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 Aflatoxin B1 in Baby Food (Infant Formula) by Immunoaffinity Column Cleanup Liquid Chromatography with Postcolumn Bromination: 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 a milk powder based infant formula at a possible future European regulatory limit (0.1 ng/g). The test portion was extracted with methanol–water (8 + 2 [v + v]), 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. The separation and determination of the aflatoxin B1 was performed by reversed-phase LC and detected by fluorescence after postcolumn derivatization (PCD) involving bromination. PCD was achieved with either pyridinum hydrobromide perbromide (PBPB) or an electrochemical (Kobra) cell by addition of bromide to the mobile phase. The baby food (infant formula) test samples, both spiked and naturally contaminated with aflatoxin B1, were sent to 14 laboratories in 13 different European countries. Test portions were spiked at levels of 0.1 and 0.2 ng/g for aflatoxin B1. Recoveries ranged from 101 to 92%. Based on results for spiked test samples (blind pairs at 2 levels) and naturally contaminated test samples (blind pairs at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 3.5 to 14%. The relative standard deviation for reproducibility (RSDR) ranged from 9 to 23%. Nine participants used PBPB derivatization, and 5 particpants used the Kobra cell. There was no evidence of method performance depending on the derivatization method used. The method showed acceptable within- and between-laboratory precision for baby food matrix, as evidenced by HORRAT values, at the target levels of determination for aflatoxin B1.

Developments in mycotoxin analysis: an update for 2015-2016

This review summarises developments in the determination of mycotoxins over a period between mid-2015 and mid-2016. Analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are methods used to analyse botanicals and spices and newly developed liquid chromatography mass spectrometry based multi-mycotoxin methods. This critical review aims to briefly discuss the most important recent developments and trends in mycotoxin determination as well as to address limitations of presented methodologies.

Aflatoxin B1 contamination in maize in Europe increases due to climate change

Climate change has been reported as a driver for emerging food and feed safety issues worldwide and its expected impact on the presence of mycotoxins in food and feed is of great concern. Aflatoxins have the highest acute and chronic toxicity of all mycotoxins; hence, the maximal concentration in agricultural food and feed products and their commodities is regulated worldwide. The possible change in patterns of aflatoxin occurrence in crops due to climate change is a matter of concern that may require anticipatory actions. The aim of this study was to predict aflatoxin contamination in maize and wheat crops, within the next 100 years, under a +2 °C and +5 °C climate change scenario, applying a modelling approach. Europe was virtually covered by a net, 50 × 50 km grids, identifying 2254 meshes with a central point each. Climate data were generated for each point, linked to predictive models and predictions were run consequently. Aflatoxin B₁ is predicted to become a food safety issue in maize in Europe, especially in the +2 °C scenario, the most probable scenario of climate change expected for the next years. These results represent a supporting tool to reinforce aflatoxin management and to prevent human and animal exposure.

Developments in mycotoxin analysis: an update for 2014-2015

This review summarises developments in the determination of mycotoxins over a period between mid-2014 and mid-2015. In tradition with previous articles of this series, analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are new methods used to analyse botanicals and spices and newly developed LC-MS based multi-mycotoxin methods. The critical review aims to briefly discuss the most important developments and trends in mycotoxin determination as well as to address shortcomings of current methodologies.

Developments in mycotoxin analysis: an update for 2013-2014

This review highlights developments in the determination of mycotoxins over a period between mid-2013 and mid-2014. It continues in the format of the previous articles of this series, emphasising on analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone. The importance of proper sampling and sample preparation is briefly addressed in a dedicated section, while another chapter summarises new methods used to analyse botanicals and spices. As LC-MS/MS instruments are becoming more and more widespread in the determination of multiple classes of mycotoxins, another section is focusing on such newly developed multi-mycotoxin methods. While the wealth of published methods during the 12 month time span makes it impossible to cover every single one, this exhaustive review nevertheless aims to address and briefly discuss the most important developments and trends.

