首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Thirty-five samples of poultry feeds and corresponding raw materials (maize, soybean and meat meal) from a processing plant were analyzed to evaluate the distribution and toxigenicity of Aspergillus section Flavi isolates. Mycological analysis of the samples indicated the presence of five fungal genera (Aspergillus, Penicillium, Fusarium, Cladosporium, and Eurotium). Aspergillus flavus was the predominant species being present in 48.5% of the analyzed samples. Ninety-one isolates belonging to Aspergillus section Flavi were isolated; ninety were identified as A. flavus and only one as A. parasiticus. Fifty-seven isolates were capable of producing sclerotia, 41 were identified as L-type strains and 16 as type S. Fifty-seven percent of the isolates produced AFB1 levels ranging from 0.05 μg/kg to 27.7 μg/kg whereas 86.8% produced CPA from 1.5 μg/kg to 137.8 μg/kg. L-strains produced from 0.05 to 14.8 μg/kg of aflatoxin and type S produced levels from 0.05 to 1.65 μg/kg. No significant differences in CPA production among S- and L-strains were observed. Sclerotial isolates produced AFB1 levels ranging between 0.05 and 27.7 μg/kg and CPA levels from 3.8 to 47.3 μg/kg. More than half of the A. flavus isolates were able to produce AFB and CPA simultaneously. Twenty percent of the 35 samples were contaminated with aflatoxin B1 whereas 34.3% were contaminated with CPA. The high rate of CPA producing isolates represents a potential risk of contamination with this toxin in poultry feeds.  相似文献   

2.
Aflatoxin contents of cereals and nuts, collected from local markets of NWFP, were determined by thin layer chromatography (TLC). The seeds of these crops were also inoculated with Aspergillus flavus and the aflatoxin content and its relation with the proximate composition of seeds was studied. The effect of storage for different durations of time (2–3 and 12–18 months) on the aflatoxin content of seeds was also assessed. Aflatoxin content of cereals (wheat, maize and rice) ranged from 14 to 45 μg/kg, and that of nuts (almond, walnut and peanut) varied from 5 to 17 μg/kg. The aflatoxin content was within the safe limit (50 μg/kg) recommended by FAO. The aflatoxin content of inoculated seeds was significantly (p < 0.05) increased over control (un-inoculated seeds). This was positively related (r = 0.65) to moisture content of the seeds. However, negative correlation (r = −0.50) existed between aflatoxin and ash contents of the seeds. Protein, fat and total carbohydrate (NFE) contents were not much affected by inoculation. Prolonged storage for 18 months (1.5 years) significantly (p < 0.05) increased aflatoxin contents of seeds compared to short storage periods (2–3 months). It was concluded that aflatoxin content of food should be monitored to ensure food safety. Prolonged storage of cereal and nuts in warm humid condition should be avoided to minimize the risk of aflatoxin contamination.  相似文献   

3.
In a multicenter study conducted by the Indian Council of Medical Research, 1,646 samples of wheat grain collected from rural and urban areas of 10 states representing different geographical regions of India were analyzed for aflatoxin B1 (AFB1). AFB1 concentrations of > or = 5 microg kg(-1) were recorded in 40.3% of the samples, and concentrations above the Indian permissible regulatory limit of 30 microg kg(-1) were found in 16% of the samples. The proportion of samples with AFB1 concentrations above the Indian regulatory limit ranged from 1.7 to 55.8% in different states, with the minimum in Haryana and the maximum in Orissa. The variation in wheat contamination among states seems to be mainly the result of unsatisfactory storage conditions. Median AFB1 concentrations of 11, 18, and 32 microg kg(-1) were observed in samples from Uttar Pradesh, Assam, and Orissa, respectively; concentrations in other states were <5 microg kg(-1). The maximum AFB1 concentration of 606 microg kg(-1) was observed in a sample from the state of Uttar Pradesh. The calculated probable daily intakes of AFB1 through consumption of contaminated wheat for the population in some states were much higher than the suggested provisional maximum tolerable daily intake. Human health hazards associated with such AFB1 exposure over time cannot be ruled out.  相似文献   

