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1.
Some mycotoxins are produced by several Fusarium species during cultivation and are found in wheat and maize grain. Since 2000, Syngenta has organised a large field survey. Agronomic and climatic data and grain samples have been collected for mycotoxin analysis in France and Belgium. The importance of the agroclimatic factors and their interactions on the mycotoxin levels in grain has been estimated. The climate around flowering stage is the major factor for deoxynivalenol (DON) in wheat. The main agronomic criteria are residue management and the variety sensitivity to this mycotoxin. For DON, zearalenone and fumonisins in maize, the climate from flowering stage until harvest is the major factor. Then, according to each mycotoxin, the main agronomic criteria are the harvest condition (date and grain moisture), the corn borer infestation and the variety sensitivity to these mycotoxins. Over the years, the database has been used to define models to predict the mycotoxin risk before harvesting. Grain purchasers enter the required agronomic data via the Syngenta Internet site and define their grain purchasing areas. They also define the flowering period for wheat and corn borer infestation for maize. After calculation which integrates climatic data, the purchasers receive reports with forecasts of mycotoxin levels. Prediction is based on different agro-climatic statistical models specifically configured according to the different regions of production in France and Belgium. This approach is called Qualimètre? and was the first service in France and Belgium to forecast the grain mycotoxin level for wheat in 2004 and maize in 2006.  相似文献   

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

3.
Deoxynivalenol-3-β-D-glucoside (D3G), a phase II plant metabolite of the mycotoxin deoxynivalenol (DON), occurs in naturally Fusarium-contaminated cereals. In order to investigate the frequency of occurrence as well as the relative and absolute concentrations of D3G in naturally infected cereals, 23 wheat samples originating from fields in Austria, Germany and Slovakia as well as 54 maize samples from Austrian fields were analysed for DON and D3G by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Both analytes were detected in all the 77 field samples. DON was found at levels from 42 to 4130 ng g?1 (977 ± 1000 ng g?1 on average). The D3G concentrations in all cereal samples were in the range 10–1070 ng g?1 (216 ± 253 ng g?1 on average), corresponding to about 5–46 mol% of their DON concentrations (15 ± 8 mol% on average).  相似文献   

4.
A total of 286 wheat samples for human consumption collected during 1997–2003 from four wheat-producing localities of south-western Uruguay were screened for deoxynivalenol (DON). Quantification was carried on by an immunochemical method using immunoaffinity columns and fluorimetric detection. The incidence of DON was high during the whole survey (58.5–100%), except in 1998 and 1999 in which no contamination occurred. During 2001 and 2002, 100% of samples contained detectable levels of DON, being the mean DON contents 6593 and 5880 µg kg?1, respectively. The annual maximum levels ranged from 8800 to 11,400 µg kg?1. A positive correlation between DON levels and precipitation was seen. The 70% of wheat samples destined for human consumption were contaminated with DON. To avoid the introduction of contaminated materials into the food chain process, the adoption of regular screening of the DON level in wheat is recommended, particularly in years with heavy rainfall during the flowering-to-early stages of grain maturity months.  相似文献   

