Aflatoxins In Nuts Research Articles

Risk assessment of dietary exposure to aflatoxins in nuts and spices. A pilot study in Yerevan, Armenia

The study aimed to assess aflatoxin (AFB1, AFB2, AFG1, AFG2) exposure and potential health risks through nuts and spices consumption by adults (age 18-65, n = 554) in the capital city of Yerevan, where one-third of the Armenian population resides. AFs occurrence in nuts (peanut, almond, pistachio) and spices (black pepper, red pepper, mix of spices) was detected using HPLC. Daily consumption of products among the adult population was collected using a method of Food Frequency Questionnaire. The deterministic approach for risk assessment involved calculating the estimated daily intake and margin of exposure (MOE) of AFs, based on the EFSA benchmark dose of 0.4 μg/kg bw/day. AFs contents in products ranged from 0.011 μg/kg (mixed spices) to 0.391 μg/kg (ground red pepper), all below the EU regulatory limits. Ground black pepper was the main contributor to estimated exposure and a health concern (i.e. MOE<10000) was identified for high consumers in the worst-case scenario. Moreover, a health concern was present for individuals with a consumption of all studied food items (41% of the sample). Comparison with studies from neighboring countries and global data emphasizes the need for continuous monitoring and regulation to mitigate aflatoxin exposure risks in countries of the Caucasus area and globally.

Fungal Isolation, Detection, and Quantification of Aflatoxins in Nuts Sold in the Lebanese Market

This study examines the prevalence of aflatoxin contamination in 160 nut samples, both shelled and unshelled (including pistachios, peanuts, and walnuts), from the Lebanese market, focusing on their fungal contamination and specific toxigenic strains. Aflatoxin B1 (AFB1), known for its potent carcinogenic and immunosuppressive properties, was detected in various samples. Moisture content analysis showed that unshelled nuts often exceeded maximum moisture limits more frequently than shelled nuts, with levels ranging from 1.9 to 9.5%. The predominant fungal genus identified through cultivation on potato dextrose agar (PDA) plates was Aspergillus. In total, 55% of samples were contaminated with A. flavus and 45% with A. niger. All toxigenic strains isolated were identified as Aspergillus flavus. The aflatoxins, particularly AFB1, were quantified using the enzyme-linked immunosorbent assay (ELISA) and reversed-phase high-performance liquid chromatography (HPLC), revealing contamination in 43.8% of the samples, with concentrations ranging from 0.4 to 25 µg/kg. Some samples notably exceeded the established maximum tolerable limits (MTLs) for AFB1, set between 2 and 8 µg/kg. Shelled pistachios showed the highest contamination rate at 52% and were the most frequent to surpass the MTL of 8 µg/kg for pistachios, whereas walnuts displayed the lowest contamination levels, with only 15.4% exceeding the MTL for aflatoxins.

Aflatoxins in the nut chains: strategies to reduce their impact on consumer’s health and economic losses

Abstract The presence of Aspergillus section Flavi and aflatoxins (AFs) in nut chains are of great concern due to the toxic effects of AFs on human and animal health as well as the economic losses during commercialisation. Extreme events related to climate change like increased temperature, severe rainfalls and droughts are modulating factors of fungal growth and mycotoxin production. The Expert Working Group (EWG) on nuts that worked under the frame of the Horizon 2020 Mycokey Project prepared this review based on discussions about the situation of contamination with AFs in nuts and the available strategies to reduce the impact of these toxins in the nut chains. The EWG selected as examples peanuts, pistachios and Brazil nuts, and discussed in the review the importance of nut value chains in the production, commercialisation and regulations that establish maximum levels for AFs. Also data on the Rapid Alert System for Food and Feed (RASFF) was considered and showed several notifications for mycotoxins, mainly AFs for nuts and nut products, such as pistachio nuts and dried mix nuts. Under a scenario of climate change, we elaborated strategies to prevent AFs contamination with emphasis on biocontrol and decision support systems. Also, the relevance of strategies to prevent and reduce both fungal infection and AFs accumulation in peanuts, Brazil nuts and pistachio are included as guidelines.

