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1.
A validated high-performance liquid chromatography (HPLC) method with fluorescence detection for the quantitative analysis of ochratoxin A (OTA) in cocoa beans is described. OTA was extracted with methanol-3% sodium hydrogen carbonate solution and then purified with immunoaffinity columns before its analysis by HPLC. The validation of the analytical method was based on the following criteria: selectivity, linearity, limit of detection and quantification, precision (within- and between-day variability) and recovery, robustness and uncertainty. Detection and quantification limits were 0.04 and 0.1 μg kg-1, respectively. Recovery was 88.9% (relative standard deviation = 4.0%). This method was successfully applied to the measurement of 46 cocoa bean samples of different origins. A total of 63% of cocoa bean samples was contaminated with a level greater than the limit of detection. The means and medians obtained for cocoa bean were 1.71 and 1.12 μg kg-1, respectively. Surveillance controls should be set up in both crops and factories involved in transformation processes to avoid this mycotoxin in final products.  相似文献   

2.
Ochratoxin A (OTA) is a mycotoxin mainly produced by mould species of the genera Aspergillus and Penicillium, which grow on a variety of agricultural products. OTA-contaminated foodstuffs pose a major health hazard to consumers, including human and animal. In Côte d’Ivoire, numerous studies are being carried out to find the best way of preventing OTA contamination of cocoa raw material. The objectives of this investigation were to assess the impact of industrial treatment on OTA content in cocoa-derived products. Samples of cocoa pods were prepared under specific conditions promoting fungal proliferation on cocoa beans before processing. The beans underwent the usual industrial treatments – roasting, shelling, crushing, pressing and additive addition – and samples were taken at each stage. OTA was extracted with a methanol/3% sodium hydrogen carbonate solution and purified using an immunoaffinity column prior to HPLC analysis with fluorescence detection. OTA was detected in artificially contaminated cocoa beans at levels ranging from 3.4 to 44.7 µg kg?1 with a mean value of 22.9 ± 3.6 µg kg?1. OTA was mainly concentrated in the shell (93%). Roasting, shelling and additive addition significantly decreased levels of OTA by 24–40, 76 and 52%, respectively, with an overall reduction of ~91%. These results indicate that industrial processing of cocoa has a real impact on the reduction of OTA in final cocoa products.  相似文献   

3.
Cocoa beans are the principal raw material for chocolate manufacture. Moulds have an important place in the change in the quality of cocoa beans due to their role in the production of free fatty acids and mycotoxins, namely ochratoxin A (OTA). This study investigated the impact of the key post-harvest treatments, namely the fermentation and drying methods on OTA contamination of raw cocoa beans. Analytical methods for OTA detection were based on solid–liquid extraction, clean-up using an immunoaffinity column, and identification by reversed-phase HPLC with fluorescence detection. Of a total of 104 randomly selected cocoa samples analysed, 32% had OTA contents above 2 µg kg–1. Cocoa sourced from pods in a bad state of health had a maximum OTA content of 39.2 µg kg1, while that obtained from healthy pods recorded 11.2 µg kg–1. The production of OTA in cocoa beans increased according to the pod-opening delay and reached 39.2 µg kg–1 after an opening delay of 7 days after harvest, while 6.1 and 11.2 µg kg–1 were observed when pods were opened after 0 and 4 days. OTA production also seemed to depend considerably to the cocoa fermentation materials. When using plastic boxes for bean fermentation, the OTA production was enhanced and reached an average OTA content of about 4.9 µg kg1, while the raw cocoa treated in banana leaves and wooden boxes recorded 1.6 and 2.2 µg kg–1 on average respectively. In parallel, the OTA production was not really influenced by either the mixing or the duration of the fermentation or the drying materials.  相似文献   

