Increased aflatoxin contamination of dried figs in a drought year

Dried figs (4917 samples) destined for export from Turkey to the European Union were collected between September and December during the very dry crop year of 2007 and tested for aflatoxins B₁, B₂, G₁ and G₂ by immunoaffinity column clean-up and reverse-phase high-performance liquid chromatography (RP-HPLC). While 32% of the samples contained detectable levels of total aflatoxins, 9.8% of them exceeded the European Union limits. Aflatoxin levels were in the range of 0.2–259.46 µg kg^?1 and 2.04–259.46 µg kg^?1 for all samples and samples that exceeded the limits, respectively. A substantial increase in the incidence of aflatoxins was observed in 2007 compared with previous years, most likely due to the drought stress, high temperatures and low relative humidity encountered during the period from January to September of that year. In 2007, the mean temperature was 1–2°C higher, there was 300 mm less total rain, and the mean relative humidity was 10–15% lower than in 2002–06. The average concentration of individual aflatoxins present in the samples was quantified to determine whether the drought conditions promoted certain types of aflatoxins. Among the contaminated samples, aflatoxin B₁ occurred in 97% of the contaminated samples, followed by G₁ in 47%, B₂ in 24%, and G₂ in 6% of samples. Concentrations of individual aflatoxins exhibited great variability among the samples but were not significantly different from those reported in previous studies, which were conducted under conditions without drought and high temperatures.     

Distribution of aflatoxins in shelling and milling fractions of naturally contaminated rice

The objective of this study was to determine the distribution of an economically important class of mycotoxins, the aflatoxins, in rice milling fractions. Rice plants grown under field production conditions are frequently infected with types of pathogenic fungi that produce toxic metabolites (mycotoxins). Paddy (seeds) rice from healthy plants in the field was collected and stored on a farm under humid, poorly ventilated conditions. Samples were milled into four fractions (hulls, brown rice, bran and white rice) and analysed for aflatoxins (B₁, B₂, G₁ and G₂) using a validated method. Rice fractions from healthy plants, which contained low levels of aflatoxins (less than 1?µg?kg^?1), were used to determine the efficiency of the extraction method. Seeds stored under poor conditions were found to be contaminated with aflatoxins B₁ and B₂ as were the fractions. The sums of AFB₁ and AFB₂ in stored paddy rice, hulls, brown rice, bran and white rice were 141, 39, 158, 367 and 56?µg?kg^?1, respectively. The ratio of aflatoxin B₁ and B₂ was about 10?:?1. AFG₁ and AFG₂ were less than 1?µg?kg^?1. Thus, brown rice contained 92.9% of the aflatoxins in paddy rice, whereas white rice contained only 27.9%.     

Aflatoxins and heavy metals in animal feed in Iran

The occurrence of aflatoxin (aflatoxin B₁, aflatoxin B₂, aflatoxin G₁ (AFG₁) and aflatoxin G₂ (AFG₂)) and heavy metal (Pb, Cd, As and Hg) contamination was determined in 40 industrially produced animal feed samples which were collected from the southwest of Iran. The results indicated that 75% of samples were contaminated by four aflatoxins and the level of AFB₁ and sum of aflatoxins were higher than the permissible maximum levels in Iran (5 and 20 µg kg^?1, respectively) in all feed samples. A positive correlation was found between four types of aflatoxins in all the tested samples (p < 0.01) and the positive correlation between AFG₁ and AFG₂ was significant (r² = 0.708). All feed samples had lead concentrations lower than the maximum EU limit, while 5%, 17% and 42.5% of feed samples had As, Cd and Hg concentrations higher than the maximum limits, respectively.     

