Community movement and COVID-19: a global study using Google's Community Mobility Reports

Google's 'Community Mobility Reports' (CMR) detail changes in activity and mobility occurring in response to COVID-19. They thus offer the unique opportunity to examine the relationship between mobility and disease incidence. The objective was to examine whether an association between COVID-19-confirmed case numbers and levels of mobility was apparent, and if so then to examine whether such data enhance disease modelling and prediction. CMR data for countries worldwide were cross-correlated with corresponding COVID-19-confirmed case numbers. Models were fitted to explain case numbers of each country's epidemic. Models using numerical date, contemporaneous and distributed lag CMR data were contrasted using Bayesian Information Criteria. Noticeable were negative correlations between CMR data and case incidence for prominent industrialised countries of Western Europe and the North Americas. Continent-wide examination found a negative correlation for all continents with the exception of South America. When modelling, CMR-expanded models proved superior to the model without CMR. The predictions made with the distributed lag model significantly outperformed all other models. The observed relationship between CMR data and case incidence, and its ability to enhance model quality and prediction suggests data related to community mobility could prove of use in future COVID-19 modelling.

Fungal diversity and metabolomic profiles in GM and isogenic non-GM maize cultivars from Brazil

There is little knowledge of the microbial diversity, mycotoxins and associated secondary metabolites in GM maize and isogenic non-GM cultivars (cvs). This study has quantified the microbial populations and dominant fungal genera in 6 cvs of each type representative of herbicide, pesticide or stacked resistance to both. The predominant mycotoxins and targeted metabolomics profiles were also compared between the two sets of cvs. This showed that the overall fungal populations were 8.8 CFUs g⁻¹ maize. The dominant genera, isolated from maize samples, whether surface-sterilised or not, in all maize cvs were Fusarium, followed by Penicillium, Aspergillus and occasionally Cladosporium and Alternaria. The analysis of the targeted metabolomics showed that approx. 29 different metabolites were detected. These were dominated by fumonisins and minor Penicillium spp. metabolites (questiomycin A and rugulovasine A). Interestingly, the range and number of mycotoxins present in the GM cvs were significantly lower than in the non-GM maize samples. This suggests that while the fungal diversity of the two types of maize appeared to be very similar, the major contaminant mycotoxins and range of toxic secondary metabolites were much lower in the GM cvs.

Effect of interacting conditions of water activity, temperature and incubation time on Fusarium thapsinum and Fusarium andiyazi growth and toxin production on sorghum grains

This study examined the effect of interacting conditions of water activity (a_W, 0.995, 0.98 and 0.95) and temperature (15, 25 and 30 °C) on growth rate of two Fusarium thapsinum and one F. andiyazi strains isolated from sorghum in Argentina. In addition, the effect of interacting conditions (a_W × temperature × incubation time (7, 14, 21 and 28 days)) on mycotoxin production (moniliformin (MON), fusaric acid (FA) and fusarin C (FUS C)) on a sorghum grain substrate was evaluated. Statistical analysis showed that a_W and temperature significantly affected growth of both species, mainly the a_W. Incubation time significantly influenced mycotoxin production by both species as well, mostly for FA. Maximum growth rates of the F. thapsinum strains were obtained at the highest a_W (0.995) and 25 °C and growth rate decreased as a_W and temperature were reduced. The same growth profile was observed for F. andiyazi RCFA09 (maximum growth rates at 0.995-25 °C). Mycotoxin production by both species was detected at the highest a_W levels whereas at 0.95 a_W only low amounts of MON were produced by F. thapsinum. Maximum MON and FUS C production by both F. thapsinum strains was observed at 0.995 a_W and 25-30 °C after 28 days of incubation. Also, F. thapsinum strains showed maximum FA production at the highest a_W and temperature but after 14 days; after this incubation time toxin levels significantly decreased. The responses to a_W and temperature of F. andiyazi were similar to that of F. thapsinum strains in relation to FA and FUS C production. Maximum levels of FA were detected at the highest a_W after 14 days of incubation at 25-30 °C. Fusarin C was produced at all assayed temperatures but maximum levels were detected at 30 °C and 0.995 a_W after 28 days of incubation. Two-dimensional profiles on the interactions of a_W by temperature were developed from these data to identify conditions that indicate a significant risk from MON, FA and FUS C accumulation on sorghum grains. The results of this study suggest that sorghum grains could be colonized by these species and toxin production can occur, especially during development stages under field conditions at high water activity of grains or during grain storage if the drying process is slow or deficient. To our knowledge, this study described for the first time FUS C production by F. thapsinum and F. andiyazi under interacting conditions of a_W, temperature and incubation time on sorghum grains.

Carbon dioxide production as an indicator of Aspergillus flavus colonisation and aflatoxins/cyclopiazonic acid contamination in shelled peanuts stored under different interacting abiotic factors

Aspergillus flavus is the main xerophylic species colonising stored peanuts resulting in contamination with aflatoxins (AFs) and cyclopiazonic acid (CPA). This study evaluated the relationship between storage of shelled peanuts under interacting abiotic conditions on (a) temporal respiration (R) and cumulative CO₂ production, (b) dry matter losses (DMLs) and (c) aflatoxin B₁ (AFB₁) and CPA accumulation. Both naturally contaminated peanuts and those inoculated with A. flavus were stored for 7-days under different water activities (a_w; 0.77-0.95) and temperatures (20-35°C). There was an increase in the temporal CO₂ production rates in wetter and warmer conditions, with the highest respiration at 0.95 a_w + A. flavus inoculum at 30°C (2474 mg CO₂kg^-1h^-1). The DMLs were modelled to produce contour maps of the environmental conditions resulting in maximum/minimum losses. Maximum mycotoxin contamination was always at 0.95 a_w although optimal temperatures were 25-30°C for AFs and 30-35°C for CPA. These results showed a correlation between CO₂ production and mycotoxin accumulation. They also provide valuable information for the creation of a database focused on the development of a post-harvest decision support system to determine the relative risks of contamination with these mycotoxins in stored shelled peanuts.

