on human colon proliferating intestinal cell line (HT-29), the modifications induced by FB1 at concentrations ranging from 0.25 to 69 μM. The choice of highest FB1 concentration considered the low toxicity previously reported on intestinal cell lines, whereas the lowest one corresponded to the lower FBs levels permitted by European Commission Regulation. Different functional parameters were tested such as cell proliferation, oxidative status, immunomodulatory effect and changes in membrane microviscosity. In addition FB1-FITC localization in this cell line was assessed by using confocal laser scanning microscopy. Lipid peroxidation induction was the main and early (12 h) effect induced by FB1 at concentrations ranging from 0.5 to 69 μM, followed by inhibition of cell proliferation (up to 8.6 μM), the immunomodulatory effect (up to 17.2 μM), by assessing IL-8 secretion, and increase in membrane microviscosity (up to 34.5 μM). The toxic effects observed in different functional parameters were not dose-dependent and could be the consequence of the FB1 intracytoplasmatic localization as confirmed by confocal microscopy results. The different timescales and concentrations active of different functional parameters could suggest different cellular targets of FB1.

Pepsin-digested bovine lactoferrin prevents Mozzarella cheese blue discoloration caused by Pseudomonas fluorescens

The aim of this work was to check the efficacy of bovine lactoferrin hydrolyzed by pepsin (LFH) to prevent blue discoloration of Mozzarella cheese delaying the growth of the related spoilage bacteria. Among 64 Pseudomonas fluorescens strains, isolated from 105 Mozzarella samples, only ten developed blue discoloration in cold-stored Mozzarella cheese slices. When Mozzarella cheese samples from dairy were treated with LFH and inoculated with a selected P. fluorescens strain, no pigmentation and changes in casein profiles were found up to 14 days of cold storage. In addition, starting from day 5, the count of P. fluorescens spoiling strain was steadily ca. one log cycle lower than that of LFH-free samples. ESI-Orbitrap-based mass spectrometry analyses allowed to reveal the pigment leucoindigoidine only in the blue LFH-free cheese samples indicating that this compound could be considered a chemical marker of this alteration. For the first time, an innovative mild approach, based on the antimicrobial activity of milk protein hydrolysates, for counteracting blue Mozzarella event and controlling psychrotrophic pigmenting pseudomonads, is here reported.

Improved method for the simultaneous determination of aflatoxins, ochratoxin A and Fusarium toxins in cereals and derived products by liquid chromatography-tandem mass spectrometry after multi-toxin immunoaffinity clean up

An improved method for the quantitative determination of aflatoxins (B1, B2, G1, G2), ochratoxin A, fumonisins (B1, B2), zearalenone, deoxynivalenol, nivalenol, T-2 and HT-2 toxins in cereals and derived products, at levels comparable with EU maximum permitted levels, was developed. The effective co-extraction of the mycotoxins under investigation was achieved in 4min by a double extraction approach, using water followed by methanol. Clean up of the extract was performed by a new multi-toxin immunoaffinity column. Analytical performance characteristics were evaluated through single laboratory validation. Raw wheat and maize, corn flakes and maize snacks were chosen as representative matrices for method validation. The validation assay was carried out at 50, 100 and 150% of EU maximum permitted levels for each mycotoxin. Statistical analysis of the results (ANOVA) provided the within laboratory reproducibility and the error contributions from repeatability, between day effects, and influences from different matrix composition. Recoveries generally higher than 70% were obtained for all tested mycotoxins with relative standard deviation (within laboratory reproducibility) lesser than 37%. Limits of quantification (calculated as the lowest amount of each analyte which could be determined with a precision of 10%) ranged from 1μg/kg to 30μg/kg. The trueness of generated data was assessed by analysis of reference materials. The proposed method was proven to be suitable to assess, with a single analysis, compliance of the selected cereal based foods with the EU maximum permitted or recommended levels for all regulated mycotoxins.