Occurrence of fumonisins and aflatoxins in cereals from markets of Hebei province of China

Fumonisins B₁, B₂ and B₃ (FB₁, FB₂ and FB₃) and aflatoxins B₁ (AFB₁), B₂ (AFB₂), G₁ (AFG₁) and G₂ (AFG₂) are both major mycotoxins of food concern, because of their wide range of concentration and possible co-occurrence. Therefore, a contamination survey in corn and wheat flour by liquid chromatography–tandem mass spectrometry was carried out. Quantification of fumonisins and aflatoxins was based on internal calibration (by the use of ¹³C₃₄-fumonisin) and external calibration, respectively. Fumonisins were detected in 95% of corn samples and in 7% of wheat flour samples, with the mean level (FB₁?+?FB₂?+?FB₃) of 441?µg?kg^?1 and 0.09?µg?kg^?1, respectively. Low levels of aflatoxins were detected in 37% of the samples with a mean level (B₁?+?B₂?+?G₁?+?G₂) of 0.12?µg?kg^?1. Fumonisins and aflatoxins were not detected in 29% of the samples analysed. Simultaneous occurrence of fumonisins and aflatoxins was observed in 12% of samples.     

Moulds and mycotoxins in rice from the Swedish retail market

A survey of moulds and mycotoxins was performed on 99 rice samples taken from the Swedish retail market. The main objective was to study the mould and mycotoxin content in basmati rice and rice with a high content of fibre. Samples of jasmine rice as well as long-grain rice were also included. The samples were analysed for their content of ochratoxin A (high-performance liquid chromatography (HPLC)), aflatoxin B₁, B₂, G₁, and G₂ (HPLC, RIDA®QUICK), and mould (traditional cultivation methods in combination with morphological analysis). The majority of samples were sampled according to European Commission Regulation 401/2006. Subsamples were pooled and mixed before milling and both mould and mycotoxin analyses were performed on milled rice. The results showed that the majority of basmati rice (71%) and many jasmine rice samples (20%) contained detectable levels of aflatoxin B₁ (level of quantification = 0.1 µg aflatoxin kg^?1 rice). Two samples of jasmine rice and ten basmati rice samples contained levels over the regulated European maximum limits of 2 µg kg^?1 for aflatoxin B₁ or 4 µg kg^?1 for total aflatoxins. Aspergillus was the most common mould genus isolated, but also Penicillium, Eurotium, Wallemia, Cladosporium, Epicoccum, Alternaria, and Trichotecium were found. The presence of Aspergillus flavus in 21% of the samples indicates that incorrect management of rice during production and storage implies a risk of mould growth and subsequent production of aflatoxin. Rough estimates showed that high rice consumers may have an intake of 2–3 ng aflatoxin kg^?1 bodyweight and day^?1 from rice alone. This survey shows that aflatoxin is a common contaminant in rice imported to Europe.     

Aflatoxins in composite spices collected from local markets of Karachi,Pakistan

This survey was carried out to evaluate the occurrence of total aflatoxins (AFs; B₁+B₂+G₁+G₂) in unpacked composite spices. A total of 75 samples of composite spices such as biryani, karhai, tikka, nihari and korma masalas were collected from local markets of Karachi, Pakistan, and analysed using HPLC technique. The results indicated that AFs were detected in 77% (n = 58) samples ranging from 0.68 to 25.74 µg kg^?1 with a mean of 4.63 ± 0.95 µg kg^?1. In 88% (n = 66) samples, AFs level was below the maximum limits (ML = 10 µg kg^?1) as imposed by EU. Furthermore, 61% (n = 46) tested samples contained AFs level between 1 and 10 µg kg^?1, 9% (n = 7) exhibited AFs contamination ranged 10?20 µg kg^?1 and only 3% (n = 2) of the investigated samples contained AFs levels higher than the ML of 20 µg kg^?1 for total aflatoxins as set by the USA. It was concluded that there is need to establish a strict and continuous national monitoring plan to improve safety and quality of spices in Pakistan.     

