Amperometric biosensor for aflatoxin B1 based on aflatoxin-oxidase immobilized on multiwalled carbon nanotubes

An amperometric aflatoxin biosensor developed by aflatoxin-oxidase (AFO), embedded in sol-gel, linked to multiwalled carbon nanotubes (MWCNTs)-modified Pt electrode was reported for the first time. The covalent linkage between AFO and MWCNTs retained enzyme activity and responsed to the oxidation of afltoxin B₁ (AFB₁). Its apparent Michaelis-Menten constant for AFB₁ was 7.03 μmol·L^?1, showing a good affinity. The sensor exhibited a linear range from 3.2 nmol·L^?1 to 721 nmol·L^?1 (1 ng/ml to 225 ng/ml) with limits of detection of 1.6 nmol·L^?1 (signal-to-noise ratio = 3), an average response time of 44 s (less than 30 s when AFB₁ Conc. is bigger than 45 ng/ml), and a high sensitivity of 0.33 × 10² A mol^?1·L cm^?2. The active energy was 18.8 kJ mol^?1, demonstrating the significant catalyzation of AFO for oxidation of AFB₁ in this biosensor.     

Isolation and characterization of a Bacillus subtilis strain with aflatoxin B1 biodegradation capability

Aflatoxins are type of mycotoxins mainly produced by Aspergillus flavus and a common contaminant of food and grain, posing a serious economic and health problem worldwide. In order to find efficient bacteria to remove or detoxify these mycotoxins, a bacterial strain capable of degrading aflatoxin B₁ (AFB₁) was isolated from soil samples using a culture medium containing coumarin as the sole carbon source. Based on 16S rRNA gene sequence analysis, this isolate was identified as Bacillus subtilis JSW-1; its further characterization showed that it could inhibit the growth of A. flavus with an inhibition ratio of 58.3% and could degrade AFB₁ by 67.2% after incubation at 30 °C for 72 h. The aflatoxin B₁-degrading activity of isolate JSW-1 was predominantly attributed to the cell-free supernatant and this activity was found to be heat stable but sensitive to proteinase K treatment, indicating that the extracellular proteins or enzymes are responsible for the AFB₁ degradation. In addition, no degradation products of AFB₁ could be detected by liquid chromatography-mass spectrometry (LC-MS) analysis, indicating that the parent AFB₁ might be biotransformed to compounds with chemical properties different from that of AFB₁.     

Aflatoxin contamination of dried red chilies: Contrasts between the United States and Nigeria,two markets differing in regulation enforcement

Dried red chilies are among the world’s most consumed spices. From farm to fork, chilies go through cropping, harvest, drying, processing and storage. Chilies are susceptible to infection by aflatoxin producing fungi and subsequent contamination by aflatoxins at every stage. Aflatoxins are highly regulated, hepatotoxic carcinogens produced by fungi in Aspergillus section Flavi. The current study examined prevalence of aflatoxin B₁ (AFB₁) in chilies from markets across the United States (US) and Nigeria, and determined predisposition of chilies to aflatoxins post-harvest. Aflatoxin B₁ was detected in 64% chilies from US markets (n = 169), and 93% of Nigerian chilies (n = 55) with a commercial lateral flow assay (Limit of Detection = 2 μg/kg). Two percent of US samples exceeded the aflatoxin regulatory limit of 20 μg/kg, while the highest concentration detected was 94.9 μg/kg. Aspergillus spp. could be recovered only from 40% of samples from the US, and aflatoxin levels did not correlate with quantities of Aspergillus section Flavi (Colony Forming Units g⁻¹), suggesting fungi associated with chilies in US markets were killed during processing. Both average AFB₁ concentrations and fungal quantities were significantly higher (p < 0.01) in Nigerian chilies. The most contaminated sample contained 156 μg/kg AFB₁. Aflatoxin concentrations in Nigerian chilies increased as an exponential function of the quantities of Aspergillus section Flavi (r² = 0.76). Results indicate that high rates of chili consumption may be associated with unacceptable aflatoxin exposure.     