Use of liquid chromatography-high-resolution mass spectrometry for isolation and characterization of hydrolyzed fumonisins and relevant analysis in maize-based products

The synthesis of partially hydrolyzed fumonisins (PHFB1 and PHFB2) and hydrolyzed fumonisins (HFB1 and HFB2) by chemical hydrolysis of pure fumonisins (FB1 and FB2) is reported together with the isolation and characterization by liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Two structural isomers of partially hydrolyzed forms of FB1 and FB2 were identified, namely PHFB(1a) and PHFB(1b) and PHFB(2a) and PHFB(2b). Reaction yields were 21% for PHFB1 (sum of the two isomers), 52% for HFB1, 31% for PHFB2 (sum of the two isomers) and 30% for HFB2. Purity of each isolated compound was >98%. An LC-HRMS method for the simultaneous determination of fumonisins and their partially and totally hydrolyzed derivatives was applied to 24 naturally contaminated samples of maize and maize-based products. The majority of samples (18 out of 24) were contaminated with fumonisins B1 and B2. Fumonisins co-occurred with both partially hydrolyzed and hydrolyzed fumonisins in four nixtamalized samples (three masa flours and one tortilla chips). Co-occurrence of fumonisins with partially hydrolyzed fumonisins was also recorded in one sample of maize kernels and four samples of maize-based products (i.e. maize meal, cous-cous, corn-cakes and cornflakes). Mycotoxins levels ranged from 60 to 5700 µg/kg for fumonisins (sum of FB1 and FB2), from 10 to 210 µg/kg for partially hydrolyzed fumonisins (sum of PHFB1 and PHFB2) and from 30 to 200 µg/kg for hydrolyzed fumonisins (sum of HFB1 and HFB2). This is the first report of the isolation of PHFB2 and the co-occurrence of FB1, FB2, PHFB1, PHFB2, HFB1 and HFB2 in maize products. Considering the growing use of nixtamalized and maize-based products, the monitoring of fumonisins and their partially and totally hydrolyzed forms in these products may represent an important contributing factor in evaluating the relevant human risk exposure.

Influence on functional parameters of intestinal tract induced by short-term exposure to fumonisins contaminated corn chyme samples

The gut is a possible target toward mycotoxin fumonisins (FBs) exposure. The study aims to investigate the effects induced by FBs contaminated-corn chyme samples on functional parameters of human and rat intestine by using Ussing chamber. Fumonisins-contaminated corn and processed corn samples were undergone to in vitro digestion process and then added to luminal side. A reduction (about 90%) of short circuit current (Isc μA/cm(2)) during exposure of human colon tissues to fumonisins-free corn chyme samples was observed, probably related to increased chyme osmolality. This hyperosmotic stress could drain water towards the luminal compartment, modifying Na(+) and Cl(-) transports. The presence of FBs in corn chyme samples, independently to their concentration, did not affect significantly the Isc, probably related to their interference towards epithelial Na(+) transport, as assessed by using a specific inhibitor (Amiloride). The rat colon tract represents a more accessible model to study FBs toxicity showing a similar functional response to human. In the rat small intestine a significant reduction (about 15%) of Isc parameter during exposure to uncontaminated or FBs contaminated corn chyme samples was observed; therefore such model was not suitable to assess the FBs toxicity, probably because the prevalent glucose and amino acids electrogenic absorption overwhelmed the FBs influence on ionic transport.

Assessment of multi-mycotoxin exposure in southern Italy by urinary multi-biomarker determination

Human exposure assessment to deoxynivalenol (DON), aflatoxin B1 (AFB1), fumonisin B1 (FB1), zearalenone (ZEA) and ochratoxin A (OTA) can be performed by measuring their urinary biomarkers. Suitable biomarkers of exposure for these mycotoxins are DON + de-epoxydeoxynivalenol (DOM-1), aflatoxin M1 (AFM1), FB₁, ZEA + α-zearalenol (α-ZOL) + β-zearalenol (β-ZOL) and OTA, respectively. An UPLC-MS/MS multi-biomarker method was used to detect and measure incidence and levels of these biomarkers in urine samples of 52 volunteers resident in Apulia region in Southern Italy. The presence of ZEA + ZOLs, OTA, DON, FB1 and AFM1 were detected in 100%, 100%, 96%, 56% and 6%, of samples, respectively. All samples contained biomarkers of two or more mycotoxins. The mean concentrations of biomarkers ranged from 0.055 ng/mL (FB1) to 11.89 ng/mL (DON). Urinary biomarker concentrations were used to estimate human exposure to multiple mycotoxin. For OTA and DON, 94% and 40% of volunteers, respectively exceeded the tolerable daily intake (TDI) for these mycotoxins. The estimated human exposure to FB1 and ZEA was largely below the TDI for these mycotoxins for all volunteers.