5.
This study examined a total of 82 consignments of French and Argentinean raw maize as received at maize mills in the UK between 2004 and 2007. Samples were analysed for deoxynivalenol (DON), nivalenol (NIV), other trichothecenes, zearalenone (ZON), and fumonisins B1, B2, and B3 (FB1, FB2, and FB3) using fully validated analytical methods with limits of quantification of 10 µg kg?1 for DON, NIV, and each fumonisin mycotoxin and 3 µg kg?1 for ZON. All samples except two containing fumonisins met the European Commission statutory maximum permissible levels for DON, ZON, and FB1 + FB2 as operating in 2007. The maximum concentrations found for DON, NIV, ZON, and FB1 + FB2 were 444, 496, 165 and 5002 µg kg?1, respectively. Fumonisins were detected in almost every sample with 65% of Argentinean maize containing more than 1000 µg kg?1 of FB1 + FB2. In contrast, ZON was not detectable in almost 50% of consignments. During this period there was a distinct difference in mycotoxin concentrations between harvests and geographic origin. Flint maize from Argentina usually contained lower concentrations of DON and related trichothecenes and higher levels of fumonisins than maize from France, although concentrations of fumonisins up to 2000 µg kg?1 or greater occurred in samples from both regions. The incidence and concentrations of fumonisins were similar to those in a similar previous survey, while zearalenone concentrations were lower. The distribution of mycotoxins in multi-hold ships was also investigated showing that fumonisins were much more evenly distributed than DON, thus indicating their general level in the ship as a whole. The effect of cleaning regimes was found to be very variable, especially for DON, ranging from no removal of mycotoxins to greater than 50% in some instances, but was not related to concentration. Evidence here suggests that while cleaning is essential for removing foreign bodies before milling, it cannot be used as a reliable tool for reducing mycotoxins.  相似文献   

6.
Pasta was prepared with modifications designed to alter its rate of digestion, including altering the ratio of A- to B-granules, incorporating higher amylose content, and varying the glutenin:gliadin ratio and HMW:LMW glutenin subunit ratio. The effects of these modifications were investigated using an in vitro hydrolysis method. A significant reduction in parameters related to glycaemic index was established for high amylose pastas and pastas with 40% B-granule composition, while most other modifications increased the rate of starch hydrolysis. All effects observed were small in comparison to the effect on glycaemic index previously obtained by addition of soluble fibres.  相似文献   

7.
Insect survival in the presence of contact insecticides may be through physiological mechanisms or avoidance of contact with the compound. Curiously, although the first alternative is the object of frequent attention, the second is often neglected, but both may lead to insecticide resistance. Preliminary evidence for both physiological and behavioral resistance to pyrethroids has been obtained for a few strains of the maize weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). Here we carried out a more comprehensive survey using 15 populations of S. zeamais, by examining a long-used but relatively little studied organophosphate - fenitrothion, recording not only physiological resistance, but also the behavioral responses to exposure. Physiological resistance to fenitrothion among populations of S. zeamais reached low to moderate levels (ranging from 0.9 to 14.1× at the LC50), an increase in resistance levels compared with previous studies. Fenitrothion-induced behavioral avoidance varied among populations, particularly regarding insecticide irritability (i.e., avoidance after contact with fenitrothion), but the behavioral responses observed were mainly stimulus-independent. However, there was no correlation between physiological and behavioral resistance to fenitrothion in S. zeamais populations. Both survival strategies to fenitrothion - facing or fleeing the insecticide exposure, were observed and may co-occur in a single population, emphasizing the need of assessing both responses and their relative importance in designing management programs against stored-product insects.  相似文献   

8.
BackgroundMany studies around the world reported the occurrence of many mycotoxins and their metabolites in human breast milk. However the contamination by aflatoxin M1 and ochratoxin A were the most investigated by several countries.Scope and approachTo scrutinize all papers reporting quantitative data on the prevalence and the levels of mycotoxins and their metabolites in breast milk, also the circumstances of exposure.A systematic literature search in Pubmed, Science direct and Google scholar databases were performed to identify relevant studies, published in English from 1984 through May 2015.Key findings and conclusion63 studies met the inclusion criteria and assessed the occurrence of 29 mycotoxins & their metabolites in breast milk, regarding 7194 subjects of 31 countries. The maternal dietary habits, the socio demographic status of the mother, the seasonal variations and the sensitivity of the analytical method were the factors related to the high concentrations of AFM1 and OTA in breast milk.Studies where contamination exceeds maximum limits and exhibit real risk of public health were highlighted.  相似文献   

