German Cano-Sancho

Mycotoxins: occurrence, toxicology, and exposure assessment.

Mycotoxins are abiotic hazards produced by certain fungi that can grow on a variety of crops. Consequently, their prevalence in plant raw materials may be relatively high. The concentration of mycotoxins in finished products is usually lower than in raw materials. In this review, occurrence and toxicology of the main mycotoxins are summarised. Furthermore, methodological approaches for exposure assessment are described. Existing exposure assessments, both through contamination and consumption data and biomarkers of exposure, for the main mycotoxins are also discussed.

Occurrence of aflatoxin M1 and exposure assessment in Catalonia (Spain).

BACKGROUND Aflatoxin M₁ (AFM₁) is the main monohydroxylated derivative of aflatoxin B₁ (AFB₁) formed in liver and excreted into milk. Although AFM₁ is less toxic than AFB₁, it has been classified as a possible human carcinogen, Group 2B agent by International Agency for Research on Cancer (IARC). OBJECTIVES The objectives of this study were (i) to determine the occurrence of AFM₁ in the main dairy products consumed in Catalonia region (Spain), and (ii) to assess the exposure of Catalonian population to aflatoxin M₁ through deterministic and probabilistic method. METHODS Occurrence of Aflatoxin M₁ (AFM₁) was determined in 72 composites of milk, 72 composites of cheese and 72 composites of yoghurt from Catalonia. AFM₁ content was analysed using an Enzyme-Linked ImmunoSorbent Assay commercial kit. Three approaches to exposure assessment were conducted: one deterministic method and two probabilistic models with Monte Carlo simulations. RESULTS AFM₁ was detected in 94.4% (68/72) of whole UHT milk samples, in 2.8% (2/72) of yoghurt samples and not detected in cheese. The maximum level was detected in one yoghurt sample with 51.58 ng/kg, only this sample being over the legal EU limit of 50 ng/kg. Milk, cheese and yoghurt mean concentrations were 9.29±2.61, <12.5 and 13.22±4.82 ng/kg, respectively. CONCLUSIONS According to these values, it should be expected Catalonian population is not exposed to a significant risk from aflatoxin M₁ including average and high consumers.

Determination of aflatoxins, deoxynivalenol, ochratoxin A and zearalenone in wheat and oat based bran supplements sold in the Spanish market.

The aflatoxins (AFs), deoxynivalenol (DON), ochratoxin A (OTA) and zearalenone (ZEA) are mycotoxins produced by fungal species which can contaminate, alone or simultaneously, cereal-based raw materials. Usually, the higher mycotoxins concentrations in cereals are found in the external layers of the grain (bran). Nowadays bran is increasingly consumed for its high fibre concentration. The objectives of this study were determining the concentration of these mycotoxins in bran samples intended for direct human consumption and to study the influence of some characteristics of the samples that may affect the mycotoxins content, there are not studies about fibre for direct human consumption. 67 bran samples from shops and supermarkets from two different Spanish cities were analyzed, being 37 samples of wheat bran and the remaining of oat bran. The results showed a major presence of DON in the analyzed samples, with levels above the EU legislation in some samples. Presence of DON was more frequent in wheat samples, compared to oats ones (p<0.05). Extruded or toasted samples, subjected to a heat treatment during processing, presented a significantly lower concentration of OTA, and differences between the organically and conventionally produced samples were also detected in OTA, which showed higher levels in the organic samples. Co-occurrence was frequently found between the Fusarium mycotoxins (ZEA and DON). Due to the high levels of DON in the analyzed samples, a calculation of DON intake has been made and it has been demonstrated that bran can account for an important percentage of DON exposure in the total diet.