Development of an aptasensor for the fast detection of Versicolorin A

Aflatoxins (AFs) are secondary metabolites produced by Aspergillus flavus and Aspergillus parasiticus. The molds may contribute to pre-harvest aflatoxin contamination of susceptible crops. For the customer and food producer, a predictive model for aflatoxin detection is very desirable. Versicolorin A (VerA), which is the first precursor in the pathway of aflatoxin B₁ (AFB₁) biosynthesis, shares similar toxic group with the furofuran structure in aflatoxin B₁. VerA exhibits a much lower teratogenic toxicity than AFB₁ and may be used as a predictive indicator for aflatoxin B₁ contamination of storage crops. Therefore, the development of a fast detection method for VerA is important. One of the randomly computer-generated aptamers of VerA was confirmed by isothermal titration calorimetry with K_d = 9.26 × 10⁻⁶ mol l⁻¹. In addition, a simple and sensitive label-free aptasensor was developed for the electrochemical detection of VerA. According to the results from differential pulse voltammetry (DPV), a linear relationship existed between the log conc. of VerA (ranged from 0.01 to 100 ng ml⁻¹) and the current (△I_p) with a limit of detection (LOD) of 10 pg ml⁻¹. The resulting aptasensor exhibited good reproducibility for detecting VerA and stability after storage for 15 days at 4 °C with acceptable anti-interference against ZEN, OTA, DON, and FB₁. When used in corn samples, the recoveries of VerA were determined to be in the range of 81.3%–104.4 %. Although with some intercross, result suggests that the obtained aptamer for VerA is potentially used as a sorbent for the preparation of solid-phase-extraction procedure to clean up food samples in conjunction with high-performance liquid chromatography analysis.     

Removal of aflatoxin B1 by roasting with lemon juice and/or citric acid in contaminated pistachio nuts

Nowadays, aflatoxin B₁ (AFB₁) could be considered as one of the most hazardous mycotoxins for humans, and nuts comprise one of the major responsible food categories for human exposure to this mycotoxin. Thus, complete elimination of AFB₁ or reduction of its content in nut foods, such as pistachio attracted lots of attentions. In the current study, the efficacy of roasting process by incorporation of lemon juice and/or citric acid on the reduction of AFB₁ in contaminated pistachio nuts (AFB₁ at two levels of 268 and 383 ng/g) was investigated. Significant degradation of AFB₁ (up 93.1% for AFB₁) was recorded by applied treatment protocols. Although roasting of 50 g pistachio nuts with 30 ml water, 30 ml lemon juice and 6 g of citric acid at 120 °C for 1 h resulted to a significant degradation (93.1 ± 8.2%) of AFB₁, this treatment altered the desired physical properties. Roasting with 30 ml water, 15 ml lemon juice and 2.25 g of citric acid at 120 °C for 1 h reduced the level of AFB₁ in 49.2 ± 3.5% of the initial level without a noticeable change in desired appearance of pistachios. Hence, a synergistic effect between heating and lemon juice/citric acid in order to AFB₁ degradation was observed. It could be concluded that roasting process with lemon juice and citric acid could be applied as a useful and safe degradation method of AFB₁ in naturally contaminated pistachio nuts.     

Multiple mycotoxin co-occurrence in maize grown in three agro-ecological zones of Tanzania