Comprehensive and sensitive validation of the method and determination of measurement uncertainty for simultaneous specification of aflatoxin B1, B2, G1 and G2 in nuts

In this study, a comprehensive and sensitive validation study of the legally used method was conducted to simultaneously determine the levels of aflatoxin B1, B2, G1, and G2 in nuts. The applied method has been extensively evaluated in terms of in-laboratory detection limit and quantification limit, linearity, selectivity, precision, recovery, accuracy, adequacy, and measurement uncertainty. Levels of aflatoxins were examined by a validated immunoaffinity column-high performance liquid chromatography-post column derivatization-fluorescence detection (IAC-HPLC-PCA-FLD) analytical method. Detection limits (LOD) for aflatoxin G2, G1, B2, and B1 were found to be 0.05 μg/kg, 0.13 μg/kg, 0.06 μg/kg, and 0.15 μg/kg, respectively. The regression coefficient (R2) was greater than 0.999 according to constructed calibration curves for all aflatoxin components. Thus, the curves exhibited satisfactory linearity within the analyzed range. The combined standard uncertainty values for precision (RSD%) studies were below 10%. It showed a robust and reliable sensitivity with <10% RSD with the test procedure. Average recovery values were detected as 67-84% for hazelnut and 60-89% pistachio. All aflatoxin components in hazelnut paste, which is the proficiency test material, were determined within an appropriate |Z|-score range (≤ 2). The relative expanded uncertainty of measurement was 0.80 μg/kg for AFB1 and AFG1, 0.83 μg/kg for AFB2 and AFG2, and 0.78 μg/kg for total AFs. The results showed that the approved method for the investigation and monitoring of aflatoxins in hazelnuts and pistachios is highly sensitive, robust, reliable, selective, and reproducible. Validation parameters can be successfully used in routine analysis to monitor aflatoxins in nuts for compliance with current regulations.

Investigation of total aflatoxin in nuts and dried fruits and consumption habits during pregnancy in Türkiye

Background: During pregnancy, adequate energy, nutrient intake, and food safety are important. Aims: This study aimed to examine the presence of aflatoxin, which has toxigenic properties, in nuts and dried fruits consumed during pregnancy. Subjects and Methods: Forty-five pregnant women living in Istanbul and Balikesir cities provinces, who were selected using the convenience sampling method, were applied face-to-face interview method on their attitudes and behaviors regarding their preferences for consuming nuts and dried fruits and storage conditions between February and April 2022. For aflatoxin analysis, the samples were taken from the nuts and dried fruits consumed by the pregnant women. The total aflatoxin content in the samples was analyzed by the ELISA method with a quantitative aflatoxin high-sensitivity test kit. Results: The most commonly consumed nuts by pregnant women during pregnancy; were walnuts and hazelnuts, respectively. It was determined that pregnant women buy nuts and dried fruits first from the nut shop and second from the market. Regarding storage preferences, it was seen that the participants mostly stored the nuts in the closed kitchen cabinet or refrigerator cabinet. For the storage material preferences, glass, porcelain, and packaging were preferred. For aflatoxin results, no detectable level of aflatoxin was found in 35 samples, and the presence of aflatoxin in 3 samples (1.43 ppb, 1.523 ppb, and 1.804 ppb, respectively) was detected. Conclusion: Nuts and dried fruit consumption preferences of pregnant women differed according to the products. No aflatoxin was found in the nuts and dried fruits at a level that could threaten the health of pregnant women. Keywords: Aflatoxin, Nuts, Dried Fruits, Pregnancy, ELISA method

Fluorine-functionalized covalent organic framework as efficient solid phase extraction sorbent for adsorption of aflatoxins in nuts

In this study, a new fluorine-functionalized covalent organic framework (F-COF) was designed and fabricated by the direct polycondensation of tris(4-aminophenyl)amine and 2,3,5,6-tetra-fluoroterephthaldehyde for the first time. F-COF exhibited a remarkably enhanced adsorption capability compared with that of the fluorine-free COF. The favorable adsorption of aflatoxins was attributed to multiple interactions including pseudo hydrogen bond, F-O, π-π, F-π interactions and hydrophobic interactions between F-COF and aflatoxins. By coupling F-COF based solid phase extraction with high-performance liquid chromatography equipped with fluorescence detector, a rapid and sensitive method for determining aflatoxins (aflatoxin B1, B2, G1 and G2) in nuts (peanuts and pistachios) was established. Under optimal conditions (35 mg F-COF, 100 mL sample solution, 3 mL min−1 as sample loading rate, pH<7, 0.2 mL acetonitrile as desorption solvent), the limits of detection for aflatoxins were 0.02–0.30 ng g−1. The linear range was 0.08–16.0 ng g−1 and the recoveries of the F-COF-based method were 83.5–114 % with relative standard deviations less than 8.0 %.