Influence of storage environment on maize grain: CO2 production, dry matter losses and aflatoxins contamination

Poor storage of cereals, such as maize can lead to both nutritional losses and mycotoxin contamination. The aim of this study was to examine the respiration of maize either naturally contaminated or inoculated with Aspergillus flavus to examine whether this might be an early and sensitive indicator of aflatoxin (AF) contamination and relative storability risk. We thus examined the relationship between different interacting storage environmental conditions (0.80-0.99 water activity (a_w) and 15-35°C) in naturally contaminated and irradiated maize grain + A. flavus on relative respiration rates (R), dry matter losses (DMLs) and aflatoxin B1 and B2 (AFB1-B2) contamination. Temporal respiration and total CO₂ production were analysed by GC-TCD, and results used to calculate the DMLs due to colonisation. AFs contamination was quantified at the end of the storage period by HPLC MS/MS. The highest respiration rates occurred at 0.95 a_w and 30-35°C representing between 0.5% and 18% DMLs. Optimum AFs contamination was at the same a_w at 30°C. Highest AFs contamination occurred in maize colonised only by A. flavus. A significant positive correlation between % DMLs and AFB1 contamination was obtained (r = 0.866, p < 0.001) in the irradiated maize treatments inoculated with A. flavus. In naturally contaminated maize + A. flavus inoculum loss of only 0.56% DML resulted in AFB1 contamination levels exceeding the EU legislative limits for food. This suggests that there is a very low threshold tolerance during storage of maize to minimise AFB1 contamination. This data can be used to develop models that can be effectively used in enhancing management for storage of maize to minimise risks of mycotoxin contamination.

Diversity and fate of fungal metabolites during the preparation of oshikundu, a Namibian traditional fermented beverage

Sorghum and pearl millet, ingredients for the popular Namibian traditional fermented beverage oshikundu, are prone to fungal infection, raising concerns for consumer health from mycotoxin exposure. This study aimed at determining the diversity of fungal metabolites in street-vended ingredients and their transfer rates into oshikundu. A total of 105 samples (40 sorghum malt, 40 pearl millet, 25 oshikundu) were analysed for 700 fungal, bacterial and plant metabolites, using liquid chromatography-tandem mass spectrometry. Of 98 quantified metabolites, 84 were fungal, some being mycotoxins. Aspergillus metabolites were most prevalent (50%, n=42), including aflatoxins, aflatoxin precursors, cyclopiazonic acid and 3-nitropropionic acid from Aspergillus flavus; helvolic acid, gliotoxin and fumiquinazolines from Aspergillus fumigatus and cytochalasin E, patulin and tryptoquivalines from Aspergillus clavatus. High levels of up to 2,280 μg/kg for cyclopiazonic acid and 11,900 μg/kg for 3-nitropropionic acid were quantified in sorghum malts. Other metabolites included fumonisins, curvularin, alternariol and dihydroergosine produced by Fusarium, Penicillium, Alternaria and Claviceps genera, respectively. European Union legislated mycotoxins occurred in cereals at a prevalence range of 3-75%, while none were quantifiable in oshikundu. Aflatoxin B1 was quantified in pearl millet meals (13%) and sorghum malts (50%), with 15% sorghum malts having levels above the European Union regulatory limit of 5 μg/kg. Fumonisin B1 was quantified in pearl millet meals (50%) and sorghum malts (75%) at maximum levels of 3,060 μg/kg and 123 μg/kg respectively, and levels in 5% pearl millet meals were above the European Union regulatory limit of 2,000 μg/kg. Zearalenone and ochratoxin A were quantified in the cereals at levels below European Union regulatory limits. For most metabolites quantifiable in oshikundu, transfer rates from cereals to oshikundu were above 50%, necessitating the use of good quality ingredients for preparing oshikundu and assessment of consumer exposure to mycotoxins.

Mycotoxin contamination of foods in Southern Africa: A 10-year review (2007-2016)

Major staple foods in Southern Africa are prone to mycotoxin contamination, posing health risks to consumers and consequent economic losses. Regional climatic zones favor the growth of one or more main mycotoxin producing fungi, Aspergillus, Fusarium and Penicillium. Aflatoxin contamination is mainly reported in maize, peanuts and their products, fumonisin contamination in maize and maize products and patulin in apple juice. Lack of awareness of occurrence and risks of mycotoxins, poor agricultural practices and undiversified diets predispose populations to dietary mycotoxin exposure. Due to a scarcity of reports in Southern Africa, reviews on mycotoxin contamination of foods in Africa have mainly focused on Central, Eastern and Western Africa. However, over the last decade, a substantial number of reports of dietary mycotoxins in South Africa have been documented, with fewer reports documented in Botswana, Lesotho, Malawi, Mozambique, Zambia and Zimbabwe. Despite the reported high dietary levels of mycotoxins, legislation for their control is absent in most countries in the region. This review presents an up-to-date documentation of the epidemiology of mycotoxins in agricultural food commodities and discusses the implications on public health, current and recommended mitigation strategies, legislation, and challenges of mycotoxin research in Southern Africa.