Exposure assessment to mycotoxins in gluten-free diet for celiac patients

Mycotoxins are low molecular weight secondary metabolites produced by certain strains of filamentous fungi such as Aspergillus, Penicillium and Fusarium, which attack crops in the field, and grow on foods also during storage under favorable conditions of temperature and humidity. Foods mainly contributing to the intake of mycotoxins with diet are cereals, maize being the most risky commodity due to the potential co-occurrence of more than one mycotoxin, this can be of particular concern especially for vulnerable group of population such as celiac patients that show increased maize-based products consumption. In this study the exposure of celiac patients to fumonisins (FBs) and zearalenone (ZON) has been assessed. The higher exposures, for all the matrices and for both the selected mycotoxins, were for children age group. The lower and upper bound exposure ranged between 348-582 ng/kg bw/day for FBs and 22-83 ng/kg bw/day for ZON; these values result well below the TDI for the selected mycotoxins, representing the 17-29% and 9-33% of the TDI set for FBs and ZON, respectively. Even considering the worst scenario the exposure values reported for children were lower, namely 1385 ng/kg bw/day for FBs and 237 ng/kg bw/day for ZON, than the corresponding toxicological thresholds.

The role of sampling in mycotoxin contamination: an holistic view

The need to obtain a representative sample deserves particular consideration since a wrong sampling plan can greatly affect the reliability of the measured levels of mycotoxins. This can even result in legal disputes and barriers to trade. Reported here is an holistic view for an ideal sampling plan, which is based on two consecutive steps: (i) To establish 'why, where and when' sampling has to be performed by assessing the purpose, the appropriate time and the site for collecting the samples; (ii) To establish 'how' to draw samples by assessing practical ad hoc guidelines, considering that, for bulk goods in particular, mycotoxins are not at all homogeneously distributed in a lot. So far, step 1 is not yet covered by specific guidelines while for step 2, European regulations establish the procedures for the sampling of bulk and retail products potentially contaminated by mycotoxins.

Detection and traceability of genetically modified organisms in the food production chain

Both labelling and traceability of genetically modified organisms are current issues that are considered in trade and regulation. Currently, labelling of genetically modified foods containing detectable transgenic material is required by EU legislation. A proposed package of legislation would extend this labelling to foods without any traces of transgenics. These new legislations would also impose labelling and a traceability system based on documentation throughout the food and feed manufacture system. The regulatory issues of risk analysis and labelling are currently harmonised by Codex Alimentarius. The implementation and maintenance of the regulations necessitates sampling protocols and analytical methodologies that allow for accurate determination of the content of genetically modified organisms within a food and feed sample. Current methodologies for the analysis of genetically modified organisms are focused on either one of two targets, the transgenic DNA inserted- or the novel protein(s) expressed- in a genetically modified product. For most DNA-based detection methods, the polymerase chain reaction is employed. Items that need consideration in the use of DNA-based detection methods include the specificity, sensitivity, matrix effects, internal reference DNA, availability of external reference materials, hemizygosity versus homozygosity, extrachromosomal DNA, and international harmonisation. For most protein-based methods, enzyme-linked immunosorbent assays with antibodies binding the novel protein are employed. Consideration should be given to the selection of the antigen bound by the antibody, accuracy, validation, and matrix effects. Currently, validation of detection methods for analysis of genetically modified organisms is taking place. In addition, new methodologies are developed, including the use of microarrays, mass spectrometry, and surface plasmon resonance. Challenges for GMO detection include the detection of transgenic material in materials with varying chromosome numbers. The existing and proposed regulatory EU requirements for traceability of genetically modified products fit within a broader tendency towards traceability of foods in general and, commercially, towards products that can be distinguished from each other. Traceability systems document the history of a product and may serve the purpose of both marketing and health protection. In this framework, segregation and identity preservation systems allow for the separation of genetically modified and non-modified products from "farm to fork". Implementation of these systems comes with specific technical requirements for each particular step of the food processing chain. In addition, the feasibility of traceability systems depends on a number of factors, including unique identifiers for each genetically modified product, detection methods, permissible levels of contamination, and financial costs. In conclusion, progress has been achieved in the field of sampling, detection, and traceability of genetically modified products, while some issues remain to be solved. For success, much will depend on the threshold level for adventitious contamination set by legislation.

