Development of a sensitive competitive indirect ELISA method for determination of ochratoxin A levels in cereals originating from Nanjing,China

A monoclonal antibody against ochratoxin A (OTA) was produced and a simple, rapid and reliable competitive indirect ELISA (ci-ELISA) for detection of OTA was developed. The 50% inhibitory concentration (IC₅₀) was 1.70 ng/mL, with a detectable range of 0.55–6.75 ng/mL, and a limit of determination (LOD) at 0.15 ng/mL. The cross-reactivity of the antibody against ochratoxin B was 17%, and <10% against deoxynivalenol, fumonisin B₁ or aflatoxin B₁. A survey of 65 cereal samples was carried out in Nanjing, the capital of Jiangsu Province, China. The frequencies of OTA contamination were 36.36%, 26.08% and 15.00%, and the mean concentrations of positive samples were 4.248 ng/g, 7.360 ng/g and 3.382 ng/g for wheat, corn and rice, respectively. The results of this study suggest that the ci-ELISA developed can be used to determine OTA in agricultural commodities such as cereals, and a survey might be needed to investigate OTA contamination in food and feed to prevent their harmful health effects.     

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.     

Levels of selected pesticides in honey samples from Kahramanmaraş, Turkey

In this study 32 pesticide residues and eight polybrominated diphenlyl ether (PBDE) congeners were measured in nine honey samples from Kahramanmaraş, Turkey. A new method based on the best recovery was column extraction with n-hexane/acetone followed by gas chromatography electron-capture detection (GC-ECD), and mass spectrometry (GC–MS). Generally the pesticide levels were low in the honey samples. γ-HCH and PCB 28 were being measured in all honey samples. The sum of HCHs in samples varied between 0.71 and 2.47 ng/g. Malathion, bromophos methyl, cis-HCE, chlordane, endrin, p,p′-DDE and o,p′-DDD were not detectable. The mean values of α-HCH and β-HCH were 0.60 and 0.52 ng/g. The mean values of HCB, α-chlordan, trans-nonachlor, cis-nonachlor, Heptachlor, aldrin, bromophos ethyl, trans-HCE, α-endosulfan, β-endosulfan, dieldrin were 0.30, 0.05, 0.14, 0.84, 0.04, 0.06, 2.74, 0.03, 0.09, 0.27, 0.36 ng/g respectively. In none of the samples PBDEs were detected.     

Monitoring of selected aflatoxins in brewing materials and beer by liquid chromatography/mass spectrometry

In 2008-2011 a total set of 333 samples of brewing raw materials and beer were analyzed for the presence of aflatoxins B₁, B₂, G₁ and G₂. The standard analytical method using high-performance liquid chromatography coupled to mass spectrometric detection with immunoaffinity column clean-up was applied. The method was validated. Limits of detection varied from 0.04 to 0.12 μg/kg in barley and malt, 0.08-0.58 μg/kg in different hop samples, 0.04-0.12 μg/kg in brewers’ yeast and spent grains and 1.5-4.7 ng/l in beer. Limits of quantification varied from 0.13 to 0.39 μg/kg in barley and malt, 0.25-1.94 μg/kg in different hop samples, 0.13-0.39 μg/kg in brewers’ yeast and spent grains and 5.1-15.2 ng/l in beer. In 7 of 216 samples of brewing raw materials (3.2%), aflatoxins were found at trace concentrations to 1.2 μg/kg. In 6 of 117 (5.1%) beer samples, aflatoxins were detected at concentrations to 31.0 ng/l. Values in barley and malt did not exceed the maximum allowable limit set by the European Union.     

Aflatoxin M1 contamination in dairy products marketed in Iran during winter and summer