9.
10.
The aim of this study was to evaluate the efficiency of presynchronization with GnRH and PGF or with progesterone on overall Ovsynch (OVS) outcomes in noncyclic dairy cows. Cows were scanned 7 d apart with ultrasonography to determine cyclicity. Noncyclic cows (n = 281; no corpus luteum on ovaries at both examinations) were randomly divided into 3 groups. In the GP group (n = 108), the cows received GnRH and PGF (PGF) administrations 7 d apart, and OVS was started 11 d after PGF (GnRH-7 d-PGF-11 d-OVS). In the P4 group (n = 90), the cows were treated for 7 d with an intravaginal progesterone (P4) implant (PRID), and then OVS was started 11 d after removal of the implant (7 d PRID-11 d-OVS). The control group (CON, n = 83) did not receive any presynchronization, and OVS was started at the same time as in the other groups (18 d-OVS). The percentage of cows that became cyclic at the beginning of OVS was lower in the CON group (38.6%; 32/83) than in the presynchronization groups (66.7%, 72/108 in GP; 71.1%, 64/90 in P4). The response to the first GnRH of OVS did not differ among groups (63.9%, 53/83 in CON; 67.6%, 73/108 in GP; 63.3%; 57/90 in P4), and synchronization rates were similar among the groups (74–82%). The cows that responded to presynchronization treatments (GP or P4) had higher pregnancy per artificial insemination (P/AI) than did nonresponding cows. Pregnancy per AI at 31 d did not differ between groups (30.1%, 25/83 in CON; 43.5%, 47/108 in GP; and 35.6%, 32/90 in P4). However, CON cows (24.1%, 20/83) had lower P/AI at 62 d than GP cows (41.7%, 45/108). Embryonic loss was higher in CON (20%, 5/25) compared with the P4 group (3%, 1/32). The administration of GnRH followed by PGF or exogenous progesterone (PRID) similarly increased the percentage of cows that became cyclic before Ovsynch in noncyclic cows, but fertility did not improve. However, the cows that responded to presynchronization had higher fertility rates than the nonresponding cows.  相似文献   

11.
Despite major maize programs in the last two decades and costly investments in a price subsidy program in Ghana, maize productivity remains very low. Utilizing cross-sectional data on 645 maize plots in Ghana, this paper provides empirical evidence on the responsiveness of maize yield to fertilizer application, profitability of fertilizer use, and how the economics of fertilizer use have changed with the subsidy program. There was a statistically significant maize yield response to increased fertilizer application (i.e. 1-kg of nitrogen leads to a yield increase of 22–26 kg per hectare), higher than those estimated in other countries in Africa. Value-cost ratio shows that maize production with fertilizer is profitable both at market and subsidized prices in different locations and with different farming practices, even after incorporating risk into the estimation and analysis. However, despite subsidized prices and profitable fertilizer use, the actual application rate (at 44 kg/ha of nitrogen on average) is much lower than research institute’s and government recommendation and far off the computed economically “optimal” levels (at 225 kg/ha of nitrogen; where the fertilizer price intersects the value of marginal physical product derived from the yield response model). Results suggest that fertilizer prices do not seem to be the binding constraint in greater fertilizer application and productivity increases in maize; other factors appear to be major bottlenecks to greater fertilizer application and productivity increases including accessibility to modern varieties, mechanization, and hired labor. This result shows the limits to fertilizer subsidy as the focus strategy and suggests a more integrated and holistic approach to encourage greater fertilizer application, productivity and income among maize farmers in Ghana.  相似文献   

12.
13.
The aim of this study was to identify and characterise the predominant yeasts in Champús, a traditional Colombian cereal-based beverage with a low alcoholic content.Samples of Champús from 20 production sites in the Cauca Valley region were analysed. A total of 235 yeast isolates were identified by conventional microbiological analyses and by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of ITS1-5.8S rDNA-ITS2. The dominant species were: Saccharomyces cerevisiae, Issatchenkia orientalis, Pichia fermentans, Pichia kluyveri var. kluyveri, Zygosaccharomyces fermentati, Torulospora delbruekii, Galactomyces geotrichum and Hanseniaspora spp. Model Champús systems were inoculated with single strains of some isolated sporogenus species and the aromatic profiles were analysed by SPME. Analysis of data showed that Champús strains produced high amounts of esters. The aromatic compounds produced by Saccharomyces and non-Saccharomyces yeasts from Champús can exert a relevant influence on the sensory characteristics of the fermented beverage. The Champús strains could thus represent an important source for new yeast biotypes with potential industrial applications.  相似文献   