4.
The objective of this study was to compare the effect of different storage moisture conditions (0.70, 0.85, 0.90 and 0.95 water activity, aw) and temperatures (20, 25, 30 °C) on (a) respiration rates (R) and dry matter loss (DML) of paddy and brown rice and (b) quantify aflatoxin B1 (AFB1) production by isolates of Aspergillus flavus from the rice samples and (c) inoculation of both rice types with A. flavus under these storage conditions on R, DML and AFB1 contamination. There was an increase in temporal CO2 production with wetter and warmer conditions in naturally contaminated rice. Higher R and consequently, % DML, were generally found in the brown rice (21%) while in paddy rice this was only up to 3.5% DML. From both rice types, 15 (83.3%) of 18 A. flavus isolates produced detectable levels of AFB1 in a range 2.5–1979.6 μg/kg. There was an increase in DML in both rice types inoculated with A. flavus as temperature and aw were increased. Interestingly very little AFB1 was detected in paddy rice, but significant contamination occurred in the brown rice. The %DML in the control and A. flavus inoculated rice increased with temperature and aw at both 25 and 30 °C from 1-2% to 15–20% DML at 30 °C and 0.95 aw. All the inoculated rice samples had AFB1 levels above the EU legislative limits for contamination in other temperate cereals and products derived from cereals (=2 μg/kg). Even samples with % DML as low as 0.2% had AFB1 contamination levels twice the limits for other cereals. These results suggest that the mycotoxin contamination risk in staple commodities like rice, is influenced by whether the rice is processed or not, and that measurement of R rates can be used to predict the relative risk of AFB1 contamination in such staple commodities.  相似文献   

5.
Distribution of fungi and aflatoxins in a stored peanut variety   总被引:1,自引:0,他引:1  
The objective of the present study was to evaluate the mycoflora and occurrence of aflatoxins in stored peanut samples (hulls and kernels) from Tupã, State of São Paulo, Brazil. The samples were analyzed monthly over a period of one year. The results showed a predominance of Fusarium spp. (67.7% in hulls and 25.8% in kernels) and Aspergillus spp. (10.3% in hulls and 21.8% in kernels), and the presence of five other genera. The growth of Aspergillus flavus was mainly influenced by temperature and relative humidity. Analysis of hulls showed that 6.7% of the samples were contaminated with AFB1 (mean levels = 15–23.9 μg/kg) and AFB2 (mean levels = 3.3–5.6 μg/kg); in kernels, 33.3% of the samples were contaminated with AFB1 (mean levels = 7.0–116 μg/kg) and 28.3% were contaminated with AFB2 (mean levels = 3.3–45.5 μg/kg). Analysis of the toxigenic potential revealed that 93.8% of the A. flavus strains isolated were producers of AFB1 and AFB2.  相似文献   

6.
Malaysian population widely consumes the cereal-based foods, oilseeds, nuts, and spices in their daily diet. Mycotoxigenic fungi are well known to invade food products under storage conditions and produce mycotoxins that have threat to human and animal health. Therefore, determining toxigenic fungi and aflatoxin B(1) (AFB1) in foods used for human consumption is of prime importance to develop suitable management strategies and to minimize risk. Ninety-five food products marketed in Penang, Malaysia were randomly collected from different supermarkets and were analyzed for presence of Aspergillus spp. by agar plate assay and AFB1 by enzyme-linked immunosorbent assay (ELISA). A. flavus was the dominant fungi in all foods followed by A. niger. Fifty-five A. flavus strains were tested for their ability to produce aflatoxins on rice grain substrate. Thirty-six (65.4%) strains out of 55 produced AFB1 ranging from 1700 to 4400 μg/kg and 17 strains (31%) produced AFB2 ranging from 620 to 1670 μg/kg. Natural occurrence of AFB1 could be detected in 72.6% food products ranging from 0.54 to 15.33 μg/kg with a mean of 1.95 μg/kg. Maximum AFB1 levels were detected in peanut products ranging from 1.47 to 15.33 μg/kg. AFB1 levels detected in all food products were below the Malaysian permissible limits (<35 μg/kg). Aspergillus spp. and AFB1 was not detected in any cookies tested. Although this survey was not comprehensive, it provides valuable information on aflatoxin levels in foods marketed in Malaysia.  相似文献   