Assessment of multi-mycotoxin adsorption efficacy of grape pomace

Grape pomace (pulp and skins) was investigated as a new biosorbent for removing mycotoxins from liquid media. In vitro adsorption experiments showed that the pomace obtained from Primitivo grapes is able to sequester rapidly and simultaneously different mycotoxins. Aflatoxin B1 (AFB1) was the most adsorbed mycotoxin followed by zearalenone (ZEA), ochratoxin A (OTA), and fumonisin B1 (FB1), whereas the adsorption of deoxynivalenol (DON) was negligible. AFB1 and ZEA adsorptions were not affected by changing pH values in the pH 3-8 range, whereas OTA and FB1 adsorptions were significantly affected by pH. Equilibrium adsorption isotherms obtained at different temperatures (5-70 °C) and pH values (3 and 7) were modeled and evaluated using the Freundlich, Langmuir, Sips, and Hill models. The goodness of the fits and the parameters involved in the adsorption mechanism were calculated by the nonlinear regression analysis method. The best-fitting models to describe AFB1, ZEA, and OTA adsorption by grape pomace were the Sips, Langmuir, and Freundlich models, respectively. The Langmuir and Sips models were the best models for FB1 adsorption at pH 7 and 3, respectively. The theoretical maximum adsorption capacities (mmol/kg dried pomace) calculated at pH 7 and 3 decreased in the following order: AFB1 (15.0 and 15.1) > ZEA (8.6 and 8.3) > OTA (6.3-6.9) > FB1 (2.2 and 0.4). Single- and multi-mycotoxin adsorption isotherms showed that toxin adsorption is not affected by the simultaneous presence of different mycotoxins in the liquid medium. The profiles of adsorption isotherms obtained at different temperatures and pH and the thermodynamic parameters (ΔG°, ΔH°, ΔS°) suggest that mycotoxin adsorption is an exothermic and spontaneous process, which involves physisorption weak associations. Hydrophobic interactions may be associated with AFB1 and ZEA adsorption, whereas polar noncovalent interactions may be associated with OTA and FB1 adsorption. In conclusion, this study suggests that biosorption of mycotoxins onto grape pomace may be a reasonably low-cost decontamination method.

Mycotoxin profile of Fusarium langsethiae isolated from wheat in Italy: production of type-A trichothecenes and relevant glucosyl derivatives

Fusarium langsethiae, formally described as a new species over a decade ago, has been identified as the main producer of HT-2 (HT2) and T-2 (T2) toxins in Europe in small cereal grains. Mycotoxin contamination caused by this Fusarium species can represent a food safety hazard that deserves further attention. In the present work, the mycotoxin profile in wheat cultures of F. langsethiae is presented with particular reference to the production of major type-A trichothecenes and their glucosyl derivatives. F. langsethiae isolates, representative of the major Italian wheat cultivation areas, were tested for the production of T2, HT2, diacetoxyscirpenol (DAS) and neosolaniol (NEO), and relevant glucosyl derivatives. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for the identification and chemical characterization of these metabolites. F. langsethiae isolates under investigation resulted to be potent producers of T2, HT2 and NEO. Furthermore, a well-defined set of isolates, all originating from Central Italy, produced also DAS. All isolates were found to be able to produce HT2 glucosyl derivatives, whereas only traces of T2 glucoside were detected in one sample. Furthermore, two mono-glucosyl derivatives of NEO and one mono-glucoside derivative of DAS were identified and characterized. The screening for the presence/absence of glucosylated trichothecenes in analyzed fungal extracts revealed a general co-occurrence of these derivatives with the parent toxin at levels that could be roughly estimated to account up to 37% of the relevant unconjugated toxin. This is the first report of the production of glucosylated trichothecenes by F. langsethiae cultured on small grains.

Multi-allergen quantification of fining-related egg and milk proteins in white wines by high-resolution mass spectrometry

RATIONALE

A method based on High-Resolution Mass Spectrometry was developed for the simultaneous determination of fining agents containing potentially allergenic milk (casein) and egg-white (lysozyme and ovalbumin) proteins, added to commercial white wines at sub-ppm levels. Selected tryptic peptides were used as quantitative markers. An evaluation of protein digestion yields was also performed by implementing the (15)N-valine-labelled analogues of the best peptide markers identified for αS1 -casein and ovalbumin.