Experimental mould growth and mycotoxin diffusion in different food items

Isolates of Penicillium commune, Penicillium crustosum, Penicillium expansum, Penicillium roqueforti and Aspergillus versicolor, were inoculated on different food items (hard cheese, crème fraiche, tomato purée, apple and blueberry jam) and incubated at 15 °C for 14 days at 50% relative humidity (RH). After incubation the food samples were divided into 3 subsamples; A was 0-2 cm from the surface and including the fungal colony, subsample B was 2-4 cm and subsample C was the rest from >4 cm from the surface. The subsamples were analysed with a multianalyte method capable of identifying more than several hundreds of fungal metabolites. The outcome showed that mouldy food can contain a cocktail of bioactive secondary metabolites including mycotoxins and sometimes at high concentrations. Measurements of the diffusion of fungal metabolites from the colony on the surface (layer A) into the food (layer B and C) showed that the fungal metabolites do not diffuse more than 2 cm into the inner core of the hard cheese. On the other hand in more liquid foods, such as crème fraiche, fruit jams and tomato purée, the toxins diffused quite readily throughout the entire food sample. The levels of patulin found in the apple jam indicate that the tolerable daily intake for patulin may easily be exceeded even if the mouldy layer A is removed. This limited study calls for more similar studies to be performed to give risk managers a sound basis for advice to consumers.

Masked mycotoxins: does breeding for enhanced Fusarium head blight resistance result in more deoxynivalenol-3-glucoside in new wheat varieties?

From economic and environmental points of view, enhancing resistance to Fusarium head blight (FHB) in wheat is regarded as the best option to reduce fungal colonisation and the concomitant mycotoxin contamination. This review focuses on the effect of FHB resistance on deoxynivalenol (DON) and the masked metabolite deoxynivalenol-3-glucoside (DON-3-glucoside) in wheat. Based on published information complemented with our own results we draw the following conclusions: (1) All investigated wheat cultivars can convert DON to DON-3-glucoside. Hence, detoxification of DON to DON-3-glucoside is not a new trait introduced by recent resistance breeding against FHB. (2) The amount of DON-3-glucoside relative to DON contamination can be substantial (up to 35%) and is among other things dependent on genetic and environmental factors. (3) Correlation analyses showed a highly significant relationship between the amount of FHB symptoms and DON contamination: breeding for FHB resistance reduces DON contamination. (4) DON contamination data are highly correlated with DON-3-glucoside concentration data: in other words, reduction of DON content through resistance breeding results in a concomitant reduction in DON-3-glucoside content. (5) The DON-3-glucoside/DON ratio increases with decreasing DON contamination: the most resistant lines with the lowest DON contamination show the highest relative level of DON-3-glucoside to DON. In summary, introgressing FHB resistance reduces both DON and DON-3-glucoside levels in the grain, but the reduction is lower for the masked toxin. DON-3-glucoside can represent a possible hazard to human and animal health, especially in wheat samples contaminated with DON close to permitted limits.

Safe food and feed through an integrated toolbox for mycotoxin management: the MyToolBox approach

There is a pressing need to mobilise the wealth of knowledge from the international mycotoxin research conductedover the past 25-30 years, and to perform cutting-edge research where knowledge gaps still exist. This knowledgeneeds to be integrated into affordable and practical tools for farmers and food processors along the chain inorder to reduce the risk of mycotoxin contamination of crops, feed and food. This is the mission of MyToolBox – a four-year project which has received funding from the European Commission. It mobilises a multi-actorpartnership (academia, farmers, technology small and medium sized enterprises, food industry and policystakeholders) to develop novel interventions aimed at achieving a significant reduction in crop losses due tomycotoxin contamination. Besides a field-to-fork approach, MyToolBox also considers safe use options ofcontaminated batches, such as the efficient production of biofuels. Compared to previous efforts of mycotoxin reduction strategies, the distinguishing feature of MyToolBox is to provide the recommended measures to theend users along the food and feed chain in a web-based MyToolBox platform (e-toolbox). The project focuseson small grain cereals, maize, peanuts and dried figs, applicable to agricultural conditions in the EU and China. Crop losses using existing practices are being compared with crop losses after novel pre-harvest interventionsincluding investigation of genetic resistance to fungal infection, cultural control (e.g. minimum tillage or cropdebris treatment), the use of novel biopesticides suitable for organic farming, competitive biocontrol treatment and development of novel modelling approaches to predict mycotoxin contamination. Research into post-harvestmeasures includes real-time monitoring during storage, innovative sorting of crops using vision-technology, novelmilling technology and studying the effects of baking on mycotoxins at an industrial scale.

Microbial secondary metabolites in homes in association with moisture damage and asthma

We aimed to characterize the presence of microbial secondary metabolites in homes and their association with moisture damage, mold, and asthma development. Living room floor dust was analyzed by LC-MS/MS for 333 secondary metabolites from 93 homes of 1-year-old children. Moisture damage was present in 15 living rooms. At 6 years, 8 children had active and 15 lifetime doctor-diagnosed asthma. The median number of different metabolites per house was 17 (range 8-29) and median sum load 65 (4-865) ng/m(2) . Overall 42 different metabolites were detected. The number of metabolites present tended to be higher in homes with mold odor or moisture damage. The higher sum loads and number of metabolites with loads over 10 ng/m(2) were associated with lower prevalence of active asthma at 6 years (aOR 0.06 (95% CI <0.001-0.96) and 0.05 (<0.001-0.56), respectively). None of the individual metabolites, which presence tended (P < 0.2) to be increased by moisture damage or mold, were associated with increased risk of asthma. Microbial secondary metabolites are ubiquitously present in home floor dust. Moisture damage and mold tend to increase their numbers and amount. There was no evidence indicating that the secondary metabolites determined would explain the association between moisture damage, mold, and the development of asthma.