14.
The rheological and thermal properties of wheat dough with the addition of γ-polyglutamic acid (PGA) (0.5, 1.0, 5.0 g kg−1, w/w) was evaluated by the measurements of farinography, rapid visco analysis and differential scanning calorimetry. Adding 5.0 g kg−1 PGA in wheat dough increased the mixing stability and raised the pasting temperature from 75.8 to 84.4 °C, but decreased the peak viscosity and breakdown. The water holding capacity of wheat dough increased with the addition of 5.0 g kg−1 of PGA. At 5.0 g kg−1 level, PGA caused significant declines in the enthalpy, onset and peak temperatures of ice-melting transition of wheat dough. Scanning electron microscopy showed that wheat bread with the addition of 1.0 and 5.0 g kg−1 PGA exhibited microstructures with smoother surfaces. During storage, PGA retarded the staling process of wheat bread.  相似文献   

15.
Benzoic acid and sorbic acid are widely used for food preservation. These preservatives are generally recognised as safe. The aim of this study was to determine the level of benzoic and sorbic acid in food samples that are usually consumed in Iran. Therefore, 54 samples, including 15 soft drinks, 15 ultra-high-temperature milk, 15 ketchup sauces and 9 bread samples, were analysed by high-performance liquid chromatography with UV detection. Benzoic acid was detected in 50 (92.5%) of the samples ranging from 3.5 to 1520 µg mL?1, while sorbic acid was detected in 29 (50.3%) samples in a range of 0.8 and 2305 µg mL?1. Limits of detection and limits of quantification for benzoate were found to be 0.1 and 0.5 µg mL?1, respectively, and for sorbate 0.08 and 0.3 µg mL?1, respectively. The results showed that benzoic acid and sorbic acid widely occur in food products in Iran.  相似文献   

16.
17.
Gelling mixtures of Na+κ-carrageenan with whey protein isolate (WPI) at pH 7.0 have been studied rheologically and by differential scanning calorimetry (DSC), with comparative measurements for the individual constituents of the mixtures. The concentration of WPI was held fixed at 10.0 wt% and carrageenan concentration was varied in the range 0.05–3.0 wt%. Ca2+ cations, which have been shown previously to be particularly effective in inducing gelation of κ-carrageenan, were introduced as CaCl2. The concentration of CaCl2 used in most of the experiments was 8 mM, but other concentrations were also studied. Mixtures were prepared in the solution state at 45 °C, and showed no evidence of either phase separation or complex formation. Rheological changes were monitored by low-amplitude oscillatory measurements of storage modulus, G′, during (i) cooling (1 °C/min) and holding at 5 °C, to induce gelation of the carrageenan in the presence of non-gelled WPI; (ii) heating and holding at 80 °C to dissociate the carrageenan network and induce gelation of WPI; (iii) cooling and holding again at 5 °C, to give composite networks with both components gelled; and (iv) re-heating to 80 °C to dissociate the carrageenan network. Gel structure was characterised further by creep–recovery measurements at the end of each holding period, and by torsion measurements at 5 °C, before and after thermal gelation of WPI.  相似文献   