In this study, the co-occurrence of multiple mycotoxins in maize kernels collected from 300 households' stores in three agro-ecological zones in Tanzania was evaluated by using ultra high performance liquid chromatography/time-of-flight mass spectrometry (TOFMS) with a QuEChERS-based procedure as sample treatment. This method was validated for the analysis of the main eleven mycotoxins of health concern that can occur in maize: aflatoxin B₁ (AFB₁), aflatoxin B₂ (AFB₂), aflatoxin G₁ (AFG₁), aflatoxin G₂ (AFG₂), ochratoxin A (OTA), deoxynivalenol (DON), fumonisin B₁ (FB₁), fumonisin B₂ (FB₂), HT-2 toxin, T-2 toxin and zearalenone (ZEN). From each zone one major maize producing district for home consumption was chosen and 20 villages for each district were randomly selected for sampling. All mycotoxins of health concern, except for T-2 toxin, were detected in the maize samples. Particularly high levels of AFB₁ (50%; 3–1,081 μg kg⁻¹), FB₁ (73%; 16–18,184 μg kg⁻¹), FB₂ (48%; 178–38,217 μg kg⁻¹) and DON (63%; 68–2,196 μg kg⁻¹) were observed. Some samples exceeded the maximum limits set in Tanzania for aflatoxins or in European regulations for other mycotoxins in unprocessed maize. Eighty seven percent of samples were contaminated with more than one mycotoxin, with 45% of samples co-contaminated by carcinogenic mycotoxins, aflatoxins and fumonisins. Significant differences in contamination pattern were observed among the three agro-ecological zones. The high incidence and at high levels (for some) of these mycotoxins in maize may have serious implications on the health of the consumers since maize constitute the staple food of most Tanzanian population. Effective strategies targeting more than one mycotoxin are encouraged to reduce contamination of maize with mycotoxins.     

Degradation of AFB1 in aqueous medium by electron beam irradiation: Kinetics,pathway and toxicology

The degradation study of aflatoxin B₁ (AFB₁) in aqueous medium was performed under electron beam irradiation (EBI) at various AFB₁ initial concentrations. It has been proven that the degradation of AFB₁ in the selected ranges of concentrations follows pseudo first-order reaction kinetics well (R² > 0.95). Five degradation products of AFB₁ in aqueous solution were identified by UPLC-Q-TOF/MS, and the possible degradation pathway was proposed. The Ames and cytotoxicity tests were employed to evaluate the toxicity of the AFB₁ degradation products in aqueous solution, and the results indicated that the mutagenicity and cytotoxicity of EBI treated samples decreased significantly compared with that of untreated samples, but were not completely disappeared. The study provided clues involving the application of EBI methods in AFB₁ decontamination.     

Effectiveness of pulsed light treatment for degradation and detoxification of aflatoxin B1 and B2 in rough rice and rice bran

Aflatoxins primarily accumulate in the hull and bran layers of rough rice making these by-products of rice milling unsuitable for animal feed or human consumption. Contaminated rough rice is also a potential source of aflatoxin exposure to workers handling the grain during post-harvest storage and processing. Currently, no technologies are available to remove or detoxify these toxic and mutagenic fungal metabolites from contaminated rough rice. Pulsed light (PL) is a novel technology with the potential to degrade and detoxify aflatoxins in foods and their processing by-products. Rough rice was inoculated with Aspergillus flavus to produce aflatoxin B₁ (AFB₁) and B₂ (AFB₂) contamination, followed by PL treatments of 0.52 J/cm²/pulse for various durations. A PL treatment time of 80 s reduced AFB₁ and AFB₂ in rough rice by 75.0% and 39.2%, respectively; while a treatment time of 15 s reduced AFB₁ and AFB₂ in rice bran by 90.3% and 86.7%, respectively. Since PL treatments result in the degradation of aflatoxins in situ, the toxicity and mutagenic activity of the residual by-products of AFB₁ and AFB₂ after PL treatment were evaluated. Toxicity was estimated using the brine shrimp (Artemia salina) lethality assay and mutagenicity measured by the fluctuation test with Salmonella typhimurum tester strains TA98 and TA100. The mutagenic activity of AFB₁ and AFB₂ was completely eliminated by PL treatment, while the toxicity of these two aflatoxins was significantly decreased. The obtained results suggest that PL technology has a promising potential to degrade, detoxify, and inactivate the mutagenic activity of aflatoxins in rough rice and rice bran.     