Occurrence of aflatoxins in nuts and peanut butter imported to UAE

Nuts are an important food group that contributes to maintaining health; however, they can be a source of exposure to aflatoxins. This study was conducted from 2017 to 2021 to assess the incidence of aflatoxins in nuts and nut products imported to the UAE from 57 countries. Associations between container type and processing technique and aflatoxin levels were also analyzed. A total of 5401 samples of pistachios, peanuts, peanut butter, and mixed nuts were examined using HPLC-FLD analysis in conjunction with immunoaffinity cleanup. In nuts, non-conformity was detected in samples imported from 32 different countries. Mean aflatoxin values for the non-compliant samples ranged from 81.0 to 92.7 μg/kg in pistachios, peanuts, and mixed nuts. A significant difference (p < 0.05) was found between mean aflatoxin levels in samples of peanut butter (29.3 μg/kg) compared to the other types of nuts. Nuts packed in containers made of fabric material had the highest mean aflatoxin levels of 108.1 μg/kg, while 29.7 μg/kg was the lowest mean level and was detected in nuts packed in glass. Ground samples had the highest aflatoxin levels (158.9 μg/kg) among processed products. This report will be valuable as a reference document in developing approaches to control nut importation and for establishing procedures that prevent food safety risks due to aflatoxin exposure. A need was underlined for the regulating authority to audit companies importing nuts, ensure safe practices are in place, and establish standards to minimize contamination and prevent the need for product rejection at the border.

Boron-doped activated carbon nanocomposite as a selective adsorbent for rapid extraction of aflatoxins in nut samples

Activated carbon-boron (AC-B) nanocomposite has been developed as a new solid-phase extraction (SPE) sorbent for the extraction and specification of aflatoxins (AFs) in nuts. Porous activated carbon was produced by the chemical activation method from potato peels, which is important biomass waste, and boron was incorporated into the structure. Fourier transform infrared spectroscopy, nitrogen adsorption-desorption, transmission electron microscopy, X-ray diffraction, and scanning electron microscopy methods were used to characterize the adsorbent. The BET specific surface area of AC-B was found to be 1014.7 m2 g−1and the pore volume was 0.42 cm3 g−1. After the extraction parameters (adsorbent amount (1–20 mg), vortex time (1–10 min), pH (3–8), desorption solvent, desorption volume (1–10 ml), and desorption time (1–10 min)) were optimized, recoveries in the range of 89.5–96.5 % of AFG1, AFG2, AFB1, and AFB2 were obtained in real pistachio, cashew nut, and walnut samples. The highest recoveries of AFs were obtained under conditions with AC-B adsorbent amount of 5 mg, vortex time of 3 min, pH 5, desorption solvent acetonitrile, volume 3 ml, and time 3 min. AFs have a low detection limit range (0.04–0.16 μg kg−1). In addition, the method had good repeatability (the intra-day and inter-day RSDs were 0.3–7.0 %, n = 8) and was validated with CRM. The results were evaluated statistically. The proposed AC-B/SPE method has been presented as an alternative to routine analysis due to its advantages such as being environmentally friendly, simple, faster, sensitive, reliable, selective, reproducible, and ease of application in the extraction of aflatoxins compared to the traditional immunoaffinity column method.

The Occurrence of Aflatoxins in Nuts and Dry Nuts Packed in Four Different Plastic Packaging from the Romanian Market.