Fungal secondary metabolite analysis applied to Cultural Heritage: the case of a contaminated library in Venice

The secondary metabolite production of several fungal strains of Aspergillus creber, Aspergillus jensenii, Aspergillus penicillioides, Aspergillus protuberus, Aspergillus vitricola, Cladosporium cladosporioides, Eurotium chevalieri, Eurotium halophilicum, Penicillium brevicompactum and Penicillium chrysogenum were characterised by liquid chromatography tamdem mass spectometry. All fungi were isolated from both air and book covers as well as from settled dust from a contaminated library in Venice (Italy). For A. creber and A. jensenii, we identified sterigmatocystin, methoxysterigmatocystin, versicolorin A and related precursors/side metabolites from the biosynthetic pathways. Deoxybrevianamid E, neoechinulin A, pseurotin A and D, and rugulusovin were principally detected from the strains of E. halophilicum, an emerging fungal species implicated in book contaminations in specific indoor niches. The analysis of settled dust showed a wide range of toxic or bioactive fungal metabolites. Forty-five different metabolites were identified in different concentrations; in particular, high amounts of asperglaucide, alamethicin, andrastin A, terrecyclic acid and neoechinulin A were detected. Also one bacterial metabolite, chloramphenicole was detected. This study increases the knowledge about metabolite production of several fungal species, as well as on the indoor presence of fungi that are not detected by aerobiological sampling. These results emphasise how routine dusting operations are necessary and essential in order to prevent further microbiological developments in library environments.

Mycotoxin profile of Fusarium armeniacum isolated from natural grasses intended for cattle feed

Fusarium armeniacum has been found as a saprophyte on natural grasses devoted to cattle feed in Argentina. This species has been reported as highly toxigenic due to the production of trichothecenes type A, but the information available about its toxigenic profile is incomplete. Thus, the aim of the present study was to determine the toxigenic ability of 50 F. armeniacum isolates recovered from natural grasses using a multitoxin method based on LC-MS/MS. In addition, morphological identification of 15 selected isolates was confirmed by sequencing the translation elongation factor 1α. Out of the 327 metabolites analysed, only 10 were detected: T-2 toxin (T-2), T-2 triol, T-2 tetraol, HT-2 toxin (HT-2), diacetoxyscirpenol (DAS), monoacetoxyscirpenol (MAS), neosolaniol (NEO), aurofusarin (AUF), beauvericin (BEA) and zearalenone (ZEA). The most common group of mycotoxins produced by the isolates on rice under laboratory conditions was trichothecenes type A, and some minor Fusarium mycotoxins, such as BEA and AUF. Some isolates were also able to produce ZEA. Among the trichothecene type A, HT-2, T-2, NEO were clearly synthesised at the highest levels and frequency, followed by DAS and MAS. HT-2, T-2, NEO and DAS production was detected in 48 (96%), 47 (94%), 47 (94%) and 38 (76%) isolates, respectively. The ability of F. armeniacum, to produce ZEA and AUF has been demonstrated here for the first time. Given the new information provided about the toxigenic profile of this species, commonly associated with natural grasses in Argentina, the threat to animal health posed by this fungus should not be underestimated.

Effect of fungicide application to control Fusarium head blight and 20 Fusarium and Alternaria mycotoxins in winter wheat (Triticum aestivum L.)

Azole fungicides have been reported to be the most effective active substances in the control of Fusarium Head Blight (FHB) and in the reduction of the main mycotoxins that occur in cereal grain, such as deoxynivalenol (DON). Four field experiments have been conducted in North West Italy, over a period of 2 growing seasons, in order to evaluate the effect of azole fungicide (prothioconazole) applications on the prevalence of emerging mycotoxins in common winter wheat under naturally-infected field conditions. Wheat samples have been analysed by means of a dilute-and-shoot multi-mycotoxin LC-MS/MS method. Twenty fungal metabolites were detected: enniatins, aurofusarin, moniliformin, equisetin, DON, deoxynivalenol-3-glucoside, culmorin, bikaverin, beauvericin, fumonisins, fusaric acid, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, zearalenone, decalonectrin, butenolide, tentoxin, alternariol and alternariol methyl ether. The most abundant fungal metabolites were DON and culmorin, with an average contamination in the untreated control of 1,360 μg/kg and 875 μg/kg, respectively, in the growing season with the highest disease pressure (2011-2012). On average, the results have shown that the fungicide application significantly reduced the enniatins (from 127 μg/kg to 46 μg/kg), aurofusarin (from 62 μg/kg to 21 μg/kg), moniliformin (from 32 μg/kg to 16 μg/kg), tentoxin (from 5.2 μg/kg to 2.5 μg/kg) and equisetin (from 0.72 μg/kg to 0.06 μg/kg) contents in all the experiments. However, DON, deoxynivalenol-3-glucoside and culmorin were only significantly reduced in the growing season with the highest disease pressure. The other fungal metabolites were mainly found in traces in the untreated plots. These results, which have been obtained in different environmental and agronomic conditions, have underlined for the first time that the fungicide usually applied to control the FHB and DON content, also consistently reduces the main emerging mycotoxins of winter wheat in temperate areas.