Effect of ozone treatment on aflatoxin B1 and safety evaluation of ozonized corn

This paper studies the ozone treatment effect on degradation of aflatoxin B₁ (AFB₁) in corn with different moisture content (MC). The toxicity of the degradation products (DPs) of the ozone-treated AFB₁-Contaminated Corn (ACC) was also evaluated using the human hepatocellular carcinoma cell line (HepG2) as model cells. The degradation rate of AFB₁ in corn increases with ozone concentration and treatment time. The results showed that ACC with 13.47% MC was easier to be degraded by ozone than with 20.37% MC. Treated with 90 mg L⁻¹ ozone for 20 min and 40 min, AFB₁ in corn with 13.47% MC decreased from 83 μg kg⁻¹ to 18.12 μg kg⁻¹ and 9.9 μg kg⁻¹, respectively, well meeting the China National Standard of AFB₁ in corn (20 μg kg⁻¹). In order to evaluate the safety of ozone used on ACC, the impacts of AFB₁ as well as untreated and ozone-treated ACC with the same level of AFB₁ content on HepG2's survival rate, morphology, and apoptosis were studied. The results showed that ACC had high cell toxicity while the toxicity of ozone-treated ACC had no significant difference with that of the AFB₁-free culture solution. It is concluded that ozonation can quickly and effectively degrade AFB₁ in corn and diminish ACC's toxicity, and therefore, ozonation is expected to be an effective, fast, and safe method for AFB₁ degradation in ACC.     

Evaluation of latex agglutination inhibition reaction test for rapid detection of aflatoxin B1

Aflatoxin B₁ (AFB₁), a mycotoxin mainly produced by some Aspergillus species, has been found in a wide range of agricultural products. To avoid the risk of AFB₁ consumption, many agricultural commodities, foods and feeds should be analyzed and a rapid and non-instrumental method for the detection of AFB₁ is needed. In this study, a rapid, inexpensive and user-friendly latex agglutination inhibition reaction test (LAIRT) for on site testing of AFB₁ had been established. At first, carboxylated polystyrene latex particles (CPLP) were prepared by soap-free polymerization and sensitized with aflatoxin B₁ oxime-BSA (AFB₁O-BSA) for the detection of AFB₁. In LAIRT, the agglutination reaction with AFB₁O-BSA-sensitized CPLP and anti-AFB₁ antiserum mixture was inhibited by 5 ng/mL AFB₁ and the analysis time for 6 samples on one glass slide was less than 10 min. Subsequently, 10 rice and peanut samples were analyzed by LAIRT and ELISA, and the results showed that 1 rice sample and 2 peanut samples were positive and in agreement with those of ELISA. However, the results could be obtained more rapidly by LAIRT than ELISA. This easy and rapid LAIRT might be useful for screening AFB₁ of agricultural commodities, foods and feeds in the field.     

Development and validation of an accurate and rapid LC-ESI-MS/MS method for the simultaneous quantification of aflatoxin B1, B2, G1 and G2 in lotus seeds

An accurate and rapid LC-ESI-MS/MS analytical method was developed and validated for the simultaneous determination of aflatoxin B₁, B₂, G₁ and G₂ in lotus seeds. The samples were firstly extracted with methanol-water solution (80:20, v/v), and then cleaned up by immunoaffinity columns. The mass spectrometer was operated in the positive ionization electrospray (ESI+) mode using multiple reaction monitoring (MRM) for analysis of four aflatoxins. The transitions of m/z 313 → 285 (AFB₁, CE 33 eV), m/z 315 → 259 (AFB₂, CE 37 eV), m/z 329 → 243 (AFG₁, CE 37 eV) and m/z 331 → 257 (AFG₂, CE 37 eV) were used to quantify these four aflatoxins, respectively. The limits of detection (LODs) of aflatoxin B₁, B₂, G₁ and G₂ were 0.007, 0.005, 0.003 and 0.005 μg kg^?1 based on a signal-to-noise ratio of 3:1, respectively. The limits of quantification (LOQs) of aflatoxin B₁, B₂, G₁ and G₂ were 0.02, 0.015, 0.01 and 0.015 μg kg^?1 based on a signal-to-noise ratio of 10:1, respectively. Recoveries for samples of spiked lotus seeds were all above 66% with relative standard deviation all below 15% for all compounds. Nineteen out of twenty batches of lotus seeds collected from different drug stores or markets in China were found to be contaminated with aflatoxins at different levels ranging from 0.02 to 688.4 μg kg^?1.     