7.
Contamination of barley by moulds and mycotoxins results in quality and nutritional losses and represents a significant hazard to the food chain. The presence of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) and ochratoxin A (OTA) in stored barley in Spain has been studied. Species-specific PCR assays were used for detection of Aspergillus flavus, A. parasiticus, A. ochraceus, A. steynii, A. westerdijkiae, A. carbonarius and A. niger aggregate in mycotoxin-positive barley samples at different incubation times (0, 1 and 2 days). Classical enumeration techniques (CFU/g) in different culture media for evaluation of Aspergillus in sections Flavi, Circumdati and Nigri were also used. One hundred and five barley kernel samples were collected in Spanish grain stores from 2008 to 2010, and analyzed using a previously optimized method involving accelerated solvent extraction, cleanup by immunoaffinity column, liquid chromatographic separation, post-column derivatization with iodine and fluorescence detection. Twenty-nine samples were contaminated with at least one of the studied mycotoxins. AFB1, AFB2, AFG1, AFG2, and OTA were detected in 12.4%, 2.9%, 4.8%, 2.9%, and 20% of the samples, respectively. Aflatoxins and OTA co-occurred in 4.8% of the samples. Maximum mycotoxin levels (ng/g) were 0.61 (AFB1), 0.06 (AFB2), 0.26 (AFG1), 0.05 (AFG2), and 2.0 (OTA). The results of PCR assays indicated the presence of all the studied species, except A. westerdijkiae. The PCR assays showed high levels of natural contamination of barley with the studied species of Aspergillus which do not correspond to the expected number of CFU/g in the cultures. These results suggest that a high number of non-viable spores or hyphae may exist in the samples. This is the first study carried out on the levels of aflatoxins and OTA in barley grain in Spain. Likewise, this is the first report on the presence of aflatoxigenic and ochratoxigenic Aspergillus spp. in barley grain naturally contaminated with those mycotoxins using a species-specific PCR approach.  相似文献   

8.
Natural infection of cowpea by toxigenic fungi and mycotoxin contamination in Benin, West Africa were studied. Cowpea samples were collected at harvest (T0) and after three months of storage (T3) from the four agro-ecological zones of the country. A total of 92 representative samples were analysed for the two periods. About 23 fungal species were identified on cowpea seed samples across zones of which Aspergillus flavus, a fungus that produces aflatoxins, was most frequently encountered. Fusarium species shown to produce fumonisins were not recorded from cowpea seeds. Overall incidence of A. flavus infection was found to increase after storage from 7.6% at T0 to 28.25% at T3. In spite of this natural infection of cowpea, very low levels of fumonisin and aflatoxin were detected. Only three out of the 92 cowpea samples, all collected at T0, were found to be fumonisin B1 positive with a mean level of 0.03 μg/g. Similarly, only six samples out of the 92, all collected at T3, were aflatoxin B1 positive with mean levels of 3.58 μg/kg. Fumonisin (B2 and B3) and aflatoxin (B2, G1 and G2) were not detected in any of the samples. Contrary to the situation with maize and groundnut where high levels of toxin are often detected in naturally infected samples, the current results indicate that cowpea is less susceptible to mycotoxin contamination. A low susceptibility could be due to the presence in cowpea of substances that inhibit mycotoxin biosynthesis. Further investigations are underway to confirm this hypothesis.  相似文献   

9.
In this work, we have investigated about the presence of several natural stilbenes in 12 samples of pistachios harvested from 10 different farms of Sicily (Bronte and Agrigento). At the same time, we have evaluated the relation between the stilbenes synthesis and the possible contamination of mycotoxin produced by Aspergillus flavus and Aspergillus parasiticus. We have found two types of stilbenes in the samples of pistachios examined: trans-resveratrol and trans-resveratrol-3-O-β-glucoside (trans-piceid). Their concentration ranged from 0.07 to 0.18 mg/kg (av. = 0.12 ± 0.03 mg/kg) for trans-resveratrol, from 6.20 to 8.15 mg/kg (av. = 6.97 ± 0.55 mg/kg) for trans-piceid and from 6.38 to 8.27 mg/kg (av. = 7.09 ± 0.54 mg/kg) for total resveratrol.  相似文献   