Validation of a confirmatory analytical method for the determination of aflatoxins B1, B2, G1 and G2 in foods and feed materials by HPLC with on-line photochemical derivatization and fluorescence detection

A sensitive and selective analytical method for the simultaneous separation and quantitative determination of aflatoxins B₁, B₂, G₁ and G₂ in foodstuffs and materials for feed has been validated. The method is based on high performance liquid chromatography with on-line post-column photochemical derivatization and fluorescence detection. The chromatographic separation of aflatoxins was accomplished using a C₁₈ column eluted with an isocratic mobile phase consisting of water, methanol and acetonitrile. The sample preparation required a simple extraction of aflatoxins with MeOH/H₂O (80:20, v/v) and a purification step by immunoaffinity column cleanup. The total analysis time, including sample preparation and chromatographic separation, did not exceed 40 min with a run time of 10 min. The on-line photochemical derivatization ensures better results in terms of simplicity, sensitivity and reproducibility with respect to chemical derivatization techniques, and provides an increase of the peak resolution and an extent of automation in comparison with the electrochemical ones. The procedure for the determination of aflatoxins in food samples and cereals for animal consumption was extensively validated following Regulation (EC) No. 882/2004. Detection limits in wheat bran samples of 0.08 µg kg^?1 for AFB₁, 0.02 µg kg^?1 for AFB₂, 0.16 µg kg^?1 for AFG₁ and 0.04 µg kg^?1 for AFG₂ were attained. The method allows high recovery with mean values ranging from 72 to 94% and it satisfies the necessary requirements for sensitivity, linearity, selectivity, precision and ruggedness, demonstrating the conformity of the method with provisions of Regulation (EC) No. 401/2006.     

Survey of aflatoxins in maize tortillas from Mexico City

In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure. In a survey of 396 2-kg samples, taken over four sampling days in 2006 and 2007 from tortilla shops and supermarkets in Mexico City, aflatoxin levels were quantified by HPLC. In Mexico, the regulatory limit is 12?µg?kg^?1 total aflatoxins for maize tortillas. In this survey, 17% of tortillas contained aflatoxins at levels of 3–385?µg?kg^?1 or values below the limit of quantification (<LOQ) and, of these, 13% were >12?µg?kg^?1 and 87% were below the regulatory limit. Average aflatoxin concentrations in 56 contaminated samples were: AFB₁ (12.1?µg?kg^?1); AFB₂ (2.7?µg?kg^?1); AFG₁ (64.1?µg?kg^?1) and AFG₂ (3.7?µg?kg^?1), and total AF (20.3?µg?kg^?1).     

Aflatoxins and cyclopiazonic acid in feed and milk from dairy farms in São Paulo,Brazil

The occurrence of aflatoxins (AF) B₁, B₂, G₁, G₂ and cyclopiazonic acid (CPA) in feeds, and AFM₁ and CPA in milk was determined in dairy farms located in the northeastern region of São Paulo state, Brazil, between October 2005 and February 2006. AF and CPA determinations were performed by HPLC. AFB₁ was found in 42% of feed at levels of 1.0–26.4 µg kg^?1 (mean: 7.1 ± 7.2 µg kg^?1). The concentrations of AFM₁ in raw milk varied between 0.010 and 0.645 µg l^?1 (mean: 0.104 ± 0.138 µg l^?1). Only one sample was above the tolerance limit adopted in Brazil (0.50 µg l^?1) for AFM₁ in milk. Regarding CPA in feed, six (12%) samples showed concentrations of 12.5–153.3 µg kg^?1 (mean: 57.6 ± 48.7 µg kg^?1). CPA was detected in only three milk samples (6%) at levels of 6.4, 8.8 and 9.1 µg l^?1. Concentrations of aflatoxins and CPA in feed and milk were relatively low, although the high frequency of both mycotoxins indicates the necessity to continuously monitor dairy farms to prevent contamination of feed ingredients.     