In the present study, 298 dairy product samples consisting of pasteurized milk (91 samples), yoghurt (68 samples), white cheese (72 samples), butter (31 samples) and ice cream (36 samples) collected from popular markets in four large Iranian cities were examined for aflatoxin M₁ (AFM₁) by thin layer chromatography (TLC) technique. The toxin was detected in 66 (72.5%) pasteurized milk samples (mean: 0.052 μg/l; range: 0.013–0.250 μg/l), 45 (66.1%) yoghurt samples (mean: 0.032 μg/kg; range: 0.015–0.119 μg/kg), 59 (81.9%) white cheese samples (mean: 0.297 μg/kg; range: 0.030–1.200 μg/kg), 8 (25.8%) butter samples (mean: 0.005 μg/kg; range: 0.013–0.026 μg/kg) and 25 (69.4%) ice cream samples (mean: 0.041 μg/kg; range: 0.015–0.132 μg/kg). The concentration of AFM₁ in 36.2%, 20.6%, 30.5%, 9.6% and 27.7% of pasteurized milk, yoghurt, white cheese, butter and ice cream samples, respectively, were higher than Iranian national standard limits. Levels of AFM₁ in samples of pasteurized milk, yoghurt, butter and ice cream collected in winter were significantly higher (P < 0.05) than those collected in summer. In the case of white cheese, level of AFM₁ was higher in winter than in summer, but the difference was not statistically significant (P > 0.05). The results indicated that the contamination of the dairy products in such a level could be a serious public health problem at the moment.     

Aflatoxin M1 contamination in white and Lighvan cheese marketed in Rafsanjan,Iran

This study was a screening survey to determine the occurrence of aflatoxin M₁ (AFM₁) in 82 cheese samples composed of white cheese (45 samples) and Lighvan cheese (37 samples) obtained from supermarkets and retail outlets in Rafsanjan city of Iran. The competitive enzyme immunoassay method was used for determination of the toxin in the samples. Aflatoxin M₁ was detected in 39 (47.6%) samples, consisting of 29 (64.4%) white cheese (mean: 135 ng/kg; range: 93.3–309 ng/kg) and 10 (27%) Lighvan cheese samples (mean: 90.8 ng/kg; range: 70.5–203 ng/kg). According to Iranian national standard limit for AFM₁ in cheese (200 ng/kg), 9 samples (20%) of white cheese and 1 sample (2.70%) of Lighvan cheese had levels above the limit. It was concluded that the contamination of the samples with AFM₁ in such a level could be considered as a serious public health problem.     

A fast and simple LC-ESI-MS/MS method for detecting pyrrolizidine alkaloids in honey with full validation and measurement uncertainty

A fast and simple method was developed to determine pyrrolizidine alkaloids (PAs) in honey using liquid chromatography tandem mass spectrometry (LC- MS/MS) with electrospray ionization (ESI). An efficient extraction procedure was carried out by simply diluting with water, without the need of any additional clean-up steps. A full validation of the method was performed according to Commission Decision 2002/657/EC. The method was linear in the 050 μg kg⁻¹ range and presented satisfactory intra-day and inter-day precision with relative standard deviations of 1.45–10.2% and 1.60–1–0.2%, respectively. The measurement uncertainty, limit of detection (LOD) (0.1–1.0 μg kg⁻¹) and limit of quantification (LOQ) (0.2–1.5 μg kg⁻¹) were also calculated. The proposed method was applied to analyse eight PAs, namely, senecionine, senecionine-N-oxide, echimidine, intermedine, lycopsamine, retrorsine, monocrotaline and retrorsine-N-oxide, in 92 commercial honey samples from Brazil. At least three PAs were detected in 99.1% of the samples. PAs were not detectable (<LOD) in only one sample. Because PAs are natural toxins biosynthesized by plants, the importance of monitoring their concentration in honey is evident. For this purpose, a simple, low-cost extraction procedure was performed, and a high-throughput method was developed.     

Aflatoxin M1 in raw milk in Croatia

In this study the levels of aflatoxin M₁ (AFM₁) of 61 milk samples delivered from small milking farms were determined in January, February, March and April (winter–spring season), and June, July and September (summer–autumn season) of 2009. The AFM₁ concentration was determined by competitive enzyme-immunoassay method. The maximum mean concentrations of AFM₁ recorded in winter–spring season were in the range of 35.8–58.6 ng/l and in summer–autumn season in the range of 11.6–14.9 ng/l. The AFM₁ levels determined in January, February, March and April were significantly higher in accordance with concentration of AFM₁ in June, July and September (P < 0.05 to P < 0.0001, respectively). Also, there was significant difference (P < 0.0001) between the mean concentrations of AFM₁ in samples taken all together in winter–spring and summer–autumn season. Only in one sample delivered in February the level of AFM₁ was higher than the maximum tolerance limit (50 ng/l). Therefore, it was concluded that in 98.4% of milk samples in Croatia the levels of AFM₁ were below maximum tolerance level accepted by the European Union.     