Fungal metabolites diversity in maize and associated human dietary exposures relate to micro-climatic patterns in Malawi

This study investigated the diversity of fungal metabolites in maize across four agro-ecological zones of Malawi. A total of 90 maize samples (for human consumption), collected from farmsteads, were analysed for 235 fungal metabolites using liquid chromatography-tandem mass spectrometry. A total of 65 metabolites were found in the samples. 75% of samples from the hottest agro-ecological zone contained either aflatoxins, fumonisins, deoxynivalenol, zearalenone; or a combination thereof in levels exceeding European Union (EU) maximum levels, whereas the related fraction was only 17% in the cool temperature zone. Aflatoxins, citrinin, 3-nitropropionic acid, monocerin and equisetin were most prevalent and in higher levels in samples from hot agro-ecological zones, whereas deoxynivalenol, nivalenol, zearalenone and aurofusarin were most prevalent in cool agro-ecologies. On the basis of per-capita maize consumption, estimated daily intakes for all samples from hot ecologies were well above the JECFA's provisional maximum tolerable daily intake (PMTDI) of 2.0 μg/kg body weight (bw)/day for fumonisins, whereas the PMTDI of 1.0 μg/kg bw/day for deoxynivalenol was exceeded in relatively more (90%) samples from the cool highlands than the other zones. These results demonstrate the influence of micro-climatic conditions on mycotoxin prevalence patterns and underscores the need for development of agro-ecological specific mycotoxin dietary exposure management strategies.

Mycotoxins and other fungal metabolites in grain dust from Norwegian grain elevators and compound feed mills

Employees at grain elevators and compound feed mills are exposed to large amounts of grain dust during work, frequently leading to airway symptoms and asthma. Although the exposure to grain dust, microorganisms, β-1→3-glucans and endotoxins has been extensively studied, the focus on the mycotoxin content of grain dust has previously been limited to one or few mycotoxins. Our objective was therefore to screen settled grain dust from grain elevators and compound feed mills for fungal metabolites by LC/MS-MS and explore differences between work places, seasons and climatic zones. Seventy fungal metabolites and two bacterial metabolites were detected. Trichothecenes, depsipeptides, ergot alkaloids, and other metabolites from Fusarium, Claviceps, Alternaria, Penicillium, Aspergillus, and other fungi were represented. The prevalence of individual metabolites was highly variable, and the concentration of each metabolite varied considerably between samples. The prevalence and concentration of most metabolites were higher in grain elevators compared to compound feed mills. Differences between seasons and climatic zones were inconclusive. All samples contained multiple mycotoxins, indicating a highly complex pattern of possible inhalational exposure. A mean exposure of 20 ng/m3 of fungal metabolites was estimated, whereas a worst case scenario estimated as much as 10 ?g/m3. Although many of these compounds may be linked to toxicological and immunological effects through experimental or epidemiological studies, it still remains to be determined whether the detected concentrations implicate adverse health outcomes when inhaled.

Quantitation of multiple mycotoxins and cyanogenic glucosides in cassava samples from Tanzania and Rwanda by an LC-MS/MS-based multi-toxin method

A multi-mycotoxin method based on liquid chromatography/tandem mass spectrometry (LC-MS/MS) was used for a mycotoxin survey in 627 samples of processed cassava collected from different districts across Tanzania and Rwanda after the method performance for this matrix had been determined. Matrix effects as well as extraction efficiencies were found to be similar to most other previously investigated matrices with the exception of distinct matrix effects in the negative ionisation mode for early eluting compounds. Limits of detection were far below the regulatory limits set in the European Union for other types of commodities. Relative standard deviations were generally lower than 10% as determined by replicates spiked on two concentration levels. The sample-to-sample variation of the apparent recoveries was determined for 15 individually spiked samples during three different analytical sequences. The related standard deviation was found to be lower than 15% for most of the investigated compounds, thus confirming the applicability of the method for quantitative analysis. The occurrence of regulated mycotoxins was lower than 10% (with the exception of zearalenone) and the related limits were exceeded only in few samples, which suggests that cassava is a comparatively safe commodity as regards mycotoxins. The most prevalent fungal metabolites were emodin, kojic acid, beauvericin, tryptophol, 3-nitropropionic acid, equisetin, alternariol methylether, monocerin, brevianamide F, tenuazonic acid, zearalenone, chrysophanol, monilifomin, enniatins, apicidin and macrosporin. The related concentrations exceeded 1 mg kg(-1) only in few cases. However, extremely high levels of cyanogenic plant toxins, which had been previously added to the method, were observed in few samples, pointing out the need for improved post-harvest management to decrease the levels of these compounds.

Evaluation of zearalenone, α-zearalenol, β-zearalenol, zearalenone 4-sulfate and β-zearalenol 4-glucoside levels during the ensiling process

Zearalenone-producing Fusarium species can contaminate maize before ensiling and cause reproductive problems in animals. Suspect feeds are only routinely analysed for zearalenone (ZEA), not considering other oestrogenic metabolites or masked derivatives. The aims of the present study were to monitor the levels of ZEA, α-zearalenol (α-ZOL), β-zearalenol (β-ZOL), zearalenone-4-sulfate (ZEA-4S) and β-zearalenol-4-glucoside (β-ZOL-4G) in artificially contaminated maize silage and determine the effect of the ensiling process on these toxins. A laboratory silo model was designed using polystyrene bags filled with previously contaminated chopped whole-plant maize, stored in a dry and cool room and sampled at days 7, 45, 90, 120 and 127. ZEA, α-ZOL, β-ZOL, ZEA-4S and β-ZOL-4G levels were quantified by liquid chromatography – tandem mass spectrometry. Chemical and physical analysis indicated silage maintained good quality in all stages. pH was reduced favourably (P<0.05) from 4.69 to 3.80 during the preservation stage. Dry matter, moisture content and water activity did not vary from day 7 to 127. ZEA, α-ZOL, β-ZOL and ZEA-4S levels also did not change from day 7 to 127, indicating no significant degradation by the ensiling process or silage-native microbiota. This study suggests that ZEA levels remain invariable during the ensiling process, as well as the levels of its derivatives. The presence of highly oestrogenic metabolites, like α-ZOL and the masked ZEA-4S, which are not screened in the routine analyses, increases the overall toxicity of ZEA-contaminated silage.