Mycotoxins are secondary metabolites produced by various fungi. A very important category of mycotoxins are aflatoxins, considered to be the most dangerous in humans. Aflatoxin B1, well known as a favorable factor in the occurrence of hepatocellular carcinoma in humans, is the most controversial of all mycotoxins. Aflatoxins, found in naturally contaminated food, are resistant to degradation by heat. Current food processing practices and conventional storage conditions do not completely eliminate aflatoxin contamination from the food supply chain. Long storage food products—such as peanuts, pistachio, nuts in general, and dried fruits—are susceptible to aflatoxins contamination. The type of plastic material can influence the concentration of aflatoxins during storage due to the permeability to gas and moisture exchange with the external milieu. Nuts in general and dried fruits are consumed in large quantities worldwide. Therefore, herein we investigated the effect of plastic material on the total aflatoxins and aflatoxin B1 content in 64 samples of nuts and dried fruits packed and stored in low-density polyethylene (LDPE), polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET). The method consisted in a cleanup procedure using immunoaffinity columns coupled with RIDASCREEN FAST immunoenzymatic competitive assays based on the ELISA technique. Collected data were subjected to statistical analysis and multiple comparisons tests were applied. From the total analyzed samples, 14.06% exceeded the maximum admitted European levels for total aflatoxins. The highest concentrations of total aflatoxins were obtained from samples packed in LDPE, followed by PP, PE, and PET. Aflatoxin B1 was detected in all samples packed in LDPE, PP, and PE. Most of the samples packed in PET had concentrations <1 µg/kg. These results indicate that nuts in general packed and stored in LDPE are more prone to contamination with aflatoxins, while PET is more suitable for maintaining the quality and safety of these products.

The Effect of Edible Coating Containing Plant Extract on Inhibiting the Growth of Aflatoxin in Nuts

This article is a Letter to Editor and does not include an Abstract.

Evaluation and detoxification of aflatoxins in ground and tree nuts using food grade organic acids

Abstract The contamination of foodstuffs especially nuts with aflatoxins (AFs) affected by some of the fungal genera species is a major threat to the economy, safe food supply and serious health concerns to any country in recent days. Recently different techniques including heat, ozone and microbes are used for the decontamination of aflatoxin but all these are limited to achieve the desirable results. The present study objectives to decontaminate AFs in nuts by using three food-grade organic acids. The aqueous solutions of three food-grade organic acids namely citric, lactic and propionic acid are used at five different concentrations (1, 3, 5, 7 and 9%) to detoxify aflatoxin B1 (AFB1) and total aflatoxins (TAFs) that includes ;AFB1, AFB2, AFG1 and AFG2 in selected nuts including almond, peanut, pistachio and walnut at two different moisture levels (10 ± 3 and 16 ± 3%). The high-performance liquid chromatography (HPLC) coupled with fluorescence detection method was applied for the qualitative and quantitative determination of AFs. The results showed that the decontamination of AFB1 and TAFs significantly increased in infected nuts by increasing the concentration of acids. The experimental results after 15 min treatment of walnut (10 ± 3 and 16 ± 3% moisture level), pistachio (10 ± 3% moisture content) and peanuts (10 ± 3% moisture content) with citric, lactic and propionic acids at 9% concentration significantly reduced AFs about 99, 99.90 and 96.07% respectively. Furthermore, treatment with citric and lactic acids resulted in the conversion of AFB1 into less toxic products identified as AFD1 via hydrolysis of the lactone ring. Furthermore, citric acid was found as the most efficient acid in degrading the TAFs among all three organic acids. The present study showed better AFs detoxification results than conventional methods. Hence, it is concluded that citric, lactic, and propionic acids can be applied as a useful and safe decontamination method for AFB1 and TAFs in aflatoxin-affected nuts.

A Lateral Flow Strip Based on a Truncated Aptamer-Complementary Strand for Detection of Type-B Aflatoxins in Nuts and Dried Figs.

Type-B aflatoxins (AFB1 and AFB2) frequently contaminate food, especially nuts and fried figs, and seriously threaten human health; hence, it is necessary for the newly rapid and sensitive detection methods to prevent the consumption of potentially contaminated food. Here, a lateral flow aptasensor for the detection of type-B aflatoxins was developed. It is based on the use of fluorescent dye Cy5 as a label for the aptamer, and on the competition between type-B aflatoxins and the complementary DNA of the aptamer. This is the first time that the complementary strand of the aptamer has been used as the test line (T-line) to detect type-B aflatoxins. In addition, the truncated aptamer was used to improve the affinity with type-B aflatoxins in our study. Therefore, the lengths of aptamer and cDNA probe were optimized as key parameters for higher sensitivity. In addition, binding buffer and organic solvent were investigated. The results showed that the best pair for achieving improved sensitivity and accuracy in detecting AFB1 was formed by a shorter aptamer (32 bases) coupled with the probe complementary to the AFB1 binding region of the aptamer. Under the optimal experimental conditions, the test strip showed an excellent linear relationship in the range from 0.2 to 20 ng/mL with a limit of detection of 0.16 ng/mL. This aptamer-based strip was successfully applied to the determination of type-B aflatoxins in spiked and commercial peanuts, almonds, and dried figs, and the recoveries of the spiked samples were from 93.3%−112.0%. The aptamer-complementary strand-based lateral flow test strip is a potential alternative tool for the rapid and sensitive detection of type-B aflatoxins in nuts and dried figs. It is of help for monitoring aflatoxins to avoid the consumption of unsafe food.