4.
In the present study, the occurrence of aflatoxins (AFs) and ochratoxin A (OTA) was evaluated in 123 samples of cocoa beans produced in five Brazilian states. The presence of these mycotoxins was determined by high-performance liquid chromatography with fluorescence detection (HPLC-FLD) after immunoaffinity column clean-up. The mean level of total AFs in cocoa beans samples was 5.7 μg.kg?1. Four (3.3%) samples exceeded the maximum limit of 10 μg.kg?1 established by the Brazilian legislation for total AFs. The mean level of OTA contamination was 1.2 μg.kg?1, and none of the samples exceeded the maximum limit established by the Brazilian legislation. The co-occurrence of AFs and OTA was observed in 4.9% of the samples. The results of the present study demonstrated that, in relation to the levels of AFs and OTA established by the Brazilian legislation, most samples of cocoa beans analyzed are safe for consumption. This is the first report on the occurrence and levels of AFs and OTA in cocoa beans from the five main Brazilian states producing cocoa. The data in this study provide important information for farmers, traders, industry, consumers and law enforcement agencies.  相似文献   

5.
Cocoa is an important ingredient for the chocolate industry and for many food products. However, it is prone to contamination by ochratoxin A (OTA), which is highly toxic and potentially carcinogenic to humans. In this work, four different extraction methods were tested and compared based on their recoveries. The best protocol was established which involves an organic solvent-free extraction method for the detection of OTA in cocoa beans using 1% sodium hydrogen carbonate (NaHCO3) in water within 30 min. The extraction method is rapid (as compared with existing methods), simple, reliable and practical to perform without complex experimental set-ups. The cocoa samples were freshly extracted and cleaned-up using immunoaffinity column (IAC) for HPLC analysis using a fluorescence detector. Under the optimised condition, the limit of detection (LOD) and limit of quantification (LOQ) for OTA were 0.62 and 1.25 ng ml–1 respectively in standard solutions. The method could successfully quantify OTA in naturally contaminated samples. Moreover, good recoveries of OTA were obtained up to 86.5% in artificially spiked cocoa samples, with a maximum relative standard deviation (RSD) of 2.7%. The proposed extraction method could determine OTA at the level 1.5 µg kg1, which surpassed the standards set by the European Union for cocoa (2 µg kg–1). In addition, an efficiency comparison of IAC and molecular imprinted polymer (MIP) column was also performed and evaluated.  相似文献   

6.
In October and November 2004, 91 spice samples (70 ground red pepper, six black pepper, five white pepper, five spice mix and five chilli samples), the majority of which originated from commercial outlets, were analysed for aflatoxins B1, B2, G1 and G2 (AFB1, AFB2, AFG1, AFG2) and ochratoxin A (OTA) content by high-performance liquid chromatography (HPLC) after immunoaffinity column clean-up. Eighteen of the 70 ground red pepper samples contained AFB1, seven of them in a concentration exceeding the 'maximum level' of 5 µg kg-1 (range 6.1-15.7 µg kg-1). Of the other spices assayed, the AFB1 contamination of one chilli sample exceeded 5 µg kg-1 (8.1 µg kg-1). Thirty-two of the 70 ground red pepper samples contained OTA, eight of them in a concentration exceeding the 10 µg kg-1 'maximum level' (range 10.6-66.2 µg kg-1). One chilli sample was contaminated with OTA at 2.1 µg kg-1. The AFB1 and OTA contamination of ground red pepper exceeding the 'maximum level' (5 and 10 µg kg-1, respectively) was obviously the consequence of mixing imported ground red pepper batches heavily contaminated with AFB1 and OTA with red pepper produced in Hungary. This case calls attention to the importance of consistently screening imported batches of ground red pepper for aflatoxin and ochratoxin A content and strictly prohibiting the use of batches containing mycotoxin concentrations exceeding the maximum permitted level.  相似文献   

7.
Brazil is the sixth largest producer of cocoa beans in the world, after Côte d’Ivoire, Ghana, Indonesia, Nigeria and Cameroon. The southern region of Bahia stands out as the country’s largest producer, accounting for approximately 60% of production. Due to damage caused by infestation of the cocoa crop with the fungus Moniliophthora perniciosa, which causes ‘witch’s broom disease’, research in cocoa beans has led to the cloning of species that are resistant to the disease; however, there is little information about the development of other fungal genera in these clones, such as Aspergillus, which do not represent a phytopathogenicity problem but can grow during the pre-processing of cocoa beans and produce mycotoxins. Thus, the aim of this work was to determine the presence of aflatoxin (AF) and ochratoxin A (OTA) in cocoa clones developed in Brazil. Aflatoxin and ochratoxin A contamination were determined in 130 samples from 13 cocoa clones grown in the south of Bahia by ultra-performance liquid chromatography with a fluorescence detector. The method was evaluated for limit of detection (LOD) (0.05–0.90 μg kg?1), limit of quantification (0.10–2.50 μg kg?1) and recovery (RSD) (89.40–95.80%) for AFB1, AFB2, AFG1, AFG2 and OTA. Aflatoxin contamination was detected in 38% of the samples in the range of ?1, with AFB1 in 25% of the total samples, whereas ochratoxin A was positive in 18% of the samples in the range of ?1.  相似文献   