METHODS

The method was based on the combination of ultrafiltration (UF) of protein-containing wines, tryptic digestion of the dialyzed wine extracts and liquid chromatography/high resolution mass spectrometry (LC/HRMS) analysis of tryptic digests. Peptides providing the most intense electrospray ionization (ESI)-MS response were chosen as quantitative markers of the proteins under investigation.

RESULTS

Six-point calibrations were performed by adding caseinate and egg-white powder in the concentration range between 0.25 and 10 µg/mL, to an allergen-free white wine. The following three peptide markers, LTEWTSSNVMEER, GGLEPINFQTAADQAR and ELINSWVESQTNGIIR, were highlighted as best markers for ovalbumin, while GTDVQAWIR and NTDGSTDYGILQINSR for lysozyme and YLGYLEQLLR, GPFPIIV and FFVAPFPEVFGK for caseinate. Limits of detection (LODs) ranged from 0.4 to 1.1 µg/mL.

CONCLUSIONS

The developed method is suited for assessing the contemporary presence of allergenic milk and egg proteins characterizing egg white and caseinate, fining agents typically employed for wine clarification. The LODs of the method enable the detection of sub-ppm concentrations of residual fining agents, that could represent a potential risk for allergic consumers.

Mycological analysis and multimycotoxins in maize from rural subsistence farmers in the former Transkei, South Africa

Maize harvested in the Centane region of the former Transkei, Eastern Cape Province, South Africa, by subsistence farmers has been shown over many seasons to be contaminated with fumonisin mycotoxins. However, there are limited data on the presence of other mycotoxins. Two multimycotoxin LC-MS/MS methods were applied to good and moldy maize samples, as separated by the farmers themselves from the 2011 harvest. One method involved extract cleanup on multitoxin immunoaffinity columns before LC-MS/MS analysis for aflatoxins, fumonisins, deoxynivalenol (DON), zearalenone (ZEN), and T-2 and HT-2 toxins. The other method was based on a "dilute-and-shoot" approach for the above mycotoxins and a wide range of other fungal secondary metabolites. Both methods showed high incidences of fumonisins B1 and B2 (FB1 and FB2) in good maize (100% for both by the first method, means were 2083 and 927 μg/kg for the two analogues; 93% for both by the second method, positive means of 2764 and 1050 μg/kg, respectively). All samples of moldy maize were contaminated (mean FB1 of 27.64 and 35.98 mg/kg, respectively; mean FB2 of 10.58 and 14.14 mg/kg, respectively). Comparison of the two methods for FB1 and FB2 over the entire range of samples gave R(2) values 0.9144 and 0.8859, respectively. Low levels of DON were found by both methods (positive means of 12 and 4.7 μg/kg in good maize, respectively, and of 14 and 5.8 μg/kg in moldy maize, respectively). ZEN was determined with positive means of 108 and 25 μg/kg in good maize, respectively, and of 111 and 135 μg/kg in moldy maize, respectively. No aflatoxins, OTA, or T-2 or HT-2 toxins were detected. A wide range of other Fusarium , Aspergillus , Alternaria , and Penicillium mycotoxins and secondary metabolites were determined.

Multiple mycotoxin exposure determined by urinary biomarkers in rural subsistence farmers in the former Transkei, South Africa

Subsistence farmers are exposed to a range of mycotoxins. This study applied novel urinary multi-mycotoxin LC-MS/MS methods to determine multiple exposure biomarkers in the high oesophageal cancer region, Transkei, South Africa. Fifty-three female participants donated part of their maize-based evening meal and first void morning urine, which was analysed both with sample clean-up (single and multi-biomarker) and by a 'dilute-and-shoot' multi-biomarker method. Results were corrected for recovery with LOD for not detected. A single biomarker method detected fumonisin B1 (FB1) (87% incidence; mean±standard deviation 0.342±0.466 ng/mg creatinine) and deoxynivalenol (100%; mean 20.4±49.4 ng/mg creatinine) after hydrolysis with β-glucuronidase. The multi-biomarker 'dilute-and-shoot' method indicated deoxynivalenol-15-glucuronide was predominantly present. A multi-biomarker method with β-glucuronidase and immunoaffinity clean-up determined zearalenone (100%; 0.529±1.60 ng/mg creatinine), FB1 (96%; 1.52±2.17 ng/mg creatinine), α-zearalenol (92%; 0.614±1.91 ng/mg creatinine), deoxynivalenol (87%; 11.3±27.1 ng/mg creatinine), β-zearalenol (75%; 0.702±2.95 ng/mg creatinine) and ochratoxin A (98%; 0.041±0.086 ng/mg creatinine). These demonstrate the value of multi-biomarker methods in measuring exposures in populations exposed to multiple mycotoxins. This is the first finding of urinary deoxynivalenol, zearalenone, their conjugates, ochratoxin A and zearalenols in Transkei.