Analysis of aflatoxins in foods retailed in Saudi Arabia using immunoaffinity column cleanup and high-performance liquid chromatography-fluorescence detection

A liquid–liquid extraction based high performance liquid chromatography-fluorescence method has been proposed for the quantitation of naturally producing aflatoxins in nuts and nut based products. Aflatoxins extraction from nuts and nut products was involved methanol – water extraction, immunoaffinity column cleanup followed by post column derivatization technique. The gel contents of monoclonal antibody of the column are very specific to the toxins of interest, which makes the extraction experiment rapid, simple, highly specific and sensitive. Additionally, the improve concentration of toxins from complex nuts and nut product matrices helps to reduced chromatography interference and lower limit of detection. The proposed method was authenticated to evaluate the performance in terms of linearity of the calibration, limit of detection, recovery, run-to-run (repeatability) and day-to-day precision (reproducibility). Good quality parameters with LOD between 0.003 and 0.007 ppb, recovery from 89 to 98%, linearity in the range of 0.02 to 100 ppb (r2 > 0.989) and precisions with RSDs were achieved below 4.5% at concentration level of 1.0 and 30.0 ppb. The developed method was effectively used to the analysis of aflatoxins (AFB1, AFB2, AFG1, and AFG2) in twenty nuts and nut products and were found up to 120.1 ng/mL AFB1 and 11.2 ppb AFB2 in few of the samples.

Seasonal variation and health implications due to aflatoxins in nuts sold in Riyadh region

This study aimed to assess the health risk from aflatoxins (AF) in nuts commercialized in Riyadh, Kingdom of Saudi Arabia (KSA), across two seasons (summer 2016 to winter 2017). Nut samples including pistachios, walnuts, cashews, and almonds, were analyzed using high-performance liquid chromatography (HPLC) with fluorescence detection. For samples collected in summer, the highest ranges were found in pistachios (0.35–7.13μg/kg), walnuts (0.50–4.39μg/kg), cashews (0.21–1.40μg/kg) and almonds (0.05–1.04μg/kg). AFs were detected in 30 (67%) of the summer samples, with a mean concentration of 1.00±1.25μg/kg. For samples collected in winter, the highest ranges were found in pistachios (0.26–10.76μg/kg), cashews (0.16–2.08μg/kg), almonds (0.25–1.56μg/kg), and walnuts (0.27–1.14μg/kg). AFs were detected in 39 (100%) of the winter samples, with a mean concentration of 1.05±1.66μg/kg. All the samples analyzed had AF levels below the Saudi regulatory limit of 20μg/kg. However, estimation of the margin of exposure and risk of hepatocellular carcinoma (HCC) revealed that pistachio and walnut, particularly in summer, may pose health risks to consumers. Further, the total AF content of three samples exceeded the limit stated in European regulations.

Functional role of selenium-fortified yogurt against aflatoxin-contaminated nuts in rats