8.
A simple analytical method for ochratoxin A (OTA) determination in grapes is described, using aqueous methanolic extraction, an immunoaffinity column clean-up step and high-performance liquid chromatography with fluorescence detection. Mean recovery was 94% (RSD = 4.0%) with a detection limit of 0.4 ng g-1 and quantification limit of 1.20 ng g-1. Repeatability (r) and reproducibility (R) were 1.17 and 1.34, respectively. OTA determinations were applied to 50 grape samples (23 different varieties) originating from representative regions of Greece. Results showed the presence of OTA in 86% of samples tested (n = 50). Traces were found in 56% of samples but OTA was not detectable in 14% of samples. Traces were also found in 4% of red, organically grown samples. The most contaminated were three samples of red grapes, two from Central Greece (2.69 and 1.41 ng g-1), both table and wine-making grapes. The third sample (1.46 ng g-1), originating from the island of Samos, was used only in wine-making. Mean (1.06 ng g-1) and median (0.76 ng g-1) OTA concentrations in red grapes were slightly higher compared to the mean (0.82 ng g-1) and median (0.65 ng g-1) concentrations in white grape samples. The study shows that the potential risk for a person of 60 kg ranged from 0.9 to 9 ng kg-1 bw day-1 and is dependent on the quantity of grapes consumed daily.  相似文献   

9.
A method of screening sultanas for ochratoxin A (OTA) contamination, using mid-infrared spectroscopy/Golden Gate single-reflection ATR (attenuated total reflection), is described. The main spectral characteristics of sultanas from different sources were identified in a preliminary acquisition and spectral analysis study. Principal component analysis (PCA) showed that samples of various origins had different spectral characteristics, especially in water content and the fingerprint region. A lack of reproducibility was observed in the spectra acquired on different days. However, spectral repeatability was greatly improved when water activity of the sample was set at 0.62. A calibration curve of OTA was constructed in the range 10-40 µg OTA kg-1. Samples with OTA levels higher than 20 µg kg-1 were separated from samples contaminated with a lower concentration (10 µg OTA kg-1) and from uncontaminated samples. The reported methodology is a reliable and simple technique for screening dried vine fruit for OTA.  相似文献   

10.
An improved specific analytical method for ochratoxin A (OTA) determination in olive oil is described, using a methanolic-aqueous extraction, an immunoaffinity column clean up step and high-pressure liquid chromatography with fluorescence detection. The mean recovery was found at 108% (relative standard deviation, RSD = 4.7%) and the detection limit (DL) was estimated at 4.6 ng kg-1. Along with OTA, aflatoxin B1 (AFB1) was determined using the same extract. The recovery factor was 84.8% (RSD = 17.8%) and the DL was 56 ng kg-1 olive oil. Both determinations were applied in 50 samples of olive oil originated from representative regions of Greece. Results revealed the presence of OTA in 88% of samples tested (n = 44, mean 267 ng kg-1). Among them, 10 were contaminated with more than 500 ng kg-1 (median 568 ng kg-1), 10 with 200-500 ng kg-1 (median 260 ng kg-1), 15 with 100-200 ng kg-1 (median 140 ng kg-1), nine with DL-100 (median 60 ng kg-1) and in six samples, OTA was not detectable. Interestingly, most contaminated samples were from Southern Greece. Results of AFB1 determination showed the presence of aflatoxin B1 (60 ng kg-1) in only one olive oil sample also from Southern Greece. The levels of OTA found in Greek olive oil were relatively low as compared with other commodities such as cereals or wine reported in the literature.  相似文献   