Critical evaluation of LC-MS-based methods for simultaneous determination of deoxynivalenol, ochratoxin A, zearalenone, aflatoxins, fumonisins and T-2/HT-2 toxins in maize

The results of a proficiency test for the LC-MS/(MS) determination of up to 11 mycotoxins (aflatoxins B1, B2, G1 and G2, fumonisins B1 and B2, ochratoxin A, deoxynivalenol, T-2 and HT-2 toxins and zearalenone) in maize were evaluated to identify possible strengths and weaknesses of various methodologies used by the 41 participating laboratories. The majority of laboratories (56%) used mixtures of acetonitrile:water for extraction. Other laboratories used methanol:water mixtures (17%) or performed two consecutive extractions with phosphate buffer solution (PBS) followed by methanol (15%). Few laboratories used mixtures of acetonitrile:water:methanol (7%), water:ethyl acetate (2.5%) or PBS alone (2.5%). The majority of laboratories (58%) used a clean-up step prior to chromatography. The remaining laboratories analysed crude extracts (37%) or used a mixed approach (5%). The amount of sample equivalent injected into LC-MS/(MS) ranged between 0.1-303 mg for purified extracts and 0.08-20 mg for directly analysed crude extracts. External (54%), matrix-matched (22%) or stable isotope-labelled internal standards calibration (24%) were used for toxin quantification. In general, extraction mixtures of water with acetonitrile, methanol or both provided good results for quantitative extraction of mycotoxins from maize. Laboratories using sample extract clean-up reported acceptable results for the majority of mycotoxins. Good results were also obtained by laboratories that analysed crude extracts although a high variability of results was observed for all tested mycotoxins. Matrix-matched calibration or isotope-labelled internal standards efficiently compensated matrix effects whereas external calibration gave reliable results by injecting ≤10 mg of matrix equivalent amounts. Unacceptable high recovery and high variability of fumonisin results were obtained by the majority of laboratories, which could not be explained and thus require further investigation. These findings provide the basis for the optimization and selection of methods to be used in future interlaboratory validation studies to derive their performance characteristics for simultaneous determination of mycotoxins in maize.

Validation study on urinary biomarkers of exposure for aflatoxin B1, ochratoxin A, fumonisin B1, deoxynivalenol and zearalenone in piglets

The multi-biomarker approach was used to validate urinary biomarkers in piglets administered boluses contaminated with mixtures of deoxynivalenol (DON), aflatoxin B1 (AFB1), fumonisin B1 (FB1), zearalenone (ZEA) and ochratoxin A (OTA) at different concentrations. Boluses contaminated with mycotoxins were prepared by slurrying and freezedrying feed material fortified with culture extracts of selected toxigenic fungi. Piglets were individually placed in metabolic cages to collect urine before gavage and 24 h post dose. Urine samples were hydrolysed with β-glucuronidase and analysed by a multi-biomarker LC-MS/MS method developed and validated to identify and measure biomarkers of FB1, OTA, DON, ZEA and AFB1. Urinary levels of FB1, OTA, DON + de-epoxy-deoxynivalenol, ZEA + alphazearalenol and aflatoxin M1 were selected as biomarkers of FB1, OTA, DON, ZEA and AFB1, respectively. Mean percentages of dietary mycotoxins excreted as biomarkers in 24 h post dose urine were 36.8% for ZEA, 28.5% for DON, 2.6% FB1, 2.6% for OTA and 2.5% for AFB1. A good correlation was observed between the amount of mycotoxins ingested and the amount of relevant biomarkers excreted in 24 h post dose urine. Linear dose-response correlation coefficients ranged between 0.68 and 0.78 for the tested couples of mycotoxin/biomarker. The good sensitivity of the LC-MS/MS method and the good dose-response correlations observed in this study permitted to validate the selected mycotoxin biomarkers in piglets at dietary levels close to the maximum permitted levels reported in Commission Directive 2003/100/EC for AFB1 and the guidance values reported in Commission Recommendation 2006/576/EC for DON, ZEA, OTA and FB1.