Transfer of aflatoxin B1 and fumonisin B1 from naturally contaminated raw materials to beer during an industrial brewing process

The aim of this research was to determine the fate of aflatoxins (AFs) and fumonisins (FBs) naturally occurring in raw materials (maize grit and malted barley) during four industrial brewing processes. The aflatoxin B₁ (AFB₁) level in raw materials varied from 0.31 to 14.85 µg kg^?1, while the fumonisin B₁ (FB₁) level (only in maize grit) varied from 1146 to 3194 µg kg^?1. The concentration in finished beer ranged from 0.0015 to 0.022 µg l^?1 for AFB₁ and from 37 to 89 µg l^?1 for FB₁; the other aflatoxins and fumonisin B₂ were not found in beer samples. The average percentage of toxins recovered in finished beer, referring to the amounts contained in raw materials, were 1.5% ± 0.8% for AFB₁ and 50.7% ± 4.7% for FB₁. These results were mainly due to the different solubility of the two mycotoxins during the mashing process. If raw materials comply with the limits fixed by European Commission Regulations, the contribution of a moderate daily consumption of beer to AFB₁ and FB₁ intake does not contribute significantly to the exposure of the consumer.     

The production of aflatoxins in fresh date fruits and under simulated storage conditions

Sixteen varieties of date fruit (Phoenix dactylifera) at three stages of maturation (Kimri, Rutab and Tamr) were examined for the presence of fungi and analysed for aflatoxins B₁, B₂, G₁ and G₂ and sterigmatocystin. Single samples of each variety were used in the study. Samples as received were initially examined for mycoflora and toxin levels and then stored at 98% relative humidity and 30 °C for 14 days to investigate the effects of possible adverse storage conditions on mycoflora and, in particular, aflatoxin formation. All samples showed an absence of aflatoxins and their precusor, sterigmatocystin, after adverse storage for 14 days, although aflatoxin‐producing Aspergillus flavus isolates were identified in 10 varieties at the first stage of maturation (Kimri). High fungal counts were associated with the Rutab stage and low counts with the Tamr stage. The counts of A flavus ranged from 5.00 to 8.16 log₁₀(cfu g^?1) under simulated storage conditions, and three varieties contained significant levels of aflatoxin B₁ or B₂ ranging from 35 to 11 610 µg kg^?1. Sterigmatocystin was not detected in any of the samples as received or under simulated storage conditions. © 2002 Society of Chemical Industry     

LC–MS/MS multi-method for mycotoxins after single extraction,with validation data for peanut,pistachio, wheat,maize, cornflakes,raisins and figs

Mycotoxin analysis is usually carried out by high performance liquid chromatography after immunoaffinity column cleanup or in enzyme-linked immunosorbent assay tests. These methods normally involve determination of single compounds only. EU legislation already exists for the aflatoxins, ochratoxin A and patulin in food, and legislation will come into force for deoxynivalenol, zearalenone and the fumonisins in 2007. To enforce the various legal limits, it would be preferable to determine all mycotoxins by routine analysis in different types of matrices in one single extract. This would also be advantageous for HACCP control purposes. For this reason, a multi-method was developed with which 33 mycotoxins in various products could be analysed simultaneously. The mycotoxins were extracted with an acetonitrile/water mixture, diluted with water and then directly injected into a LC–MS/MS system. The mycotoxins were separated by reversed-phase HPLC and detected using an electrospray ionisation interface (ESI) and tandem MS, using MRM in the positive ion mode, to increase specificity for quality control. The following mycotoxins could be analysed in a single 30-min run: Aflatoxins B₁, B₂, G₁ and G₂, ochratoxin A, deoxynivalenol, zearalenone, T-2 toxin, HT-2 toxin, α-zearalenol, α-zearalanol, β-zearalanol, sterigmatocystin, cyclopiazonic acid, penicillic acid, fumonisins B₁, B₂ and B₃, diacetoxyscirpenol, 3- and 15-acetyl-deoxynivalenol, zearalanone, ergotamin, ergocornin, ergocristin, α-ergocryptin, citrinin, roquefortin C, fusarenone X, nivalenol, mycophenolic acid, alternariol and alternariol monomethyl ether. The limit of quantification for the aflatoxins and ochratoxin A was 1.0 µg kg^?1 and for deoxynivalenol 50 µg kg^?1. The quantification limits for the other mycotoxins were in the range 10–200 µg kg^?1. The matrix effect and validation data are presented for between 13 and 24 mycotoxins in peanuts, pistachios, wheat, maize, cornflakes, raisins and figs. The method has been compared with the official EU method for the determination of aflatoxins in food and relevant FAPAS rounds. The multi-mycotoxin method has been proven by the detection of more than one mycotoxin in maize, buckwheat, figs and nuts. The LC–MS/MS technique has also been applied to baby food, which is subject to lower limits for aflatoxin B₁ and ochratoxin A, ergot alkaloids in naturally contaminated rye and freeze-dried silage samples.     