11.
A study of the effect of coffee processing in the ochratoxin A (OTA) level has been carried out from the green beans to the drinking form. The analysis of OTA has been carried out by an in-house validated HPLC method with fluorescence detection. The limits of detection were 0.04 µg/kg for green and roasted coffee, and 0.01 µg/L for coffee brew. Thirty-six green coffee samples of different origin (Colombia, Costa Rica, Brazil, Vietnam, India and Uganda) were analysed. The highest concentrations of OTA were found in Vietnamese samples - Robusta species treated by dry processing - (range 0.64-8.05 µg/kg), that also showed the highest percentage of defective beans (7.6%). These contaminated samples were roasted in a process that controlled loss of weight and color, as in the industry. A mean reduction of 66.5% was obtained, but the reduction seems to be heterogeneous. Coffee brew was prepared by the three brewing processes more utilized in Europe: moka, auto-drip and espresso. A reduction of the OTA level has been attained, being greater when using a espresso coffee maker (49.8%) than when using auto-drip (14.5%) or moka brewing (32.1%). Therefore, the method of coffee brew preparation plays a key role in the final OTA human exposure.  相似文献   

12.
In 2006 and 2007, 32 Thai dried coffee bean samples (Coffea arabica) from two growing sites of Chiang Mai Province, and 32 Thai dried coffee bean samples (Coffea canephora var. robusta) from two growing sites of Chumphon Province, Thailand, were collected and assessed for the distribution of fungi with the potential to produce ochratoxin A (OTA). The overall percentage of fungal contamination in coffee was 98% and reduced to 60% after surface disinfection. There were remarkable ecological differences in the composition of ochratoxigenic species present in these two regions. Arabica coffee bean samples from the North had an average of 78% incidence of colonization with Aspergillus of section Circumdati with Aspergillus westerdijkiae and A. melleus as the predominant species. Aspergillus spp. of section Nigri were found in 75% of the samples whereas A. ochraceus was not detected. Robusta coffee beans from the South were 98-100% contaminated with predominantly A. carbonarius and A. niger. A. westerdijkiae was only found in one sample. The diversity of the fungal population was probably correlated with the geographical origin of the coffee, coffee cultivar, and processing method. Representative isolates of section Circumdati (52) and Nigri (82) were examined for their OTA production using HPLC with fluorescence detection. Aspergillus westerdijkiae (42 isolates out of 42), A. steynii (13/13), and A. carbonarius (35/35) in general produced large amounts of OTA, while one isolate of A. sclerotiorum produced intermediate amounts of OTA. 13% of the A. niger isolates produced OTA in intermediate amounts. OTA levels in coffee bean samples were analyzed using the Ridascreen OTA ELISA kits. Of the 64 coffee bean samples analyzed, 98% were contaminated with OTA in levels of <0.6-5.5 microg/kg (Arabica) and 1-27 microg/kg (Robusta). Presence of OTA in representative coffee samples was also confirmed by LC-MS/MS after ion-exchange purification.  相似文献   

13.
Ochratoxin A (OTA), ochratoxin B (OTB) and citrinin (CIT) in commercial foods were simultaneously determined and confirmed with high-performance liquid chromatography (HPLC) and liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). The samples examined were made up of cereal, fruit, coffee, and cacao products. The limits of quantification (S/N> or =10) of OTA, OTB and CIT were 0.1 microg/kg or less. Aflatoxins (AF), deoxynivalenol (DON) and fumonisins were also surveyed. Of 157 samples examined, 44 were contaminated with OTA at levels of 0.11 to 4.0 microg/kg. At least 2 positive samples were labeled as domestics. In most positive samples, the OTA level was low, less than 1 microg/kg. The highest incidence of OTA was observed in cacao powder (10/12), followed by instant coffee (5/7), cocoa (5/8) and raisin (6/13). OTB was found in fruit and cacao products containing relatively high levels of OTA. Co-occurrence of OTA, CIT and DON was found in cereal products, and co-occurrence of OTA and AF was found in cacao products. Approximately 30% of naturally contaminated OTA in roasted coffee bean moved into the extract solution when brewed with paper filter.  相似文献   