Serum levels of ochratoxin A in healthy adults in Tuscany: correlation with individual characteristics and between repeat measurements

Ochratoxin A (OTA), a mycotoxin widely contaminating staple foods and beverages, has been classified as a "possible human carcinogen (Group 2B)" by the IARC. Serum levels of OTA were measured in a group of 138 healthy adults (age, 35-65 years) living in the area surrounding Florence (Tuscany, central Italy) and detected in all but four samples (97%). After the exclusion of one subject with a peak value of 57.2 ng/ml, OTA levels ranged between 0.12 and 2.84 ng/ml, with mean and median values of 0.56 and 0.48 ng/ml, respectively. OTA levels were significantly higher in men than in women (0.64 versus 0.50) and correlated positively with height. A strong association was found with the season in which blood samples were obtained, with summer values higher than autumn values. On the other hand, OTA levels tended to be negatively associated with blood pressure, either systolic or diastolic; no association was evident with age, weight, body mass index, and smoking history. The associations with height and season persisted in a multivariate regression analysis. A subgroup of subjects provided a repeat blood sample approximately 1 year later. The Spearman correlation coefficient between 68 pairs of original and repeat measurements was practically null (r = 0.05). Only two subjects (2.9%) had OTA levels of >1 ng/ml on both occasions. These results suggest that OTA contamination is widespread in foods consumed by this population, in agreement with previous reports from Italy and other countries. A strong seasonal variation, which possibly differs from year to year, was observed. OTA serum levels are a short-term biomarker with a high within-subject variability; therefore they have limited use at the individual level but can be used to characterize populations or subgroups of subjects. Additional analyses are needed to explore the dietary determinants of OTA levels in this population.

Application of Biomarkers to Assessment of Risk to Human Health from Exposure to Mycotoxins

Mycotoxins, the toxic compounds produced by mold secondary metabolism, represent a relevant source of danger to humans through alimentary channels. Efforts have been made by researchers and by national authorities to assess mycotoxin incidence in food, but often results are to be considered approximate or inaccurate due to the huge difficulties posed by sampling procedures. More recently the evaluation of mycotoxins in biological fluids have been given increasing attention since the results may offer valuable indications, although general on the overall status of mycotoxin contamination in food and feed. The assessment of the degree of exposure to these contaminants in the population or in specific groups can also be pursued. Researches on mycotoxins in biological fluids greatly contribute to clarify the mechanism of health impairment attributable to these toxic compounds and to elucidate the dose-response relationship. Despite the considerable efforts devoted to mycotoxin research in the past few decades, improvements in methodology has to be achieved mainly in sampling procedures and in quality assurance of the laboratories involved in mycotoxin analysis, as well as in the selection of appropriate biomarkers.

Quality Assurance in Mycotoxin Analysis

Mycotoxin analysis in food and biological fluids is receiving more and more concern, in view also of increasing involvement by the European Union regarding legislation. Basically all the analytical steps regarding mycotoxin analysis have to be performed according to accurate criteria which are strictly connected to the quality of results in terms of reliability. The only rationale for reducing this difficulty is to apply quality assurance principles. Quality assurance principles define, in fact, the rules to be observed for performing this analysis with a degree of uncertainty that is as low as may be possible. In particular sampling techniques, if carried out improperly, give rise to uncertainty concerning the representativeness of samples that is so critical as to induce a dramatic source of errors in the final analysis. Therefore it seems appropriate to plan training courses for personnel on the various side-effects related to the available sampling and subsampling techniques depending on the commodity. Other contributions to the overall error derive from improper methodologies used by technicians in the pre-treatment step of the samples (incorrect use of glassware, standard solutions, etc.), and finally from the operations involved in the whole analytical procedure. In addition, the use of reference materials and certified reference materials together with the utilization of validated methods of analysis will be dealt with as concrete procedures for obtaining the certainty of final results of good quality. This aspect takes on a relevant outcome if applied to official control activities from authorized bodies acting at a national level.

Evaluation of ochratoxin A level in human milk in Italy

In order to estimate the incidence of ochratoxin A (OA) in biological fluids, a study was carried out to determine the concentration of OA in breast milk of donor mothers in Italy. Out of 111 samples, 22 were contaminated in the range 0.1-12 micrograms/kg.

Ochratoxin A levels in human milk and related food samples: an exposure assessment

Ochratoxin A (OA) is a mycotoxin detected in a variety of food and feeds mostly from countries with temperate or continental climate, because the fungi that produce it, mainly Aspergillus ochraceus, Penicillium verrucosum, and Penicillium viridicatum, can grow under a great variety of climate conditions. The aim of this article was, firstly, to confirm the occurrence of OA in human milk in Italy. Then, a preliminary calculation of OA intake via human milk was made, from ingested food. For this investigation, food and milk samples were collected, continuously for a week, from 4 lactating mothers. The obtained results revealed a significant exposure of sucklings and mothers to OA levels higher than the tolerable daily intake as estimated from animal models. On the basis of these data, a major effort in planning surveillance and research programs to control OA contamination in food, feed, and biological fluids should be pursued.