10.
Under a multi-centre study conducted by the Indian Council of Medical Research, 1,511 samples of parboiled rice were collected from rural and urban areas of 11 states representing different geographical regions of India. These samples were analysed for contamination with aflatoxin B(1.) The presence of aflatoxin B(1) at levels=5 microg g(-1) was found in 38.5% of the total number of samples of the parboiled rice. About 17% of the total samples showed the presence of aflatoxin B(1) above the Indian regulatory limit of 30 microg kg(-1). No statistically significant difference in percentage of samples contaminated with >30 microg kg(-1) was observed between pooled rural (19.4%) and urban (14.5%) data. A median value of 15 microg kg(-1) of aflatoxin B(1) was observed in samples from Assam, Bihar and Tripura. In all other states surveyed the median value was <5 microg?kg(-1).  相似文献   

11.
12.
BACKGROUND: Sorghum (Sorghum bicolor (L.) Moench) is an important coarse cereal crop grown for grain and fodder in the semi‐arid Tropics, mainly in Asian and African countries. In India sorghum is consumed as human food and poultry feed. Sorghum grain grown in the rainy season (kharif) is becoming severely affected by grain moulds, the major fungi involved being Aspergillus, Fusarium and Curvularia. If the extent of mould is severe, the grain is unsafe for consumption owing to contamination by mycotoxins. RESULTS: This paper presents a multi‐centre study conducted in sorghum to evaluate natural contamination of aflatoxin B1 in India. A total of 1606 grain sorghum samples were collected during the rainy (kharif) season across 4 years from seven states of India, representing different geographical regions of the country. Aflatoxin B1 contamination during 2007–08 was the highest (13.1%), followed by samples from the year 2004–05 (2.85%). The samples collected in years 2005–06 and 2006–07 showed contamination below 1%. The number of samples (35) showing aflatoxin B1 contamination above the safety limit was also highest during 2007–08 as compared to samples from the other years. CONCLUSION: This study, conducted for 4 years, showed that natural contamination of aflatoxin B1 in sorghum grown in India is within safety limits (20 µg kg?1) recommended by the Codex Alimentarius Committee and 73% of samples were positive for toxin. However, 0.75% (12) of total samples contained aflatoxin above the safety limit. The overall occurrence of toxin from Madhya Pradesh and Rajasthan was below 5 µg kg?1. Copyright © 2012 Society of Chemical Industry  相似文献   

13.
A survey for total aflatoxins (aflatoxins B1, B2, G1, and G2) was conducted on 88 spices and processed spice products commercialized in Korea. The presence of aflatoxins was determined by high-performance liquid chromatography (HPLC) with fluorescence detector using immunoaffinity column clean-up. Total aflatoxins (AFs) are detected in 12 samples (13.6% of incidence) including seven red pepper powder, two red pepper pastes (Kochujang), two curry and one ginger product. The contamination levels are 0.08–4.45 μg/kg as aflatoxin B1 and 0.08–4.66 μg/kg as AFs. The liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis on contaminated samples was conducted for the confirmation of detected aflatoxins. The 12 samples which showed aflatoxins by HPLC/FLD were confirmed as aflatoxins by LC–MS/MS.  相似文献   