Trichothecene mycotoxins in kernels and head fusariosis susceptibility in winter triticale

A single isolates ofFusarium graminearum Schwabe KF 366 andFusarium culmorum (W.G.Sm.) Sacc. KF 365 were used to infect 10 genotypes (9 lines and one cultivar) of winter triticale, 1 rye cultivar and 1 wheat cultivar, and amounts of mycotoxins in kernels were analysed at the same stage of development. One genotype of triticale CHD 353/79 and rye "Chodan" were found to be most resistant towards both species infection with lowest amount of mycotoxins (deoxynivalenol) content in kernels and also the lowest yield reduction. The most susceptible line CZR 142 cumulated in kernels about ten times higher amount of mycotoxins (up 53 mg DON/kg and 16 mg 3AcDON/kg, and 5 mg zearalenone/kg). GenerallyF, culmorum formed higher level of mycotoxins in kernels of infected heads thanF. graminearum. In kernels of more susceptible genotypes except deoxynivalenol, 3 acetyldeoxynivalenol and zearalenone also were present.

Experimental design for in-house validation of a screening immunoassay kit. The case of a multiplex dipstick for Fusarium mycotoxins in cereals

The benefits of using rapid qualitative methods to verify compliance of food and feed with legislation requirements include user-friendly format, the possibility of detection without expensive instrumentation, rapid response and affordable price. Prior to their use, however, the methods have to pass validation experiments, in order to assess their performance profile. An experimental protocol for in-house validation of a screening immunoassay has been designed and applied to evaluate performance characteristics of a multiplex dipstick kit for the determination of major Fusarium toxins, namely zearalenone, T-2 and HT-2 toxins, deoxynivalenol and fumonisins in wheat and maize. The test is intended for screening of cereals on the presence/absence of these mycotoxins at maximum permitted levels established by European legislation or target levels. The response of the measurement is determined with a reader device. Samples classified as negative are considered as compliant, whereas positive samples need to be re-analysed with confirmatory methods. The in-house validation design consisted of three steps, namely (1) estimating the precision of the method including "between day" effects and influences from different varieties of the matrices, (2) establishing robust cutoff values for the dipstick response at target mycotoxin levels assuming an acceptable rate of false negative results of 5% and (3) assessment of the rate of false positive results of blank samples and samples containing the target analytes below the legal limits. The total precision expressed as relative standard deviation and determined individually for each analyte/concentration/matrix combination varied from 9 to 30% and was considered as acceptable. In 17 out of 28 cases, the repeatability standard deviation was the most important factor. The predominance of the repeatability compared to the other factors (matrix, days) was an indicator for the ruggedness of the assay. The validation study demonstrated that the test was able to differentiate blank samples from samples contaminated at target mycotoxin levels with a false positive rate lower than 6%. Considering realistic mycotoxin occurrence in European samples, significant economical benefits can be expected when using the test under real-world conditions.

Determination of ochratoxin A in wine by means of immunoaffinity and aminopropyl solid-phase column cleanup and fluorometric detection

A new analytical method for the determination of ochratoxin A (OTA) in red wine has been developed by using a double-extract cleanup and a fluorometric measurement after spectral deconvolution. Wine samples were diluted with a solution containing 1% polyethylene glycol and 5% sodium hydrogencarbonate, filtered, and purified by immunoaffinity and aminopropyl solid-phase column. OTA contents in the purified extract were determined by a spectrofluorometer (excitation wavelength, 330 nm; emission wavelength, 470 nm) after deconvolution of fluorescence spectra. Average recoveries from wine samples spiked with OTA at levels ranging from 0.5 to 3.0 ng/mL were 94.5-105.4% with relative standard deviations (RSD) of <15% (n = 4). The limit of detection (LOD) was 0.2 ng/mL, and the total time of analysis was 30 min. The developed method was tested on 18 red wine samples (naturally contaminated and spiked with OTA at levels ranging from 0.4 to 3.0 ng/mL) and compared with AOAC Official Method 2001.01, based on immunoaffinity column cleanup and HPLC with fluorescence detector. A good correlation (r(2) = 0.9765) was observed between OTA levels obtained with the two methods, highlighting the reliability of the proposed method, the main advantage of which is the simple OTA determination by a benchtop fluorometer with evident reductions of cost and time of analysis.