Surveys of aflatoxin B1 contamination of retail Turkish foods and of products intended for export between 2007 and 2009

Surveys were carried out between 2007 and 2009 to determine the aflatoxin B₁ content of 3345 commercial Turkish foodstuffs supplied by producers for testing for their own purposes or for export certification. To simplify the reporting of data, foods were categorized as: 1, high sugar products with nuts; 2, nuts and seeds; 3, spices; 4, grain; 5, cocoa products; 6, dried fruit and vegetables; 7, processed cereal products; 8, tea; and 9, baby food and infant formula. Aflatoxin analysis was carried out by high-performance liquid chromatography with fluorescence detection after immunoaffinity column clean-up, with a recoveries ranging from 91% to 99%, depending on the matrix. Of the 3345 samples analysed, 94% contained aflatoxin B₁ below the European Union limit of 2 µg kg^?1, which applies to nuts, dried fruit, and cereals products. The 6% of the 206 contaminated samples were mainly nuts and spices. For pistachios, 24%, 38%, and 42% of the totals of 207, 182, and 24 samples tested for 2007, 2008 and 2009, respectively, were above 2 µg kg^?1, with 50 samples containing aflatoxin B₁ at levels ranging from 10 to 477 µg kg^?1.     

Aflatoxin accumulation in whole crop maize silage as a result of aerobic exposure

BACKGROUND: Most of the maize silage stored in horizontal silos is exposed to air and can be spoiled by fungi. Potentially toxigenic fungi have been found in maize silage, and about 300 mycotoxins have been detected. Among these mycotoxins, the most harmful for feed and food safety are aflatoxins. The aim of the study was to set up a specific method to detect aflatoxins in maize silage, and to investigate whether aflatoxin contamination in maize silage depends on the level of field contamination of the crop, and whether the occurrence of aerobic spoilage during ensiling has any effect on the final contamination of the silage. RESULTS: A method for the determination of aflatoxin B₁, B₂, G₁ and G₂ in maize silage using high‐performance liquid chromagraphy with fluorescence detection has been developed and validated. Recoveries of aflatoxin B₁, B₂, G₁, and G₂ spiked over the 0.25 to 5 µg kg^?1 range averaged 74–94%. The results of laboratory scale and farm scale ensiling experiments indicated that aflatoxins could increase when silage is exposed to air during conservation or during the feed‐out phase. CONCLUSIONS: The method here proposed to detect aflatoxins in silages has proved to be sensitive and is able to detect levels of 0.1 and 0.5 ng mL^?1 for AFB₁ and AFG₁, and between 0.025 and 0.125 ng mL^?1 for AFB₂ and AFG₂. This study also provides evidence of aflatoxin accumulation in whole crop maize silage as a result of aerobic exposure. Copyright © 2011 Society of Chemical Industry     

Aflatoxin occurrence in milk and supplied concentrates of goat farms of north‐eastern Italy