BackgroundAflaxions are a group of chemically toxic fungal metabolites produced by species of the genus Aspergillus. Nuts can be contaminated by fungi, resulting in the production of mycotoxins. The present study was performed to investigate the ability of selenium-fortified yogurt to counteract the adverse effects of consuming 3% experimental nuts (pistachios, cashews, walnuts, almonds and hazelnuts) contaminated with aflatoxins in experimental rats. First, the total aflatoxins concentrations were estimated in fresh nuts, and in nuts after 6 months of storage, and selenium-fortified yogurt was prepared. Rats were classified into a negative control group (fed a standard diet with a 3% mixture of fresh safe nuts), a positive control group (fed a standard diet with a 3% mixture of nuts contaminated with aflatoxins after storage at 25 °C for 6 months) and treated groups that fed on pistachios with selenium-fortified yogurt, cashews with selenium-fortified yogurt, walnuts with yogurt fortified with selenium, almonds with selenium-fortified yogurt and hazelnuts with selenium-fortified yogurt (fed a standard diet with 3% individual nuts contaminated with aflatoxins and 160 ml/kg body weight of selenium-fortified yogurt daily through a stomach tube).ResultsThe negative effects of aflatoxins on weight gain and food intake were reversed by selenium-fortified yogurt. This yogurt also led to a significant decrease in serum cholesterol, TG, LDLc, VLDLc, total lipids, phospholipids, glucose and atherogenic indexes (CHO/HDLc and LDLc/HDLc) and an increase in serum HDLc, haemoglobin, PCV, liver TG and glycogen at p < 0.05. In addition, the study showed a significant decrease in liver cholesterol and total lipids compared to the positive control rat group, which consumed 3% mixed nuts contaminated with aflatoxins and simultaneously restored these parameters to be close to those in the control group. The results were corroborated by histopathological examination of the liver and kidneys.ConclusionsThe most prominent conclusion is that selenium-fortified yogurt reduces side effects from consumption of nuts contaminated with aflatoxins. It is recommended to consume functional selenium-fortified yoghurt for its nutritional values and for alleviating the harmful effect of aflatoxins in nuts.

Determination of aflatoxins in nuts of Tabriz confectionaries by ELISA and HPLC methods.

Aflatoxins (AFs) are a group of mycotoxins and secondary metabolites of various species of Aspergillus. There are various forms of aflatoxins including B1, B2, G1, G2, M1 and M2 types. Aflatoxins cause important health problems and have high potential effect on liver cancer. Therefore, numerous investigations have been conducted during last three decades. The aim of this work is to determine the contamination levels of nuts used by the confectionaries in Tabriz. A total of 142 samples including 35 almond , 26 walnut, 4 seeds of apricot, 6 sunflower seeds kernel, 6 sesame seed, 6 peanuts , 32 pistachio,13 hazelnuts and 14 cashews samples were collected from Tabriz confectionaries. The ELISA method was employed for the screening of total aflatoxins. In 13 cases (28.1% of pistachios, 5.1% of walnuts and 7.1% of cashews) contamination rate of higher than 15 ppb were observed. The HPLC method was applied for the confirmation of ELISA results. Aflatoxin B1 was the highest detected AFs. The overall results of the tested samples indicated that the rate of contamination of pistachios is higher than the other tested samples.

Determination of aflatoxins in commercial nuts and nut products using liquid chromatography tandem mass spectrometry

A rapid and sensitive confirmatory analytical method for determination of aflatoxins in nuts and their products using liquid chromatography tandem mass spectrometry has been developed and validated. All four aflatoxins of interest (B1, B2, G1 and G2) were quantified using aflatoxin M1 as the internal standard. Samples were extracted using methanol/water (60:40, v/v) and cleaned-up with immunoaffinity column. Limit of detection ranged between 0.10 and 0.30 µg/kg. Recovery rates were between 76 and 105% for all analytes. For further validation, a reference material for contaminated peanut has been used for quality assurance measures to check the accuracy and precision. The method was successfully applied to determine the natural occurrence of aflatoxins in 128 nut samples marketed in Penang, Malaysia. More than half of the samples (57.0%) were positive and 13.3% were found to be non-compliant with the European Commission regulations permitted maximum level of 2 µg/kg for aflatoxin B1. The contamination levels ranged from 0.40 to 221.61 µg/kg for aflatoxin B1 and 0.33 to 273.63 µg/kg for total aflatoxins.