Aflatoxins and fumonisins in rice and maize staple cereals in Northern Vietnam and dietary exposure in different ethnic groups

Mycotoxins in food are increasingly a food safety hazard concern in particular in developing countries. This study was performed to determine the occurrence and determinants of aflatoxin and fumonisin contamination in rice and maize and to assess health risks through dietary intake exposure among ethnic minority groups in northern Vietnam. A total of 111 rice and 102 maize samples, were tested for occurrence of fungi and mycotoxins, i.e. aflatoxins (AF’s) and fuminisin B (FB). Results showed that 107 (96.4%) rice and 84 (82.4%) maize samples were contaminated by fungi. Aspergillus flavus was found in 68 (61.3%) rice and 30 (29.4%) maize samples, Aspergilus parasiticus in 40 (36.0%) rice and 27 (26.7%) maize samples. AF’s - were detected in 27 rice (24.3%) and 27 maize samples (26.4%) at minimum and maximum levels in rice of 2.06 and 77.8 ng/g and 20.5 and 110 ng/g in maize, respectively. Nine (8.1%) rice and 24 (23.5%) maize samples contained FB at ranges of 2.3–624 ng/g in rice and 5.6–89.8 ng/g in maize. Data collected through interviews and observations in households showed that type of crop, storage duration and presence of fungi, particularly mycotoxigenic fungi were important risk factors for AF’s and FB contamination. Based on daily food consumption data, the estimated average exposure dose of aflatoxin B₁(AFB₁) from rice was 21.7 ng/kg bw/day for adults and 33.7 ng/kg bw/day for children. For FB, the rice based average exposure amounted to 536 ng/kg bw/day for adults and 1019 ng/kg bw/day for children. The calculated excess risk of liver cancer incidence by ingestion of cereals containing AFB₁ was 1.5 per 100,000 adults and 2.3 per 100,000 children per year. The average intake of FB was calculated to be lower than the tolerable diet intake (TDI). Our findings highlight that rice and maize are contaminated with mycotoxins at levels representing actual health hazards for the ethnic minority groups consuming these stable cereals. Proper drying and storage conditions in households are likely to reduce the mycotoxin contamination.     

Analysis of aflatoxin M1 and M2 in commercial dairy products using high-performance liquid chromatography with a fluorescence detector

Aflatoxin M₁ (AFM₁) and M₂ (AFM₂) in commercial dairy products were analyzed by high-performance liquid chromatography (HPLC) with a fluorescence detector (FLD). To ensure an accurate analysis, two derivatization methods, bromination and aflatoxin–trifluoroacetic acid derivatization (ATD), were compared. The limits of detection (LODs) of the bromination method were 124.42–151.73 ng/kg, and the recovery rates were between 64 and 102%. The detection rates and concentration levels of AFM₁ were 6–74% and 14.48–270.94 ng/kg, respectively. AFM₁ was detected in 74% of milk powder samples and 36% of ice cream samples. The mean values of AFM₁ in milk powder and ice cream samples were 270.94 and 33.16 ng/kg, respectively. In the case of AFM₂, the detection rates were 2–10%, and the concentration levels were 20.62–55.67 ng/kg in milk and milk powder. Among milk and milk powder samples, ultra heat-treated (UHT) milk had lower AFM₁ contamination levels than pasteurized milk.     

Development of a new broad-specific monoclonal antibody with uniform affinity for aflatoxins and magnetic beads-based enzymatic immunoassay

To reduce the incidence of false-positive and false-negative results caused by high or low cross-reactivity (CR%) values of the antibodies for total aflatoxins (AFs, AFB₁+AFB₂+AFG₁+AFG₂) detection, a new broad-specific monoclonal antibody (MAb) with uniform affinity, named 5H3, was developed. Moreover, magnetic beads (MBs) replaced microplates as immobile phase to improve the sensitivity of the enzymatic immunoassay. Then, a direct competitive enzyme-linked immunosorbent assay (ELISA) based on MBs (MBs-dcELISA) that could simultaneously detect the total AFs with similar sensitivity was developed. Following optimization of conditions, the half maximal inhibitory concentrations (IC₅₀) of the MBs-dcELISA in buffer were 0.05 ng/mL for AFB₁, 0.04 ng/mL for AFB₂, 0.05 ng/mL for AFG₁, 0.06 ng/mL for AFG₂. The corresponding CR% values were 100%, 125%, 100% and 83.3%, respectively. The limit of detection (LOD) of the MBs-dcELISA for the total AFs was 0.21 ng/g with a working range from 0.22 ng/g to 19.8 ng/g, and the recoveries for the total AFs ranged from 74.5% to 96.5% with coefficients of variation (CV) under 12.1% in spiked maize samples. In addition, the MBs-dcELISA was more sensitive than the conventional dcELISA. Finally, the MBs-dcELISA was applied to screen 9 naturally contaminated maize samples and 6 spiked samples and the results indicated a good agreement with that obtain by HPLC-MS/MS method.     