14.
Aflatoxins were surveyed in 256 rice samples taken from retail markets in different provinces of Iran during October 2007 and July 2008. A methanol/water (80?:?20,?v/v) mixture and an aflatoxin immunoaffinity column (IAC) were used for extraction and clean-up. Mycotoxins were determined using HPLC with fluorescence detection and post-column derivatization using a photo-ionization cell. Levels of contamination ranged 0.0–5.8?ng?g?1 (mean, 1.4?ng?g?1) and 0.1–6.3?ng?g?1 (mean, 1.6?ng?g?1) for AFB1 and total aflatoxins, respectively. AFB1 was detected in almost all samples. Results showed that 55 samples (21.5%) were contaminated with more than 2?µg?kg?1 of AFB1, while seven samples (2.7 %) contained more than 4?µg?kg?1 total aflatoxins. The calculated probable daily intake of AFB1 from rice for Iranians ranged 1.4–5.8?ng AFB1 per kg body weight per day for average consumers and, hence. exceeding the estimated provisional maximum tolerable daily intake.  相似文献   

15.
《Nigerian Food Journal》2014,32(1):73-79
Aflatoxin contamination of animal feeds is common and widely spread, especially in the tropics, due to the ubiquity of the producing fungi. The detection of aflatoxin in five samples of animal feed was carried out; using enzyme linked immunosorbent assay (ELISA). Samples were taken from five different areas in Abeokuta. The aflatoxin level was observed to be the highest in the poultry feed from Lafenwa with the value 93.1 μg/kg; and lowest in the feed from Idi-Aba with the value 13.5 μg/kg. Fungal counts are between 4 × 103 and 42 × 103 cfu/g, with highest count occurring in the feed from Lafenwa and lowest in Idi-Aba. The fungal growth was on potato dextrose agar (PDA), and Aspergillus flavus, A. oryzae, Rhizopus oryzae and Penicillum notatum were isolated and identified, with Aspergillus flavus predominating. Comparison statistical analysis using ANOVA showed a significant mean difference 95% confidence interval. In conclusion, aflatoxin was present in all the samples, which even at low concentration is of great concern to human and animal health. Maize was the main ingredient in all the contaminated feed.  相似文献   

16.
Synthesised E- and Z-ajoene were used to determine their amounts in food oils containing various fresh garlics. The best yield of E-ajoene (172.0 μg/g of garlic) and Z-ajoene (476.0 μg/g of garlic) was obtained from freshly prepared Japanese garlic with rice oil which was heated at 80 °C. Determination of E- and Z-ajoene from soybean oil containing 15% Japanese garlic samples prepared at 80 °C for 0.5 h gave the amount of E-ajoene (170.0 μg/g of garlic) and Z-ajoene (127.0 μg/g of garlic). After 9-month storage, 54.0% E- and 11.0% Z-ajoene remained in Japanese garlic with rice oil. Ajoene (0.1 mM) in ethyl acetate was incubated under UV-light (253.7 nm) for 3 days, 81.7% E- and 56.9% Z-ajoene remained. 4.3% and 0.5% E- and Z-ajoene remained when ajoene (0.1 mM in ethyl acetate) was incubated at 100 °C.  相似文献   

17.
This study investigated the effect of a modified yeast cell wall extract preparation (YCW) on the excretion of aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1) in feces, urine, and milk of dairy ewes fed an aflatoxin-contaminated diet. Sixteen ewes in mid-lactation were assigned to 4 treatment groups: control, AF (60 μg of AFB1/kg of feed), YCW (2 g/kg of feed), and AF+YCW. The trial consisted of a short-term (3-d) exposure period followed by a long-term (21-d) exposure period. At the end of each exposure period, milk, urine, and feces were collected over 72 h. The treatments did not affect feed intake, milk production, milk composition, or body weight. The presence of AFM1 was detected in all matrices, whereas AFB1 was only present in feces. Daily excretion was higher following long-term exposure and reached 26.9 μg of AFB1/d in feces, 37.2 μg of AFM1/d in feces, and 10.7 μg of AFM1/d in urine. Supplementation with YCW was effective in increasing aflatoxin excretion in feces in the long-term exposure (up to 156% increase). The effect was accompanied by a trend of decreasing urinary excretion of AFM1. In contrast, the addition of YCW to the contaminated diet did not affect the transfer of aflatoxins from feed to milk under the present experimental conditions with low-producing ewes. The transfer rates of AFM1 in milk ranged from 0.24 to 0.54%. In conclusion, feed supplementation with YCW reduced the absorption of AFB1 and increased the elimination of AFB1 and AFM1 in ewe feces. Yeast cell wall extract could be used to protect ruminants from chronic exposure to aflatoxins present in feeds.  相似文献   