Annual and regional variations of aflatoxin B1 levels seen in grains and feed coming from Croatian dairy farms over a 5-year period

The aim of the study was to investigate annual and regional differences in the level of aflatoxin B₁ (AFB₁) in grains and dairy cattle feed. Maize (n = 972), wheat (n = 201), barley (n = 147), oat (n = 136), grain mixtures (n = 168), and dairy cattle feed (n = 325) were sampled from 2009 to 2013 on different farms and in different farm factories situated in four Croatian regions. The samples were analysed for AFB₁ using the validated ELISA immunoassay. AFB₁ was determined in 16.4% of all investigated samples, among which maize was proven to be the most contaminated, with 21.7% of the samples recovered during 2013 harbouring AFB₁ in concentrations over the permissible ones. Levels higher than permitted were observed in 17.9% and 12.3% of grain mixtures and dairy cattle feed, respectively, whereas concentrations of AFB₁ determined in other crops throughout the investigated period met the stipulated requirements. The results revealed the AFB₁ occurrence to be significantly (p < 0.05) dependent on the cultivation region, with the highest levels generally found in maize harvested in 2013 and consequently in grain mixtures and cattle feed that can most likely be associated with climatic conditions as the most critical factor for mould formation, and thus also AFB₁ production.     

Aflatoxin contamination level in Iran's pistachio nut during years 2009–2011

An efficient monitoring system for sampling, analyzing and issuing the export certificates for pistachio consignments has been established in Iran in recent years. Accordingly, 3181 commercial raw pistachio nut lots were supplied for testing for European export certification since January 2009 till December 2011. Aflatoxin analysis was carried out by high-performance liquid chromatography with fluorescence detection after immunoaffinity column clean up with recoveries ranging from 77 to 99%. Amongst 8203 sub-samples analyzed, aflatoxin B₁ (AFB₁) was detected in 1921 cases (23.4%) with the mean and median values of 2.18 ± 13.1 ng/g and <LOD, respectively. Total aflatoxin (AFT) was detected in 1927 sub-samples (23.5%) with the mean and median values of 2.42 ± 14.7 ng/g and <LOD, respectively. AFB₁ level in 556 (6.78%) and 428 (5.22%) sub-samples was above the maximum tolerable levels set for AFB₁ in Iran (5 ng/g) and European Union (EU) (8 ng/g). The mean contamination levels of AFB₁ (2.18 ng/g) and AFT (2.42 ng/g) were lower than the maximum tolerable levels set in Iran and EU. The contamination levels of pistachio nut for export to EU were ∼50% of those found in 2002–2003 indicating a satisfying improvement in hygienic conditions of pistachio cultivation, harvesting and post-harvesting practices in Iran.     

Highly sensitive toxin microarray assay for aflatoxin B1 detection in cereals

We report a rapid, highly sensitive microarray method for quantitative aflatoxin B₁ (AFB₁) detection in cereal samples. Following optimisation using an indirect competitive immunoassay, optimised amounts of AFB₁-bovine serum albumin (AFB₁-BSA)-conjugate were contact-printed onto 16 isolated sub-arrays on multi-pad nitrocellulose coated slides subsequently used in competitive binding assays.The toxin microarray working range for AFB₁ was established in the range of 15 pg g⁻¹ to 3.04 ng g⁻¹, with a detection limit of 1 pg g⁻¹. To determine assay sensitivity in contaminated food models, wheat flour and barley grains samples were spiked with AFB₁ standard dilutions. Following extraction, the working ranges of 0.11–4.15 and 0.18–4.31 ng g⁻¹ were determined, with detection limits of 30 and 90 pg g⁻¹, respectively. The sensitivity of the developed assay is below the European commission limit set for AFB₁ detection and the assay procedure was completed in 3 h time. Good recoveries (98% ± 11%) obtained demonstrate the suitability of the proposed method for rapid and sensitive quantification of AFB₁ in contaminated cereal samples.     