Comparison of single and multi-analyte methods based on LC-MS/MS for mycotoxin biomarker determination in human urine

The performances of four LC-MS/MS methodologies for determination of up to eight mycotoxin biomarkers in human urines were compared by involving three laboratories that analysed common urine samples spiked at two levels of each biomarker. Each laboratory received a calibration solution, spiked urines and the corresponding unspiked urine. The two spiking levels for each biomarker were chosen by considering the levels naturally occurring in human urines and the limits of quantification of the LC-MS/MS methodologies used by the participating laboratories. The results of each laboratory were evaluated for their z-score values. The percentage of satisfactory z-scores (| z | < 2) were: 100% for deoxynivalenol, de-epoxy deoxynivalenol, aflatoxin M1, β-zearalenol and zearalenone, 87% for α-zearalenol, 50% for ochratoxin A and 42% for fumonisin B1. Good method performances were obtained for most biomarkers at the levels tested in this study, as demonstrated by the overall percentage of satisfactory z-scores for all analytes (87%). Unsatisfactory/questionable z-scores (| z | ≯2) were obtained for fumonisin B1 (7/12 results), ochratoxin A (4/8 results) and ?-zearalenol (1/8 results). The percentage of satisfactory z-scores for fumonisin B1 and ochratoxin A increased from 42 to 83% for fumonisin B1 and from 50 to 62% for ochratoxin A when laboratories 1 and 2 used own calibrants. Factors that could explain the different results obtained for fumonisin B1 and ochratoxin A with provided and own calibration solutions could not be identified in this study and should be carefully investigated in future studies.

Mycotoxins in corn and wheat silage in Israel

Silage is an important feed source for intensive dairy herds worldwide. Fungal growth and mycotoxin production before and during silage storage is a well-known phenomenon, resulting in reduced nutritional value and a possible risk factor for animal health. With this in mind, a survey was conducted to determine for the first time the occurrence of mycotoxins in corn and wheat silage in Israel. A total of 30 corn and wheat silage samples were collected from many sources and analysed using a multi-mycotoxin method based on LC-MS/MS. Most mycotoxins recorded in the present study have not been reported before in Israel. Overall, 23 mycotoxins were found in corn silage; while wheat silage showed a similar pattern of mycotoxin occurrence comprising 20 mycotoxins. The most common post-harvest mycotoxins produced by the Penicillium roqueforti complex were not found in any tested samples, indicative of high-quality preparation and use of silage. Moreover, none of the European Union-regulated mycotoxins--aflatoxin B1, ochratoxin, T-2 toxin, diacetoxyscirpenol and deoxynivalenol--were found above their limits of detection (LODs). The Alternaria mycotoxins--macrosporin, tentoxin and alternariol methyl ether--were highly prevalent in both corn and wheat silage (>80%), but at low concentrations. The most prominent (>80%) Fusarium mycotoxins in corn silage were fusaric acid, fumonisins, beauvericin, monilifomin, equisetin, zearalenone and enniatins, whereas in wheat silage only beauvericin, zearalenone and enniatins occurred in more than 80% of the samples. The high prevalence and concentration of fusaric acid (mean = 765 µg kg⁻¹) in Israeli corn silage indicates that this may be the toxin of highest potential concern to dairy cow performance. However, more data from different harvest years and seasons are needed in order to establish a more precise evaluation of the mycotoxin burden in Israeli silage.

Fungal and mycotoxin assessment of dried edible mushroom in Nigeria

In order to determine whether dried mushrooms are a foodstuff that may be less susceptible to infection by toxigenic molds and consequently to mycotoxin contamination, 34 dried market samples were analyzed. Fungal population was determined in the samples by conventional mycological techniques and molecular studies, while the spectrum of microbial metabolites including mycotoxins was analyzed by a liquid chromatography tandem mass spectrometric method covering 320 metabolites. Molds such as Fusarium, Penicillium, Trichoderma and aflatoxigenic species of Aspergillus (Aspergillus flavus and Aspergillus parvisclerotigenus) were recovered from all samples at varying levels. None of the mycotoxins addressed by regulatory limits in the EU was positively identified in the samples. However, 26 other fungal metabolites occurred at sub- to medium μg/kg levels in the samples, including aflatoxin/sterigmatocystin bio-precursors, bis-anthraquinone derivatives from Talaromyces islandicus, emerging toxins (e.g. enniatins) and other Fusarium metabolites, and clavine alkaloids. Although little is known on the toxicology of these substances, the absence of aflatoxins and other primary mycotoxins suggests that dried mushrooms may represent a relatively safe type of food in view of mycotoxin contamination.