18.
Experiments were conducted to determine the potential for biological control of aflatoxin contamination of peanuts during storage. Florunner peanuts were treated in field plots by applying competitive, nontoxigenic strains of Aspergillus flavus and A. parasiticus, at 76 and 67 days after planting in 1998 and 1999, respectively. After harvest, half the peanuts from both treated and control plots were sprayed with an aqueous conidial suspension containing the nontoxigenic strains; the other half of the peanuts from each group were not sprayed. The peanuts were then placed in separate compartments of a miniature warehouse. Therefore, storage treatments consisted of peanuts that were (1) not treated at all; (2) treated prior to storage only; (3) field-treated only; (4) treated both in the field and prior to storage. Peanuts were stored for 3-5 months under high temperature and relative humidity conditions designed to promote aflatoxin contamination. In 1998, peanuts were not contaminated with aflatoxins prior to storage. After storage, peanuts that were never treated with the competitive fungi contained an average of 78.0 ppb of aflatoxins. Peanuts not treated in the field but receiving the spray treatment before storage contained 48.8 ppb. Peanuts treated in the field only averaged 1.4 ppb, and peanuts treated both in the field and prior to storage contained 0.8 ppb. In 1999, peanuts suffered from late-season drought and were contaminated with aflatoxins at harvest, with controls averaging 516.8 ppb compared with 54.1 ppb in treated peanuts. After storage, non-field-treated peanuts averaged 9145.1 ppb compared with 374.2 ppb for peanuts that had been field-treated, a 95.9% reduction. Spraying of pods with the nontoxigenic strains postharvest but prior to storage provided no additional protection against aflatoxin contamination. Results demonstrated that field application of the nontoxigenic strains had a carry-over effect and reduced aflatoxin contamination that occurred in storage.  相似文献   

19.
An experiment was carried out using dairy ewes to study the transfer of aflatoxin B1 (AFB1) from feed to milk and from milk to cheese. The effects of AFB1 on liver function and hematological parameters were also investigated. Fifteen ewes were assigned to treatments in replicated 3 × 3 Latin squares. The experimental groups received 32, 64, or 128 μg/d of pure AFB1 for 7 d followed by 5 d of clearance. On the sixth day of the first period, the total daily milk produced by each ewe was collected separately and processed into cheese. The results indicate that the level of AFB1 used did not adversely affect animal health and milk production traits. The aflatoxin M1 (AFM1) concentrations in milk approached a steady-state condition in all treated groups between 2 and 7 d after the start of treatment. The mean AFM1 concentrations of treated groups in steady-state condition (184.4, 324.7, and 596.9 ng/kg in ewes fed 32, 64, or 128 μg of AFB1, respectively) were significantly affected by the AFB1 doses. The AFM1 concentration was linearly related to the AFB1 intake/kg of BW. The carry-over values of AFB1 from feed into AFM1 in milk (0.26 to 0.33%) were not influenced by the AFB1 doses. The AFM1 concentrations in curd and whey were linearly related to the AFM1 concentrations in the unprocessed milk.  相似文献   

20.
Variation in acrylamide content of two Indian traditional products, chapatti and poori was observed with respect to the damaged starch content in whole wheat flour of different wheat varieties from which these products were prepared. Wheat cultivar ‘lokwan’ was milled by altering mill aperture, feed rate and moisture content to obtain whole wheat flour with damaged starch contents ranging from 6.23% to 28.12%. Acrylamide content of the chapatti and pooris prepared from such flours ranged from 12.5 to 65.5 μg/kg in chapatti, and 25.5 to 130.5 μg/kg in pooris. Impact of several additives showed 10 μmol/g flour citric acid, and 100 μmol/g flour calcium chloride to reduce acrylamide in pooris by approximately 54% and 72%, respectively, without altering the sensory analysis of the products.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号