Aflatoxin B1 in post-harvest peanuts and dietary risk in China

To monitor the aflatoxin contamination status in raw peanuts and evaluate the effect on public health, 1040 samples were collected from four agro-ecological zones throughout 12 provinces from 2009 to 2010 in China and then analyzed for aflatoxin B₁ (AFB₁) levels using High Pressure Liquid Chromatography (HPLC) and immunoaffinity columns. The results revealed that AFB₁ was detected in 25% of the samples, ranging from 0.01 to 720 μg/kg. The Monte Carlo and bootstrap methods were employed to estimate AFB₁ intake in children and adults and their potential liver cancer risk. The mean estimated intakes for children and adults were 0.218-0.222 ng/kg body weight (bw)/day and 0.106-0.108 ng/kg bw/day. The liver cancer risk, calculated by two approaches derived from the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and European Food Safety Authority (EFSA), were estimated at 0.003-0.17 cancer cases/year/100,000 and 24.7-1273 margins of exposure values, respectively. The results suggest that AFB₁ contamination in raw peanuts and dietary risk was low, but essential surveillance measures should be taken to protect public health.     

Aflatoxin B1 degradation by culture and lysate of a Pontibacter specie

The presence of aflatoxin B₁ (AFB₁) along the food chain poses a significant threat, thus propelling the need for an effective approach to control it. This study was therefore, aimed at investigating AFB₁ degradation of liquid cultures and lysates of an isolated Pontibacter sp. (VGF1). Liquid cultures, lysed bacterial cells in the absence (uninhibited lysates) and presence of protease inhibitors (protease inhibited lysates) were respectively incubated with AFB₁ for 3, 6, 12, 24 and 48 h. AFB₁ degradation was monitored during this period on high performance liquid chromatography (HPLC) and results obtained revealed that after 6 h of incubation, the protease inhibited (PI) lysates yielded a 65% AFB₁ degradation, whereas after 12 h, no residual AFB₁ was detected. Conversely, after 48 h of incubation, a significantly (p≤0.05) lower AFB₁ degradation of 50 and 36% by the liquid culture and uninhibited lysate, respectively, were noted. It was further confirmed that the degradation mechanism was enzymatic. Data from cytotoxicity studies against human lymphocytes further demonstrated that extracts of biotransformed AFB₁ were less toxic when compared to that of AFB₁. Findings from this study have demonstrated an alternative approach for the decontamination and biocontrol of AFB₁ in various agricultural commodities.     

Degradation and detoxification of AFB1 by Staphylocococcus warneri,Sporosarcina sp. and Lysinibacillus fusiformis

Effects associated with aflatoxins (AFs), principally aflatoxin B₁ (AFB₁) have necessitated strategies to eliminate their occurrence in commodities along the food chain. This study therefore, investigated the AFB₁ biodegradation ability of Staphylococcus warneri, Sporosarcina sp. and Lysinibacillus fusiformis liquid cultures and cell lysates (disrupted in the presence or absence of protease inhibitors to obtain lysates). These were incubated with AFB₁ (2.5 μg/mL) for 3, 6, 12, 24 and 48 h. AFB₁ degradation was subsequently monitored on high performance liquid chromatography (HPLC) and results indicated that after 48 h, % AFB₁ degradation by the liquid cultures of Lysinibacillus fusisormis, S. warneri and Sporosarcina sp. were 61.3, 47.7 and 46.9%, respectively. After 12 h of incubation, a 100% AFB₁ degradation was observed for all protease inhibited lysates tested. To establish toxicity of the AFB₁ biotransformed products, results from a cytotoxicity study against human lymphocytes demonstrated that the products exhibited significantly (p ≤ 0.05) lower cytotoxic effect compared to the parent AFB₁. From this study, it can be deduced that the mechanism of AFB₁ degradation was enzymatic and that protease inhibition of cells before disruption, could increase this enzymatic activity. Conclusively, the potential of these lysates as a biotechnological approach towards decontaminating AFB₁ is promising.     