Application of pressurized liquid extraction in the analysis of aflatoxins B1, B2, G1 and G2 in nuts

Aflatoxins (AFs) B(1), B(2), G(1) and G(2) were extracted from nuts by using pressurized liquid extraction (PLE) and the PLE extracts were analyzed using HPLC with fluorescence detection using photochemical post-column derivatization without further cleanup procedures. Several extraction parameters such as temperature (25, 40, 60 and 80 degrees C), pressure (500, 1000, 1500 and 2000 psi), solvent extraction mixture (acetone, acetonitrile, ethyl acetate and methanol), number of cycles (1 and 2), use of dispersing agents and cell size (5 and 11 mL) were investigated for their effects on the extraction performance. The results showed 60 degrees C, 1500 psi, acetonitrile, one cycle and a cell size of 5 mL as most favorable PLE operating conditions. The proposed analytical method provides LODs below the maximum levels established by European Union regulations and the recoveries of the four AFs were between 77 and 93% at spiking levels of 4, 2 and 0.5 microg/kg for AFB(1) and AFG(1) and 1, 0.5 and 0.13 microg/kg for AFB(2) and AFG(2). Validation was carried out using certified reference materials. PLE has been applied for the first time to the analysis of AFs in nuts and offers the possibility for fast simple and accurate quantitative determination of studied mycotoxins.

OCCURRENCE OF AFLATOXINS IN VARIOUS NUTS COMMERCIALIZED IN TURKEY

ABSTRACT Nuts are important agricultural commodities in Turkey as they are exported and largely consumed domestically. Two hundred and seventeen samples of hazelnuts, pistachio nuts and peanuts were randomly collected from public markets, bazaars, supermarkets and retail stores in several regions of Turkey and analyzed for the incidence of aflatoxin (B1, B2, G1, G2) contamination by high‐performance liquid chromatography. The levels of aflatoxin B1 (AFB1) and the total aflatoxins in the majority of samples analyzed (87.09%) were so low that they were not quantifiable. Thirty‐one samples (14.28%) were found to have low levels of aflatoxins, below the Turkish National regulatory limits of 5 µg/kg for AFB1 and 10 µg/kg for total aflatoxins. However, four samples (1.84%) showed a level of contamination that exceeded the maximum tolerated levels set in the Turkish regulations. The highest value of AFB1 was 36.81 µg/kg in pistachio nuts. This article reports the data of the first survey on the presence of aflatoxins in nuts sampled in three distinct regions of Turkey. PRACTICAL APPLICATIONSThe formation of aflatoxins depends not only on the genetic potential of mold strains but also on environmental factors, especially during post‐harvest transportation and storage. Although further national surveys must be performed on a regular base, the results of the present study indicate a reduced level of aflatoxin contamination of nut‐based products compared to earlier observations. The results conclude that implementation of stricter quality control measures, technical assistance to private sector actors and regulatory initiatives to support employment of these strategies undertaken in recent years by the National Authorities have paid back.

Growth of aflatoxigenic moulds and aflatoxin formation in Brazil nuts

The present study aimed at gaining more knowledge of the growth of aflatoxigenic moulds and aflatoxin production in Brazil nuts in relation to humidity conditions and storage time. For this purpose, the growth of aflatoxigenic moulds and the increase in aflatoxin levels in Brazil nuts was studied in the laboratory at temperature and humidity conditions that are relevant for the Amazon region. Fresh unprocessed Brazil nuts in shell were inoculated with an aflatoxin producing strain of Aspergillus nomius previously isolated from Brazil nuts. The nuts were stored at 27 °C in combination with 97, 90 or 80% surrounding relative humidity in a respirometer for up to 3 months. The General Linear Model (GLM) was used for evaluation of the effect of water activity and time on aflatoxigenic mould levels and on aflatoxin levels, as well as the relationship between mould and aflatoxin levels. During storage at the highest relative humidity (97%) aflatoxin formation occurred rapidly, whereas storage at 90% relative humidity resulted in slower aflatoxin formation. At the lowest relative humidity (80%), aflatoxin formation occurred sporadically during storage. The increase in mould and aflatoxin levels along the production chain is also described, using field data collected in the state of Para, Brazil. The growth of aflatoxigenic moulds and aflatoxin formation increased rapidly between 40-90 days following collection of the nuts, before the nuts reached the final drying stage at the processing plant. In addition, a logistic regression model predicting the probability that the European legislative limit of 4 µg/kg for aflatoxins in nuts will be exceeded in relation to colony counts of either one selected aflatoxigenic mould strain (laboratory experiments) or of a mixture of aflatoxigenic strains (field data) was developed. The probability that total aflatoxin levels will exceed the European legislative limit of 4 µg/kg increased rapidly from approx. 30% to above 80% for both experimental and field samples at mould levels between 2 and 3 log cfu/g.