Quantitative dietary exposure assessment of the Catalonian population (Spain) to the mycotoxin deoxynivalenol

The mycotoxin deoxynivalenol (DON) is one of the most common contaminants of cereals worldwide, and its occurrence has been widely reported in raw foods and foodstuffs, around the European region, including Catalonia. In the present work, a stochastic methodology has been applied to accurately assess the exposure of the Catalonian population (Spain) to DON through food consumption. Raw contamination data was provided by a large survey conducted in this region, in addition to the raw consumption data from a nutritional study specifically designed to assess the dietary intake of the main foodstuffs related to DON contamination for all population age groups. Contamination and consumption data were combined by simulation using an essentially parametric (P-P) method. The P-P method draws sampling values from distribution functions fitted to consumption and contamination data sets. Moreover, to quantify the accuracy and reliability of the statistics estimates, we built the related confidence intervals using a pseudo-parametric bootstrap method. Considering the results drawn from the P-P simulation method, the Catalonian population should be expected to be exposed at moderated levels of deoxynivalenol, the infants and individuals with ethnic dietary patterns being the most exposed population groups

Exposure assessment to ochratoxin A in Catalonia (Spain) based on the consumption of cereals, nuts, coffee, wine, and beer

Ochratoxin A (OTA) was analysed in composite samples of cereal-based baby foods, beer, breakfast cereals (corn- and rice and wheat-based), loaf bread, peanuts and pistachios. Foodstuffs were collected in hypermarkets and supermarkets from 12 cities in the Spanish region of Catalonia, and composite samples were prepared for analysis involving liquid–liquid extraction, followed by immunoaffinity column clean-up and HPLC with fluorescence detection. Consumption data for the selected foodstuffs were collected by means of a food-frequency questionnaire. The studied population was grouped by age in infants, children, adolescents and adults; and exposure to OTA through the specified foodstuffs, and through wine and coffee, was assessed. Exposure assessment was done through deterministic and probabilistic modelling of the contamination and consumption data. OTA occurrence and mean of positive samples (ng g−1 or ng ml−1, for beer) were the following: 8.7% and 0.233 in baby foods; 88.7% and 0.022 in beer; 2.8% and 0.728 in corn-based breakfast cereals; 25% and 0.293 in wheat-based breakfast cereals; 12.9% and 0.283 in loaf bread; 41.7% and 0.241 in peanuts; and 2.9% and 0.228 in pistachios. The median estimated daily intake of OTA through the foodstuffs by each age group were below the latest provisional tolerable daily intakes (PTDIs) of 17 and 14 ng kg−1 bw day−1 recommended by the European Food Safety Authority (EFSA) in 2006 and the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 2007, respectively, ranging from 1% and 2% of those values in adolescents and children, to 3% and 11% in adults and infants.

Ochratoxin A and its metabolite ochratoxin alpha in urine and assessment of the exposure of inhabitants of Lleida, Spain

Ochratoxin A (OTA) as well as its metabolite ochratoxin α (OTα) were detected in human urine in order to assess the exposure to OTA of a group of 72 adult inhabitants of the city of Lleida (Spain). Urine samples were enzymatically treated; OTA and OTα were separated by liquid-liquid extraction, and detected by HPLC-fluorescence. Exposure to OTA was also evaluated by the estimation of its daily intake from food contamination data from the literature and from food consumption data provided by the participants, who filled in a food frequency questionnaire (FFQ) and a three-day food consumption record (3DR). OTA occurrence (12.5%, limit of detection=0.034 ng/mL) was lower than OTα occurrence (61.1%, limit of detection=0.023 ng/mL). The range of concentrations was 0.057-0.562 ng/mL and 0.056-2.894 ng/mL for OTA and for OTα, respectively. It could be observed for positive samples that the FFQ data were related to the OTA concentration in urine, whereas the 3DR data were related to the OTα levels in urine. The OTA estimated daily intake of the participants was lower than 30% of the latest provisional tolerable daily intake of 14 ng/kg body weight/day in the worst cases of exposure.

Occurrence and exposure assessment of aflatoxins in Catalonia (Spain).

The main objective of this study was to assess the exposure of Catalonian (Spain) population to AFs. Thus, two sub-objectives were considered: (1) to assess the occurrence of AFs in food marketed in Catalonia, and (2) to assess the consumption of those foods susceptible to AFs contamination by Catalonian population. AFs were analysed in a total of 603 samples considering special commodities as free-gluten, ethnic or baby foods. Analytical method consisted of an extraction and clean-up of aflatoxins step using immunoaffinity columns, and determination by HPLC with post-column photochemical derivatization and fluorescence detection. Food dietary intake was assessed using a food frequency questionnaire, administered to 1387 individuals by trained interviewers. Contamination and consumption raw datasets were combined by means of a direct method and a stochastic method, building the pseudo-parametric bootstrap confidence intervals of the main outputs. Margins of exposure (MoE) and cancer incidence were estimated for the different collectives. The highest percentages of positive samples were found in red pepper, pistachios and peanuts. Considering our results, the most exposed group was the celiac sufferer collective followed by the adolescents; however health concern should not be expected in the population groups.