Incidence and consumer awareness of toxigenic Aspergillus section Flavi and aflatoxin B1 in peanut cake from Nigeria

Peanut cake samples were collected from major markets in five states of Nigeria and evaluated for incidence of toxigenic Aspergillus section Flavi populations, and aflatoxin B₁ (AFB₁) levels by liquid chromatography tandem mass spectrometry (LC–MS/MS). The awareness of consumers to the presence of aflatoxin in the snack and potential health risks of its regular ingestion was evaluated by questionnaire analysis. Aspergillus section Flavi populations were recovered from 83% of the peanut cake samples. Aspergillus flavus L-strain was the most predominant (>56%) across the states while Aspergillus tamarii had the least mean incidence (2.7%). The incidence of atoxigenic strains was significantly (p < 0.05) higher than that of toxigenic strains in samples from Lagos and Kaduna, while the toxigenic strains had a significantly (p < 0.05) higher incidence than the atoxigenic strains in Niger. All analyzed cake samples contained AFB₁ in concentrations exceeding the NAFDAC recommended level for AFB₁ in food and reaching up to 2824 μg/kg. There was a weak positive correlation (r = 0.32, p = 0.03) for the relationship between the incidence of toxigenic strains in the samples and AFB₁ concentration. The consumer awareness data showed that 64% of the respondents consumed peanut cake; majority of who are youth of economic and reproductive age. Eighty-five percent of the consumers lacked awareness of aflatoxin contamination in the snack and possible health risks associated with its ingestion.     

Aflatoxin B1 occurrence in maize sampled from Croatian farms and feed factories during 2013

The aim of the study was to determine the level of aflatoxin B₁ (AFB₁) in maize sampled from farms and feed factories situated in Northern, Central and Eastern Croatia during 2013, following the occurrence of cow milk AFM₁ contamination. Maize samples (n = 633) were analysed using Enzyme-Linked Immunosorbent Assay (ELISA) as a screening method and High Performance Liquid Chromatography Tandem Mass Spectrometry (LC–MS/MS) as a confirmatory method. Mean AFB₁ value found in maize coming from all investigated regions equalled to 81 μg/kg, with the maximal value of 2072 μg/kg found in maize obtained from Eastern Croatia. The observed contamination might have arisen on the grounds of extremely hot (>98%) and dry (<2%) weather witnessed from May to September 2012 during the maize growth and harvesting period, which might have favoured AFB₁ production and consequently the contamination of dairy cattle feeds. In order to prevent the adverse effects of AFB₁ on humans and animals, and also to reduce losses in agricultural production, systematic monitoring and further investigations of AFB₁ contamination are necessary.     

Survey of aflatoxin B1 in helva,a traditional Turkish food,by TLC

A total of 102 helva samples consisting of 34 plain helva, 34 helva containing cacao, and 34 helva containing pistachio nuts purchased from helva-factories and supermarkets in Adana of Turkey were analysed for aflatoxin B₁ (AFB₁) by thin-layer chromatography. The detection limit of AFB₁ was 1 μg kg⁻¹. Recovery experiments were carried out with spiked samples in the range 2–10 μg kg⁻¹ of AFB₁. No AFB₁ was found in any plain helva and helva containing cacao samples. On the other hand, of 34 helva containing pistachio nuts AFB₁ was determined in eight samples. AFB₁ was found in excess of Turkish legal limit of 5 μg kg⁻¹ in 4 of 102 helva samples. This paper reports the data of the first survey for the presence of AFB₁ in helva in Turkey.