Fungal and bacterial metabolites in commercial poultry feed from Nigeria

Metabolites of toxigenic fungi and bacteria occur as natural contaminants (e.g. mycotoxins) in feedstuffs making them unsafe to animals. The multi-toxin profiles in 58 commercial poultry feed samples collected from 19 districts in 17 states of Nigeria were determined by LC/ESI-MS/MS with a single extraction step and no clean-up. Sixty-three (56 fungal and seven bacterial) metabolites were detected with concentrations ranging up to 10,200 µg kg⁻¹ in the case of aurofusarin. Fusarium toxins were the most prevalent group of fungal metabolites, whereas valinomycin occurred in more than 50% of the samples. Twelve non-regulatory fungal and seven bacterial metabolites detected and quantified in this study have never been reported previously in naturally contaminated stored grains or finished feed. Among the regulatory toxins in poultry feed, aflatoxin concentrations in 62% of samples were above 20 µg kg⁻¹, demonstrating high prevalence of unsafe levels of aflatoxins in Nigeria. Deoxynivalenol concentrations exceeded 1000 µg kg⁻¹ in 10.3% of samples. Actions are required to reduce the consequences from regulatory mycotoxins and understand the risks of the single or co-occurrence of non-regulatory metabolites for the benefit of the poultry industry.

Synthesis of deoxynivalenol-3-ß-D-O-glucuronide for its use as biomarker for dietary deoxynivalenol exposure

Trichothecene mycotoxins are prevalent toxic secondary metabolic products of several fungal species and pose a serious threat to human and animal health. Deoxynivalenol (DON) is known to undergo rapid metabolisation after uptake. The formed glucuronides are urinary excreted and could therefore serve as possible biomarkers for daily uptake measurement. So far human exposure to the major toxin DON was estimated from dietary average intake or by measurement of the parent toxin after hydrolysis. These approaches are indirect and time-consuming. Due to the clear demand for a direct determination method and lack of an available reference substance we synthesised DON-3-O-ö-D-glucuronide. The Königs-Knorr procedure using acetobromo-α-D-glucuronic acid methyl ester as glucuronyl-donor was optimised to produce the target compound in mg scale allowing subsequent characterisation via nuclear magnetic resonance and LC-MS/MS.

Occurrence of deoxynivalenol and its 3-beta-D-glucoside in wheat and maize

Deoxynivalenol-3-beta-D-glucoside (D3G), a phase II plant metabolite of the mycotoxin deoxynivalenol (DON), occurs in naturally Fusarium-contaminated cereals. In order to investigate the frequency of occurrence as well as the relative and absolute concentrations of D3G in naturally infected cereals, 23 wheat samples originating from fields in Austria, Germany and Slovakia as well as 54 maize samples from Austrian fields were analysed for DON and D3G by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Both analytes were detected in all the 77 field samples. DON was found at levels from 42 to 4130 ng g(-1) (977 +/- 1000 ng g(-1) on average). The D3G concentrations in all cereal samples were in the range 10-1070 ng g(-1) (216 +/- 253 ng g(-1) on average), corresponding to about 5-46 mol% of their DON concentrations (15 +/- 8 mol% on average).

Single-kernel analysis of fumonisins and other fungal metabolites in maize from South African subsistence farmers

Fumonisins are important Fusarium mycotoxins mainly found in maize and derived products. This study analysed maize from five subsistence farmers in the former Transkei region of South Africa. Farmers had sorted kernels into good and mouldy quality. A total of 400 kernels from 10 batches were analysed; of these 100 were visually characterised as uninfected and 300 as infected. Of the 400 kernels, 15% were contaminated with 1.84-1428 mg kg(-1) fumonisins, and 4% (n=15) had a fumonisin content above 100 mg kg(-1). None of the visually uninfected maize had detectable amounts of fumonisins. The total fumonisin concentration was 0.28-1.1 mg kg(-1) for good-quality batches and 0.03-6.2 mg kg(-1) for mouldy-quality batches. The high fumonisin content in the batches was apparently caused by a small number (4%) of highly contaminated kernels, and removal of these reduced the average fumonisin content by 71%. Of the 400 kernels, 80 were screened for 186 microbial metabolites by liquid chromatography-tandem mass spectrometry, detecting 17 other fungal metabolites, including fusaric acid, equisetin, fusaproliferin, beauvericin, cyclosporins, agroclavine, chanoclavine, rugulosin and emodin. Fusaric acid in samples without fumonisins indicated the possibility of using non-toxinogenic Fusaria as biocontrol agents to reduce fumonisin exposure, as done for Aspergillus flavus. This is the first report of mycotoxin profiling in single naturally infected maize kernels.

Co-occurrence of toxic bacterial and fungal secondary metabolites in moisture-damaged indoor environments

Toxic microbial secondary metabolites have been proposed to be related to adverse health effects observed in moisture-damaged buildings. Initial steps in assessing the actual risk include the characterization of the exposure. In our study, we applied a multi-analyte tandem mass spectrometry-based methodology on sample materials of severely moisture-damaged homes, aiming to qualitatively and quantitatively describe the variety of microbial metabolites occurring in building materials and different dust sample types. From 69 indoor samples, all were positive for at least one of the 186 analytes targeted and as many as 33 different microbial metabolites were found. For the first time, the presence of toxic bacterial metabolites and their co-occurrence with mycotoxins were shown for indoor samples. The bacterial compounds monactin, nonactin, staurosporin and valinomycin were exclusively detected in building materials from moist structures, while chloramphenicol was particularly prevalent in house dusts, including settled airborne dust. These bacterial metabolites are highly bioactive compounds produced by Streptomyces spp., a group of microbes that is considered a moisture damage indicator in indoor environments. We show that toxic bacterial metabolites need to be considered as being part of very complex and diverse microbial exposures in 'moldy' buildings.