BACKGROUND: There is little information about the occurrence of aflatoxin M₁ in goat milk. A survey involving 17 dairy goat farms of north‐eastern Italy was completed during 2005 and 2006, in order to evaluate the prevalence of milk contamination and its relationship with type and level of concentrate supplied. RESULTS: 132 concentrate and 85 milk samples were collected during five farm visits and analysed for aflatoxins. Aflatoxin B₁ (AFB₁) was > 0.1 µg kg^?1 in two‐thirds of the feeds and > 5 µg kg^?1 in nine. Contamination was higher in maize than in other pure feeds (median: 0.8 versus 0.1 µg kg^?1); complementary feeds showed intermediate values. Aflatoxin M₁ (AFM₁) was > 3 ng kg^?1 in one‐third of milks and > 25 ng kg^?1 in three. All the milk samples were below EU statutory limits. The farm ranks for milk AFM₁ level and the peak of concentrate AFB₁ contamination were significantly correlated (0.642). CONCLUSIONS: Risk to human health was generally found to be absent, with only a few cases involving feed contamination to be monitored. The main aflatoxin risk for goat milk could arise from maize and maize‐based concentrates in the more intensive breeding conditions. Copyright © 2008 Society of Chemical Industry     

Intake of aflatoxins through the consumption of peanut products in Brazil

To estimate daily intake of aflatoxins from peanut products consumed by the population of Paraná State (Brazil), 100 samples of peanut products were collected between July 2006 and April 2007. Aflatoxins were determined by an HPLC method with fluorescence detection. There was a 50% occurrence of aflatoxins (B₁, B₂, G₁ and G₂) in concentrations ranging from 0.5 to 113?ng?g^?1, with 13 samples with levels above 20?ng?g^?1. Intake was calculated for average and high adult consumers of peanut products and it was compared with provisional maximum tolerable daily intake (PMTDI). The estimated probable daily intake (PDI) for aflatoxin B₁ (AFB₁) varied from 0.6 to 10.4?ng?kg^?1?bw?day^?1, exceeding the PMTDI of 0.4?ng?kg^?1?bw?day^?1 for carriers of hepatitis B virus.     

Determination of aflatoxins in edible oil from markets in Hebei Province of China by liquid chromatography–tandem mass spectrometry

Analysis of aflatoxin B₁ (AFB₁), B₂ (AFB₂), G₁ (AFG₁) and G₂ (AFG₂) in 76 edible oil samples (peanut oil, soybean oil, corn embryo oil and blended oil) was performed by liquid chromatography–tandem mass spectrometry (LC–MS/MS). The oils were sampled from three areas (Shijiazhuang, Baoding and Tangshan) of Hebei Province of China. AFB₁ was detected in 22 samples representing 28.9%, followed by AFB₂ (7.89%) and AFG₁ (3.95%), while no AFG₂ contamination was detected in any samples. AFB₁ levels in oil samples ranged 0.14–2.72?µg?kg^?1 and AFB₂ ranged 0.15–0.36?µg?kg^?1, while lower levels of 0.01–0.02?µg?kg^?1 for AFG₁ were recorded. The paper is part of an on-going investigation of aflatoxin contamination in Chinese edible oils.     

SCREENING AND QUANTIFICATION OF AFLATOXINS AND OCHRATOXIN A IN DIFFERENT CEREALS CULTIVATED IN ROMANIA USING THIN-LAYER CHROMATOGRAPHY-DENSITOMETRY