14.
The results of surveillance for ochratoxin A (OTA) in 1885 samples of sultanas taken during five crop years between 1999 and 2003 are reported. The analytical method was based on extraction with methanol + sodium bicarbonate and clean-up by immunoaffinity column chromatography followed by high-performance liquid chromatography with fluorescence detection. The limit of detection for OTA was 0.3 µg kg-1. The results show that 9.3% of the samples contained no detectable levels of OTA, whereas 0.6% had concentrations exceeding 10 µg kg-1; the remaining 90.3% had levels within the range 0.3-10 µg kg-1. The overall mean OTA concentration in the total number of 1885 samples taken was 1.36 ± 2.91 µg kg-1; the overall median was calculated as 0.90 µg kg-1.  相似文献   

15.
A survey for the presence of ochratoxin A (OTA) was undertaken from 2001 to 2005 in 188 samples of sweet wines produced in Spain and in 102 samples originating from other countries: France (n = 49), Austria (9), Chile (9), Portugal (9), Greece (6), Italy (5), Germany (3), Hungary (2), Slovenia (2), Switzerland (2), Canada (1), Japan (1), New Zealand (1), Ukraine (1), South Africa (1) and the USA (1). The analytical method was based on immunoaffinity chromatography clean-up and high-performance liquid chromatography (HPLC) with fluorescence detection. The limit of detection (defined as a signal-noise ratio = 3) was estimated to be 0.01 µg l-1. The limit of quantification (0.02 µg l-1) was checked as being the lowest measurable concentration. OTA was detected in 281 out of 290 samples analysed (96.9% positive) at concentrations ranging from 0.01 to 4.63 µg l-1. The overall mean and median levels were estimated to be 0.50 and 0.14 µg l-1, respectively. In Spanish sweet wines OTA was found in 99% of the samples, with mean and median values of 0.65 and 0.19 µg l-1, respectively. The mean value obtained in this study for OTA in the Spanish sweet wines would result in an intake of about 37.5 and 3.2 ng day-1 of OTA for regular consumers and for the overall population, respectively. These figures represent a minor contribution to the provisional tolerable weekly intake (PTWI) or TWI established by the Joint Expert Committee on Food Additives (JECFA) and the European Food Safety Authority: 3.8 and 3.1% for regular consumers; and 0.4 and 0.3% for the whole adult population, respectively.  相似文献   

16.
Olive oil, the most important dietary fat source of the Mediterranean diet, can be contaminated by mycotoxins. An efficient analytical method for the simultaneous determination of aflatoxin B1 (AFB1) and ochratoxin A (OTA) in olive oil is reported. Thirty commercial samples of virgin olive oil, purchased in olive-press plants and supermarkets in southern Italy and North Africa, were analysed to verify the analytical procedure and monitor mycotoxin contamination. A simple, rapid and economic method was set up and tested for both the extractive step and the clean-up procedures for simultaneous AFB1 and OTA determination in olive oil. Data obtained showed that OTA was detected with high frequency (80%) in samples from both geographical areas (up to 17.0 ng g-1), while AFB1 was found from three of four samples from North Africa (up to 2.4 ng g-1). In addition, 'not labelled' oil samples proved to be more contaminated by OTA then 'labelled' samples (mean values of 2.47 and 0.66 ng g-1, respectively). These findings indicate that olive oil can be significantly contaminated by mycotoxins and confirm that a scrupulous application of European Regulation 1019/2002 (European Commission 2002), which prohibits the sale of non-labelled olive oil, is strongly recommended. Conventional qualitative parameters such as peroxide number, spectrophotometric evaluation and acid values were not correlated with mycotoxin occurrence.  相似文献   

17.
Mycotoxins are products of moulds that frequently contaminate maize. In this study the presence of mycotoxins fumonisin B1 (FB1), fumonisin B2 (FB2), zearalenone (ZEA) and ochratoxin A (OTA) was determined in 49 maize grain samples collected in autumn 2002. The most frequent finding was that of FB1(100%), followed by ZEA (84%) and OTA (39%), while FB2 was found only in three samples. The co-occurrence of two and three mycotoxins was found in 55 and 37% of samples, respectively. The concentrations (mean ± SD) of FB1, ZEA and OTA in positive samples were 459.8 ± 310.7, 3.84 ± 6.68 and 1.47 ± 0.38 µg kg-1, respectively, and the concentrations of FB2 in three positive samples were 68.4, 109.2 and 3084.0 µg kg-1. Although such low concentrations of mycotoxins are not a significant source of exposure in countries with a European diet, a few samples with extreme values indicate that thorough control is needed.  相似文献   