PRACTICAL IMPLICATIONS

Bacterial toxins co-occur with mycotoxins in moisture-damaged indoor environments. These compounds are measurable also in settled airborne dust, indicating that inhalation exposure takes place. In attempts to characterize exposures to microbial metabolites not only mycotoxins but also bacterial metabolites have to be targeted by the analytical methods applied. We recommend including analysis of samples of outdoor air in the course of future indoor assessments, in an effort to better understand the outdoor contribution to the indoor presence of microbial toxins. There is a need for a sound risk assessment concerning the exposure to indoor microbial toxins at concentrations detectable in moisture-damaged indoor environments.

A comparative study of qualitative immunochemical screening assays for the combined measurement of T-2/HT-2 in cereals and cereal-based products

Many different immunochemical platforms exist for the screening of naturally occurring contaminants in food from the low cost enzyme linked immunosorbent assays (ELISA) to the expensive instruments such as optical biosensors based on the phenomenon of surface plasmon resonance (SPR). The primary aim of this study was to evaluate and compare a number of these platforms to assess their accuracy and precision when applied to naturally contaminated samples containing HT-2/T-2 mycotoxins. Other important factors considered were the speed of analysis, ease of use (sample preparation techniques and use of the equipment) and ultimately the cost implications. The three screening procedures compared included an SPR biosensor assay, a commercially available ELISA and an enzymelinked immunomagnetic electrochemical array (ELIME array). The qualitative data for all methods demonstrated very good overall agreements with each other, however on comparison with mass spectrometry confirmatory results, the ELISA and SPR assay performed slightly better than the ELIME array, exhibiting an overall agreement of 95.8% compared to 91.7%. Currently, SPR is more costly than the other two platforms and can only be used in the laboratory whereas in theory both the ELISA and ELIME array are portable and can be used in the field, but ultimately this is dependent on the sample preparation techniques employed. Sample preparative techniques varied for all methods evaluated, the ELISA was the most simple to perform followed by that of the SPR method. The ELIME array involved an additional clean-up step thereby increasing both the time and cost of analysis. Therefore in the current format, field use would not be an option for the ELIME array. In relation to speed of analysis, the ELISA outperformed the other methods.

Stability and epimerisation behaviour of ergot alkaloids in various solvents

In this paper the stability and degree of epimerisation of six major ergot alkaloids at three different temperature levels (-20 °C, +4 °C and +20 °C) over periods of 18 hours and six weeks is reported for the first time. The behaviour of ergometrine, ergocornine, ergocristine, α-ergocryptine, ergosine and ergotamine was thoroughly studied in seven solvents which are employed for the preparation of calibrants and extraction mixtures, respectively. Moreover, the stability of the ergot alkaloids was tested in different cereal extracts (rye, wheat, barley, oats) for 1, 2 and 6 days. Of the toxins tested, the ergopeptide-type toxins ergosine, ergotamine, ergocornine, α-ergocryptine and ergocristine showed similar behaviour patterns. The simple lysergic acid derivative ergometrine was more stable and showed hardly any epimerisation to ergometrinine, with the sum of both epimers remaining constant in all seven solvents. The ergopeptides tested show variable epimerisation tendencies, and were also less stable during six weeks at 20 °C. Ergosine showed the highest degree of epimerisation (43% after 6 weeks at 20 °C). In general, the order of epimerisation promotion was methanol/dichloromethane > acetonitrile/buffer > extraction mix > stabilising solution > acetonitrile >> chloroform. Long-term storage at room temperature can only be carried out in chloroform, which showed no epimerisation for all toxins even at 20 °C and also kept the sum of R and S forms constant, which indicates no formation of aci-epimers or other degradation products. Long-term storage of ergot alkaloids in acetonitrile, the most convenient solvent with respect to HPLC analysis, should be carried out at temperatures of -20 °C or below. The constant epimer ratio of all ergot alkaloids in the extraction mixture acetonitrile/ammonium carbonate buffer (200 mg/l; 92:8, v/v) during an HPLC run (18 hours) demonstrates the stability of the toxins in this extraction mixture.

Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) determination of phase II metabolites of the mycotoxin zearalenone in the model plant Arabidopsis thaliana

The biotransformation products of zearalenone, a Fusarium mycotoxin, were elucidated using the model plant Arabidopsis thaliana. After treatment of plant seedlings with 50 microM zearalenone, both the liquid media and the plant extracts were analysed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). An array of 17 different metabolites, most prominently glucosides, malonylglucosides, di-hexose- and hexose-pentose disaccharides of zearalenone, and alpha- and beta-zearalenol, were detected in the samples. Time courses for the different zearalenone metabolites were recorded and they give a closer insight into the metabolism kinetics. A scheme proposing the zearalenone metabolism in A. thaliana is given. The aspect of food safety regarding the (potential) occurrence of masked mycotoxins in agricultural commodities is discussed.

Investigation of the storage stability of selected volatile sulfur compounds in different sampling containers

The suitability of various sample containers (i.e. standard Tedlar sample bags, black/clear layered Tedlar sample bags and Silcosteel sample cylinders) was examined for a gaseous multicomponent standard containing methylmercaptan, ethylmercaptan, dimethyl sulfide, ethylmethyl sulfide, 2-propylmercaptan, 1-propylmercaptan, 2-butylmercaptan, diethyl sulfide and 1-butylmercaptan (1 mg/m3 each in nitrogen). In the black/clear layered Tedlar sample bags, significant losses (up to 10% for methylmercaptan as the most critical component) were observed after 2 days, whereas in the standard Tedlar sample bags the recovery of methylmercaptan was approximately 90% even after 1 week. The Silcosteel sample cylinders were suitable for sampling of volatile sulfur compounds with respect to the stability of the analytes, but the recoveries exceeded 100% especially for the higher boiling compounds, which was attributed to enrichment effects on parts of the sampling system.