Occurrence and factors associated with the presence of aflatoxin M1 in breast milk samples of nursing mothers in central Mexico

Aflatoxin M₁ (AFM₁) is the main mycotoxin frequently found in milk and dairy products. Exposure of infants to AFM₁ is of great health public concern because of its toxic and carcinogenic properties. The aim of this study was to determine the occurrence, levels and factors associated with the presence of aflatoxin M₁ in breast milk samples of nursing mothers in central Mexico. A total of 112 samples were collected and analyzed by a competitive-ELISA assay during January–August 2014. A Semi-Quantitative Food Frequency Questionnaire was used to determine weekly intake of food groups. Results showed that 89% of breast milk samples contained AFM₁ in a range of 3.01–34.24 ng/L. AFM₁ mean level was significantly higher (P < 0.05) in winter (12.78 ng/L) and spring (12.09 ng/L) than summer (7.91 ng/L). It was also detected that 7% of samples exceeded the European Community regulation (25 ng/L) for milk infant formula. The presence of aflatoxin M₁ was significantly associated (P < 0.05) to consumption of egg, cola drink and sunflower oil. The high occurrence and noticeable levels of AFM₁ detected, as well as the mean AFM₁ estimated daily intake (2.35 ng/kg b.w./day) suggested, for the first time, that breast-fed infants in the central region of Mexico, may be exposed to significant levels of this toxin through mother's breast milk.     

Deoxynivalenol and zearalenone occurence in beers analysed by an enzyme-linked immunosorbent assay method

The occurrence of deoxynivalenol and zearalenone in samples of 91 beers commercialised in Poland was the topic of investigation. Most of beers were produced by domestic companies. The analysis was conducted using the enzyme-linked immunosorbent assay method (ELISA). Deoxynivalenol has been found in 100% and zearalenone in 11% of tested beer samples, with ranges of 6–70.2 μg/L and 0–0.546 μg/L, respectively. The mean levels of 20.66 μg/L for deoxynivalenol and 0.044 μg/L for zearalenone contribute on average of 8.6% and 0.04% of the estimated tolerable daily intake of both mycotoxins, considering an average daily intake of 0.25 l of beer per capita in Poland. The concentration of deoxynivalenol was found to be slightly higher in top-fermented beers. The deoxynivalenol content was also higher in dark-coloured beers both in the top-fermented and bottom-fermented beer samples. The regression analysis showed very little correlation between deoxynivalenol content and alcohol percentages by volume.     

Seasonal prevalence level of aflatoxin M1 and its estimated daily intake in Pakistan

Aflatoxin M₁ level was measured in 520 milk samples during autumn, winter, spring and summer seasons of 2013–14 in five districts of Southern Punjab-Pakistan. Analyses were performed by using enzyme linked immuno sorbent assay (ELISA) method. Aflatoxin M₁ was found positive in 93% milk samples in the range of 0.001–0.26 μg/l while 53% samples were found to exceed the European Union maximum Limit for aflatoxins M₁ i.e. 0.05 μg/l. The seasonal prevalence level of AFM₁ was found in the order of winter > spring > autumn > summer. Comparing the aflatoxin M₁ level during different day times, morning milk was found 37–50% more contaminated than evening milk. The estimated daily intake (EDI) of aflatoxins M₁ during different seasons of year for various age groups was found in the range of 0.22–5.45 ng/kg/day. Infants were found in the highest risk group while adults were in the lowest. The results of the study indicate that people of Pakistan are at high risk of health issues related with aflatoxins M₁.     