18.
A study of aflatoxin (AF) exposure and the levels of vitamins A and E was carried out with a group of 507 Ghanaian participants. AFB1–albumin adducts (AFB-AA) were measured by radioimmunoassay and vitamins A and E were measured by high-performance liquid chromatography (HPLC). The average level of serum AFB-AA was 0.94 ± 0.64 (range = 0.1–4.44) pmol mg?1 albumin. Mean levels of vitamins A and E were 1.32 ± 0.48 (range = 0.41–4.85) µmol l?1 and 15.68 ± 4.12 (range = 6.35–30.40) µmol l?1, respectively. A significantly negative correlation was found between serum AFB-AA and vitamin A levels (r = ?0.110, p = 0.013). An even stronger, significant negative, correlation was found between serum AFB-AA and vitamin E levels (r = ?0.149, p < 0.001). Serum AFB-AA levels were statistically higher (median = 0.985 pmol mg?1 albumin) in subjects who had low levels of both vitamins A and E as compared with the levels (median = 0.741 pmol mg?1 albumin) subjects who had high vitamins A and E levels (p trend = 0.001). To verify these findings, blood samples were again collected from 165 of the 507 people 3 months after the initial collection. Significantly negative correlations were confirmed between levels of serum AFB-AA and both vitamins A (r = ?0.232, p = 0.003) and E (r = ?0.178, p = 0.023). Again, high serum AFB-AA concentrations (median = 1.578 pmol mg?1 albumin) were found in subjects with low levels of vitamins A and E compared with the concentrations (median = 1.381 pmol mg?1 albumin) in subjects with high levels of vitamins A and E (p trend = 0.002). These data show that AF exposure was associated with decreased levels of serum vitamins A and E in high-risk human populations, which may significantly influence the incidence of AF-related adverse health effects.  相似文献   

19.
Two proteinases, a neutral proteinase from Bacillus subtilis and a cysteine proteinase from Micrococcus sp., were used to accelerate the ripening process of raw cow's milk Hispánico cheese, a semihard variety. Two levels (0.1% and 1%) of a commercial starter culture containing Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris were added for cheese manufacture. The influence of both factors, proteinase addition and level of starter culture, on the growth of amino acid-decarboxylating microorganisms and on the formation of biogenic amines during cheese ripening was investigated in duplicate experiments. The population of tyrosine decarboxylase-positive bacteria, which represented less than 1% of the total bacterial population in most cheese samples, and tyrosine decarboxylase-positive lactobacilli was not influenced by proteinase addition or level of starter culture. Tyramine was detected in all batches of cheese from day 30. Its concentration was significantly (P < 0.05) influenced by proteinase addition but not by the level of starter culture and increased with cheese age. After 90 days of ripening, 103 to 191 mg/kg of tyramine was found in the different cheese batches. Histamine was not detected until day 60 in cheese with neutral proteinase and 1% starter culture and until day 90 in the rest of the cheeses. The concentration of this amine did not exceed 20 mg/kg in any of the batches investigated. Phenylethylamine and tryptamine were not found in any of the samples.  相似文献   

20.
We investigated the effects of Monascus-fermented mixed grain extracts (MFGEs) enriched with bioactive mevinolins (natural statins) and coenzyme Qs (CoQ9 + CoQ10) on the blood lipids, antioxidant status, and tissue levels of CoQs and α-tocopherol (α-Toc) in hyperlipidemic rats. The oral administration of MFGEs (300 mg/kg body weight per day) for 8 weeks resulted in a significant decrease in blood levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and LDL-C/high-density lipoprotein cholesterol (HDL-C) ratio compared to the control and lovastatin supplement group of a dosage of 20 mg/kg per day (p < 0.05). Furthermore, a significant increase in the ratios of α-Toc/LDL-C and CoQs/LDL-C in plasma and tissues and improvement in plasma antioxidant status as measured by TBARS and TRAP were observed in hypercholesterolemic rats (p < 0.05). Regarding the effects of MFGEs on antioxidant levels of plasma and tissues, there were significant increases in the levels of α-Toc (p < 0.05) and CoQs (p < 0.01) after the 8-week MFGEs treatment. These data indicate that MFGEs supplementation not only decreases blood lipids and lipid peroxidation but also increases levels of antioxidants such as α-Toc and CoQs and may improve plasma antioxidant status as well as a hypolipidemic effect.  相似文献   

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