ABSTRACT

The main focus of our study was to implement a rapid, inexpensive and reliable method that could be utilized to check the cereals for safety (i.e., screening for total aflatoxins, as well as individual B₁, B₂, G₁, G₂ aflatoxins and ochratoxin A). We developed a protocol by which we were able to isolate mycotoxins from cereals collected from different regions of Romania. After extraction in chloroform, the mycotoxins were separated by thin‐layer chromatography (TLC) and quantified using densitometry. Forty‐three samples of different cereals (wheat, maize, rye and Triticale) were analyzed. Twenty‐five of the 43 samples (58.14% of the total number) were found to be contaminated with different mycotoxins in various concentrations: aflatoxin B₁ (1.6–5.7 µg/kg), aflatoxin B₂ (0.89–4 µg/kg), aflatoxin G₁ (1.2–5.76 µg/kg), aflatoxin G₂ (0.96–3.4 µg/kg) and/or 4.3–30 µg/kg ochratoxin A. The concentration of total aflatoxin contamination ranged from 11.2 to 10.8 µg/kg. Among the different cereals, the highest number of contaminated samples was found to be in the wheat samples (62.5%). The method outlined in this study has been adopted already by our laboratory for current analyses of mycotoxins. The results obtained using this method is in compliance with the strict regulatory guidelines developed both in Romania, as well as in the European Union.

PRACTICAL APPLICATIONS

Thin‐layer chromatography (TLC) is a rapid, inexpensive and convenient method that can be used routinely to screen for mycotoxins. This article describes the detailed procedures for the extraction, purification and quantification of aflatoxins and ochratoxin A, using TLC. Using this method one can identify concomitantly five different mycotoxins and by coupling it with densitometry a quantitative determination is also possible. Therefore, this could become a routine technique in regional laboratories responsible for checking agrifood safety.     

Aflatoxin levels in raw and processed hazelnuts in Turkey

Aflatoxin levels in hazelnut samples obtained from exporter companies were monitored over a 3-year period. A total of 3188 samples of raw and processed hazelnuts were analysed using an HPLC method. The total aflatoxin content of the contaminated samples was in the range of 0.02–78.98?µg?kg^?1 for hazelnut kernels, 0.07–43.59?µg?kg^?1 for roasted hazelnut kernels, 0.02–39.17?µg?kg^?1 for roasted sliced hazelnut kernels, and 0.02–11.20?µg?kg^?1 for hazelnut purees, respectively, showing that the variations of aflatoxin contamination were very high. The results of aflatoxin analysis revealed that the aflatoxin contamination in the hazelnut samples was at a tolerable level. A total of 3147 samples were contaminated with aflatoxins, although below the legal limits. However, the aflatoxin contents of 41 samples exceeded the legal limits. Therefore, aflatoxin contents of hazelnuts should be monitored regularly to minimise the risk of aflatoxin hazard, and pre- and post-harvest strategies should be developed to prevent aflatoxin formation.     

Co-occurrence of fumonisins with aflatoxins in home-stored maize for human consumption in rural villages of Tanzania

This study determined maize-user practices that influence the presence of fumonisin and aflatoxin contamination of maize in food consumed in the rural areas of Tanzania. Samples of the 2005 maize harvest in Tanzania were collected from 120 households and examined for fumonisins and aflatoxins. Information on whether the maize was sorted to remove defective (visibly damaged or mouldy) maize before storage and whether the damaged and mouldy maize or the non-dehulled maize was used as food was also collected. In addition, the percentage of defective kernels in the samples was determined. Ninety per cent of the households sorted out defective maize, 45% consumed the defective maize and 30% consumed non-dehulled maize. In 52% of the samples fumonisins were determined at levels up to 11,048 µg kg^?1 (median = 363 µg kg^?1) and in 15% exceeded 1000 µg kg^?1; the maximum tolerable limit (MTL) for fumonisins in maize for human consumption in other countries. Aflatoxins were detected in 18% of the samples at levels up to 158 µg kg^?1 (median = 24 µg kg^?1). Twelve per cent of the samples exceeded the Tanzanian limit for total aflatoxins (10 µg kg^?1). Aflatoxins co-occurred with fumonisins in 10% of the samples. The percentage defective kernels (mean = 22%) correlated positively (r = 0.39) with the fumonisin levels. Tanzanians are at a risk of exposure to fumonisins and aflatoxins in maize. There is a need for further research on fumonisin and aflatoxin exposure in Tanzania to develop appropriate control strategies.