18.
In order to determine the levels of ochratoxin A (OTA) in cocoa and cocoa products available in Canada, a previously published analytical method, with minor modifications to the extraction and immunoaffinity clean-up and inclusion of an evaporation step, was initially used (Method I). To improve the low method recoveries (46-61%), 40% methanol was then included in the aqueous sodium bicarbonate extraction solvent (pH 7.8) (Method II). Clean-up was on an Ochratest? immunoaffinity column and OTA was determined by liquid chromatography (LC) with fluorescence detection. Recoveries of OTA from spiked cocoa powder (0.5 and 5 ng g(-1)) were 75-84%; while recoveries from chocolate were 93-94%. The optimized method was sensitive (limit of quantification (LOQ) = 0.07-0.08 ng g(-1)), accurate (recovery = 75-94%) and precise (coefficient of variation (CV) < 5%). It is applicable to cocoa and chocolate. Analysis of 32 samples of cocoa powder (16 alkalized and 16 natural) for OTA showed an incidence of 100%, with concentrations ranging from 0.25 to 7.8 ng g(-1); in six samples the OTA level exceeded 2 ng g(-1), the previously considered European Union limit for cocoa. The frequency of detection of OTA in 28 chocolate samples (21 dark or baking chocolate and seven milk chocolate) was also 100% with concentrations ranging from 0.05 to 1.4 ng g(-1); one sample had a level higher than the previously considered European Union limit for chocolate (1 ng g(-1)).  相似文献   

19.
Crop storage should be carried out under hygienic conditions to ensure safe products, but sometimes grain dust which has settled from previous storage may be left over and incorporated to the following stored grains. This paper describes the results obtained using a lab model developed in order to assess the impact of grain dust incorporation for its direct contribution as a contaminant but also as an inoculum in stored wheat. Settled grain dust (4 samples) released from Belgian grain storages were collected and analysed by HPLC for ergosterol, ochratoxin A (OTA) and citrinin (CIT) content. For OTA and for ergosterol, there was a high degree of variability in concentrations found in the dust samples (from 17.3-318 ng g-1 and from 39-823 µg g-1, respectively) whilst for CIT, the range was less significant (from 137-344 ng g-1). Incorporation of grain dust into wheat storage contributed to an increase in the concentrations of mycotoxins in the stored grain. Dust acts as a contaminant and as an inoculum. According to these two ways, patterns of mycotoxin generation vary with the nature of the mycotoxin, the mycotoxigenic potential of dust and the water activity of the wheat. OTA and CIT showed a very versatile image when considering the amounts of toxins produced under the selected experimental conditions. The development of a robust tool to forecast the mycotoxigenicity of dust was based on the determination of ergosterol content as a general marker of fungal biomass. Present results suggest that this predictive tool would only be valid for predicting the contamination level of CIT and OTA at reasonable moisture content (14-20%). The potential risk of having highly contaminated batches from stock to stock may thus occur and this paper discusses possible pathways leading to OTA and CIT contamination either under wet or dry storage conditions. We therefore, recommend taking precautionary measures not only by controlling and maintaining moisture at a reasonable level during storage of the raw materials but also by paying more attention to the cleaning of the stores before loading in the new harvests.  相似文献   

20.
The aim of this study was to determine the co-occurrence of aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEA) in paprika and chilli samples purchased in Spain, using HPLC with fluorescence detection. The occurrence of mycotoxin in 64 paprika samples was 59% for AFs, 98% for OTA and 39% for ZEA, whereas in the 35 chilli samples, the contamination was 40% for AFs, 100% for OTA and 46% for ZEA. None of the samples had AFs levels higher than the legally allowable limits. Regarding the co-occurrence of mycotoxins, 75% of paprika samples and 65% of chilli samples contained more than one mycotoxin. Chilli samples generally had lower concentrations of AFB1, AFB2, total AFs and OTA than had paprika samples. The high incidence of OTA contamination suggests that additional legislation may be required to for these kinds of spices.  相似文献   

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