Microbial quality and safety of fresh and dried Rastrineobola argentea from Lake Victoria,Tanzania

Rastrineobola argentea (silver cyprinid/sardines) is an important commercial fish species found in Lake Victoria. It is an important protein source for consumers in several African countries including Tanzania. A cross-sectional study was conducted using standard methods to assess the bacteriological quality of fresh and dried sardines from Lake Victoria. Sardine samples were randomly collected from main landing sites and retail markets in the city of Mwanza. Total viable counts (TVC) in fresh sardines were in the range of 5.18–7.90 log₁₀ cfu/g while those dried on racks contained 3.13–4.85 log₁₀ cfu/g which were 0.75% of those dried on sand with 4.80–7.13 log₁₀ cfu/g (p < 0.001, 95% CL: 0.40%–1.42%). Thus, rack dried sardines had mean TVC below the national acceptable food standard of 5 log₁₀ cfu/g. Faecal contamination with E. coli in fresh sardines ranged from 2.38 to 5.38 log₁₀ mpn/g and those dried on sand contained 1.18–3.32 log₁₀ mpn/g, however, sardines dried on racks, did not contain any E. coli. Similar findings were found in the two types of dried sardines from the retail markets. Prevalence of Salmonella spp. in fresh R. argentea was 25% (n = 40), sand dried sardines at landing sites contained 30% (n = 20) and those from the markets contained 15% (n = 20) Salmonella spp. Salmonella spp. were not detected in sardines dried on racks. To conclude, sun drying of sardines on racks is an effective drying method providing a safe product for human consumption.     

Concentration of ochratoxin A in breakfast cereals and snacks consumed in the United States

A total of 144 breakfast cereal and snack samples collected from six areas in the United States (U.S.) were surveyed for the presence of ochratoxin A (OTA). All samples are the processed products including mainly corn, oat, wheat, and rice. The analytical methods in this study were immunoaffinity columns (IAC) and high performance liquid chromatography (HPLC) with fluorescence detection (FLD). The method provided recoveries of OTA from all sample matrices in the range of 95–100%. The limits of detection and limits of quantification for OTA were 0.032 and 0.10 ng/g for corn, wheat, and rice based samples; 0.038 and 0.12 ng/g for oat based samples, respectively. Analytical results showed that 75 samples (52%) were contaminated with OTA in the range of 0.10 and 7.43 ng/g. Among the OTA contaminated samples, 40% were labeled as organic and 60% were conventional with mean concentrations of 1.21 and 1.07 ng/g, respectively. There were ten contaminated samples, all from oat based products, exceeding the maximum limits for OTA by European Commission Regulation (3 ng/g) in cereal based products.     

The seasonal variation of aflatoxin M1 in milk and dairy products and assessment of dietary intake in Punjab,Pakistan

Total 372 samples (169 sample from summer and 203 samples from winter) of milk and dairy products were collected from major cities of Punjab, Pakistan, during 2014–2015. The aflatoxin M₁ (AFM₁) levels were analyzed using HPLC, equipped with floresceⁿce detector. The results have showed that AFM₁ was detected in 77 (45.5%) samples of milk and dairy products from summer at the range of LOD to 229.6 ng/L, and 114 (56.1%) samples from winter at a range of LOD to 345.8 ng/L. The highest mean of AFM₁ i.e. 94.9 ± 5.4 ng/L from summer and 129.6 ± 8.4 ng/L from winter was detected in raw milk samples. The results have shown that 37.5% of milk, 32% of UHT milk, 12.5% of powdered milk, 20% of flavored milk, 20% of yogurt and 16% of flavored milk samples from summer were found exceeded the recommended levels of AFM₁ i.e 50 ng/L (European Union permissible limit), as compared to 38.1%, 37.1%, 15.6%, 21.4%, 27.7% and 40% samples of milk, UHT milk, powdered milk, flavored milk, yogurt and flavored yogurt from winter, respectively. The mean level of AFM₁ in samples of milk, UHT milk and powdered milk samples from winter season has significantly (p˂ 0.05) higher as compared to the mean levels in samples from summer season. The dietary exposures of AFM₁ in milk and dairy products were calculated in five different age groups and the highest level of 3.42 and 3.33 ng/L/day in summer and 4.7 and 4.6 ng/L/day in winter were found in 1–5 years of male and female infants, respectively. The results of present study have shown significant levels of AFM₁ in milk and dairy products from Punjab, Pakistan and could pose considerable thereat to the health of local population.     