Occurrence of fumonisins in Catalonia (Spain) and an exposure assessment of specific population groups

Fumonisin B1 (FB1) and B2 (FB2) are mycotoxins produced by Fusarium verticillioides and F. proliferatum and common contaminants of cereal crops. The objectives of this study were to (1) study the occurrence of fumonisins in Catalonia (north-eastern region of Spain) and (2) assess the exposure of the Catalonian population to these mycotoxins. Contamination data was provided by a wide survey where 928 individual samples were pooled to analyse 370 composite samples. Fumonisins were extracted and purified using immunoaffinity columns and determined by HPLC with fluorescence detection. The raw consumption data came from a nutritional study specifically designed to assess the dietary intake of the main foodstuffs related to fumonisin contamination for all population age groups. In addition, two specific groups were selected with respect to maize consumption: immigrants and celiac sufferers. Contamination and consumption data were combined by simulation using an essentially parametric–parametric (P-P) method. The P-P method draws sampling values from distribution functions fitted to consumption and contamination datasets. Moreover, to quantify the accuracy and reliability of the statistical estimates, we built related confidence intervals using a Pseudo-Parametric bootstrap method. The results of this study show that fumonisins are commonly found in some commodities on the Catalonian market, such as beer, corn snacks and ethnic foods; however, the values were well below the permitted maximum EU levels. The most exposed group were infants followed by immigrants but, in all cases, they were below the TDI of 2 µg/kg bw/day.

Occurrence of zearalenone, an oestrogenic mycotoxin, in Catalonia (Spain) and exposure assessment

The objectives of this study were to assess the occurrence of zearalenone (ZEA) in food in Catalonia (Spain); to assess the consumption of the main food items contaminated with ZEA; and finally, to estimate the dietary exposure of the Catalonian population to the mycotoxin. Therefore 1187 samples were collected from the Catalonian market and pooled to obtain 485 analytical samples (composites) of the commodities most susceptible to ZEA contamination and commonly consumed in the region. Extraction and clean-up was performed using immunoaffinity columns and ZEA was detected and quantified by high performance liquid chromatography (HPLC) and fluorescence detection. A specific food frequency questionnaire (FFQ) was administered to 1264 individuals by trained interviewers to estimate the consumption of the relevant foods. The results showed that the occurrence of ZEA in food marketed in Catalonia was infrequent. Sliced bread, corn snacks and sweet corn were the commodities where it was most often present. In considering the contamination levels and food consumption estimates, the dietary intake of ZEA by the Catalonian population was estimated to be considerably lower than the temporary tolerable daily intake (TDI) of 200 ng ZEA kg(-1) bw day(-1).

Effect of food processing on exposure assessment studies with mycotoxins.

The goals of the present work were, on the one hand, to assess the effect of baking on the stability of zearalenone (ZEA) and deoxynivalenol (DON), as well as the transfer of DON from pasta to boiling water, and, on the other hand, to quantify the impact of DON depletion, during cooking of pasta, on overall exposure estimates. Therefore, the bread-making process was simulated on a pilot-plant scale by using naturally contaminated flour with DON and ZEA. Transfer of DON from pasta to water was evaluated at different boiling times. Pasta was prepared on a pilot-plant scale by using naturally contaminated durum wheat flour; subsequently, it was boiled simulating home cooking. The experiments examined the stability of DON and ZEA during the bread-making process, including fermentation with Saccharomyces cerevisiae and baking at 200°C. Our results showed a high transfer of DON from pasta to boiling water, reaching depletion levels of almost 75%, which correlated with levels found in water. Accordingly, these cooking depletion rates were computed through a stochastic exposure model to weight their impact on the final exposure estimates. Finally, statistically significant differences were found in most of the parameters and populations assessed, but these were not enough to consider the process as protective because the contribution of pasta to the overall DON intake was commonly low.