A study of the contamination by ochratoxin A of green and roasted coffee beans

A study was performed to evaluate the contamination by ochratoxin A in coffee beans. Twenty-nine samples of green coffee were collected from large lots of material by representative sampling. The analyses of green coffee samples showed a significantly high contamination percentage (58%) ranging from 0.2 to 15 micrograms/kg. Naturally and artificially contaminated samples were roasted at different operation times (5-6 min) to verify the percentage of destruction of the mycotoxin. The percentage ranged from 48% to 87% and from 90% to 100% in artificially and naturally contaminated samples respectively. The beverages prepared from artificially contaminated coffee using the most common types of coffee makers showed no residues of ochratoxin A.

[Polyfructosan and para-aminohippuric acid clearance, comparison of 2 methods for determining glomerular filtration and plasma renal flow]

Glomerular Filtration Rate (GFR) and Renal Plasma Flow (RPF) were measured respectively, Polyfructosan and Para-aminohippuric acid clearances, in 13 patients with different degrees of renal insufficiency. Two different methods were used, the standard method and one without urine collection. The mean GFR (66.4 +/- 27.8 vs. 72.2 +/- 19.0 ml/m, r = 0.74) and RPF (431 +/- 204 vs 490 +/- 188 ml/m, r = 0.76) as well as Filtration Fraction (17.7 +/- 8.3 vs. 16.6 +/- 6.6%) were well correlated. These data show that within the normal range of GRF and RPF the method determining only plasma levels is as reliable as the standard method, giving the advantage to be less troublesome for patients and staff, requiring no bladder catheterization.

Long-term administration of low doses of mycotoxins to poultry. 1. Residues of aflatoxin B1 and its metabolites in broilers and laying hens

A study was performed to determine aflatoxin residues in tissues and organs of male broilers and hens that had been fed a diet contaminated with 50 micrograms/kg aflatoxin B1 (AFB1). Residue levels of AFB1, aflatoxicol (Ro), aflatoxin M1 (AFM1) and aflatoxin B2a (AFB2a) were determined by an HPLC method and, with the exception of AFB2a, were detected in the liver, kidney and thigh of both male broilers and hens. The highest levels found were for Ro in liver (1.10 and 0.60 micrograms/kg for male broilers and hens, respectively). On the other hand no detectable amounts of aflatoxins were found in any tissue after withdrawal periods of 14 and 33 days for male broilers and laying hens respectively.

Evaluation of lead, cadmium, chromium, copper and zinc by atomic absorption spectroscopy in durum wheat milling products in relation to the percentage of extraction

36 samples representative of the 1981 Italian durum wheat crop were separated by an industrial Italian milling process and the products obtained analyzed by AAS for their Pb, Cd, Cr, Cu, Zn content. The results obtained were: Pb ranging from 0.04 to 0.80 ppm, Cd from 0.02 to 1.39 ppm, Cr from 0.05 to 1.60 ppm, Cu from 1.8 to 39.7 ppm and Zn from 8.8 to 117.6 ppm. Although Cr content was relatively homogeneous, Pb, Cd, Cu and Zn distribution in the various mill products proved to be rather inhomogeneous. Maximum contamination for Pb, Cd and Cr, was appreciably lower than in previous studies.

HPLC determination of the total content of aflatoxins in naturally contaminated eggs in free and conjugate forms

A study was undertaken to evaluate the total aflatoxin content in naturally contaminated eggs. Two pools of eggs from laying hens were collected after 2 and 7 days of treatment with aflatoxin B1 (AFB1). An HPLC method has been developed for the determination of AFB1, aflatoxin M1 (AFM1), aflatoxin B2a (AFB2a) and aflatoxicol (Ro) both in free form and after release from water-soluble conjugates. The bound form was cleaned up after acid hydrolysis of the aqueous phase. Eggs collected after 2 days of treatment revealed residues of AFB1, AFB2a and Ro in the organic phase, but none in the aqueous portion. After 7 days of treatment both AFB1 and its hydroxy derivative were found in the organic phase but the aqueous portion showed only hydroxylated metabolites accounting for 35% of the total aflatoxin content.