Fumonisin occurrence in naturally contaminated wheat grain harvested in Argentina

A survey was carried out to determine fumonisin contamination in 135 common and 40 durum wheat samples collected during 2011 harvest season (non-FHB epidemic year) in the main wheat production area of Argentina using LC–MS/MS. A 93% of total samples showed fumonisin contamination, with levels ranging from 0.16 to 680.44 ng/g in common and from 0.15 to 1304.39 ng/g in durum wheat samples, respectively. FB₁ was the fumonisin most frequently found during the evaluated year. Twenty five wheat samples (15 common and 10 durum) were selected for a deoxynivalenol (DON) analysis among all the samples analyzed for fumonisin content using different contamination levels as selection criteria. DON contamination was present in 24 out of 25 wheat samples, the levels ranging from 50.60 to 28650 ng/g. Nine out of 25 wheat samples reached values higher than 1000 ng/g. However there was no correlation between fumonisin and DON contamination. This is the first report of natural fumonisin presence in common wheat grains in Argentina, as well as of DON co-occurrence in both types of wheat.     

Occurrence of aflatoxin contamination in maize throughout the supply chain in the Democratic Republic of Congo

Aflatoxin occurs ubiquitously in maize and is both an economic and a public health concern due to its carcinogenic effects. Nevertheless, in developing countries such as the Democratic Republic of Congo, there is still a dearth of information regarding its natural occurrence, exposure to both humans and animals and strategies for controlling its proliferation or contamination of food crops such as maize. The present study comparatively assessed the aflatoxin occurrence in maize samples collected in the DRC throughout the food supply chain. The analytical method used during this experiment was found to be accurate with a recovery ranging between 70.65 and 98.20%, and also precise (RSD<15%) except for AFG₁, which showed an RSD of 18.05%. Moreover, the limits of detection (LOD) and quantification (LOQ) for aflatoxin ranged from 0.31 to 0.69 μg/kg and from 1 to 2 μg/kg, respectively. The results also revealed that in the pre-harvest period, 32% of maize samples (out of a total of 50) were positive, with aflatoxins at a range of 1.5–51.23 μg/kg for AFB1 and 3.1–103.89 μg/kg for total aflatoxin. As the supply chain progresses, the contamination of maize samples also increases, with 100% of the collected maize samples found to contain aflatoxins at 300 times higher than the maximum limit of 10 μg/kg for total aflatoxin as set by the WHO. The aflatoxin content of maize samples was found to increase drastically at up to 500 times between the city store and the distribution system at market level. This was confirmed with a statistical analysis showing a significant difference (p < 0.01) between city store/market samples and pre-harvest, harvest, farm store and after-transportation samples.     

A UPLC-MS/MS for simultaneous determination of aflatoxins, ochratoxin A, zearalenone, DON, fumonisins, T-2 toxin and HT-2 toxin, in cereals

An ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method is described for simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁ and AFG₂), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB₁ and FB₂), T-2 and HT-2 toxins in cereals. Mycotoxins were separated by reverse phase liquid chromatography (RP-LC) and detected by tandem mass spectrometry using an electro spray-ionization interface (ESI) in both positive- and negative- ion modes. The mean recoveries of mycotoxins from spiked cereals ranged from 83.5% to 107.3%, whereas the limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.01 to 25 ng/g and 0.02-40 ng/g, respectively. The multi-mycotoxin method developed in this work was applied for the simultaneous determination of mycotoxins in 80 cereal samples collected from Malaysian markets. A total of 60 cereal samples (75%) were contaminated with at least one of these mycotoxins at levels greater than the LOD. Only one maize sample and two rice samples were contaminated at levels exceeding the European regulatory limits for aflatoxins and OTA (4 and 5 ng/g, respectively). The rates of the occurrence of mycotoxins in the commercial cereal samples were 50, 30, 19, 30, 16, 14, 14 and 12% for the aflatoxins (the total amount of AFB₁, AFB₂, AFG₁ and AFG₂), OTA, ZEA, DON, FB₁, FB₂, T-2 and HT-2 toxins, respectively. The results demonstrated that the procedure was suitable for the simultaneous determination of these mycotoxins in cereals and could be performed for their routine analysis in mycotoxin laboratories.