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1.
《Food Control》2013,31(2):596-601
Peanut cake samples were collected from major markets in five states of Nigeria and evaluated for incidence of toxigenic Aspergillus section Flavi populations, and aflatoxin B1 (AFB1) levels by liquid chromatography tandem mass spectrometry (LC–MS/MS). The awareness of consumers to the presence of aflatoxin in the snack and potential health risks of its regular ingestion was evaluated by questionnaire analysis. Aspergillus section Flavi populations were recovered from 83% of the peanut cake samples. Aspergillus flavus L-strain was the most predominant (>56%) across the states while Aspergillus tamarii had the least mean incidence (2.7%). The incidence of atoxigenic strains was significantly (p < 0.05) higher than that of toxigenic strains in samples from Lagos and Kaduna, while the toxigenic strains had a significantly (p < 0.05) higher incidence than the atoxigenic strains in Niger. All analyzed cake samples contained AFB1 in concentrations exceeding the NAFDAC recommended level for AFB1 in food and reaching up to 2824 μg/kg. There was a weak positive correlation (r = 0.32, p = 0.03) for the relationship between the incidence of toxigenic strains in the samples and AFB1 concentration. The consumer awareness data showed that 64% of the respondents consumed peanut cake; majority of who are youth of economic and reproductive age. Eighty-five percent of the consumers lacked awareness of aflatoxin contamination in the snack and possible health risks associated with its ingestion.  相似文献   

2.
Aflatoxin B1 (AFB1) mostly produced by Aspergillus flavus and Aspergillus parasiticus, is an extremely toxic and carcinogenic metabolite. Currants are used in the Mediterranean diet as a food with antioxidant properties. Four strains of Aspergillus section Nigri have been isolated from currants originated from Crete and Corinth. In this study AFB1 production by A. parasiticus and the four strains of Aspergillus section Nigri in Cretan and Corinthian currants (Vitis vinifera L.) is investigated. AFB1 determination was performed by HPLC–FID. Results revealed that the four strains Aspergillus section Nigri, as well as the aflatoxigenic strain A. parasiticus produced AFB1 (0.0052–1.31 μg AFB1 15 g−1, corresponding to 0.0003–0.087 μg AFB1 g−1) in both type of currants (Cretan and Corinthian) on the 12th day of observation. Moreover, AFB1 production, by A. parasiticus in the synthetic Yeast Extract Sucrose (YES) medium was also studied. The ability of AFB1 production has been affected by the special characteristics of each isolate and the currants substrate.  相似文献   

3.
The decontamination of Aflatoxin B1 (AFB1) by immobilized cells of a new mutant strain, prepared on a base of HSCAS (hydrated sodium calcium aluminosilicate), was studied. Novel strains were induced by UV irradiation, from which 50 were screened according to their degradation efficacy on AFB1, compared with the wild strain (FS-Z1). The FS-UV1 strain exhibited highest degradation efficacy, which was confirmed by 18SrDNA to be Aspergillus niger. The results indicate that both immobilized cells and this mutant strain which are incubated for 48 h at 30 °C, would considerably remediate AFB1 in nutrient broth culture, by 95.32% and 82.43%, respectively. By the application of samples of contaminated cottonseed meal, with results of 93.46%∼96.82%, the degradation rate was also validated. The results of Ames test indicate the mutagenic activity of treated AFB1 is greatly abated, with treated controls. The Application of LC-q-TOFMS (liquid-chromatography, quadrupole, time-of-flight mass spectrometry) deduces the structure and molecular formulas of the degradation products. In the vivo study, the damages of photomicrographic evidence are decreased in kidney and liver and the serum biochemical parameters is improved, in response to preventative treatment with immobilized cells. This is the application of HSCAS-prepared, immobilized A. niger cells to degrade AFB1 of contaminated samples. The investigation in this paper offers a novel path for economical, time-saving biodegradation of AFB1 in foods and feeds.  相似文献   

4.
The objective of this study was to gain information about the toxigenic Aspergillus species present in a wide survey of retail samples of paprika and chilli collected in Spain. Detection of these mycotoxigenic species was performed with an optimized protocol for paprika and chilli which includes a set of species-specific PCR assays. Occurrence of toxigenic Aspergillus species was higher in paprika than in chilli samples (83.9% and 64.5%, respectively). Paprika showed also the highest percentage of co-occurrence of two or more different species (43.6%) in comparison with chilli (35.5%). The most common aspergilli were Aspergillus niger aggregate (67.7%), followed by Aspergillus flavus (49.5%). Aspergillus carbonarius, Aspergillus parasiticus and Aspergillus steynii were detected at lower frequency (1.1%). The high co-occurrence of Aspergillus species able to produce ochratoxin A and aflatoxins, particularly in paprika, suggested the need of a more efficient control during processing and storage to reduce fungal contamination, and additional legislation to consider the simultaneous presence of both toxins in these matrices.  相似文献   

5.
Detailed investigation on the effect of gamma (γ) irradiation on germination, sporulation, and growth of aflatoxigenic moulds (Aspergillus parasiticus 2999, Aspergillus flavus 305, and Aspergillus niger 388), as well as on the reduction of aflatoxin B1 (AFB1) level in artificially and naturally contaminated maize/feed samples was performed. The results of in vitro and in situ experiments with aflatoxigenic moulds demonstrated that 5 kGy-γ irradiation manages to prevent sporulation, germination and growth of the tested moulds both when in form of a pure and when in form of a mixed culture. In the feed samples artificially contaminated with AFB1 (50 μg kg−1) 5 kGy-γ irradiation reduced AFB1 level by around 60%, while 10 kGy-dose reduce it for around 85%. Similarly, in feed samples spiked with AFB1 in the concentrations of 100 μg kg−1 5 kGy-dose reduced the AFB1 level by approximately 70%, while the dose of 10 kGy reduced it by approximately 90%. The experiments on naturally contaminated maize samples (n = 30) confirmed these observations; following a 5 kGy-irradiation, the overall mean AFB1 reduction equalled to 69.8%, while the irradiation with a 10 kGy-dose achieved the overall mean toxin reduction of 94.5%. The obtained results indicate that γ irradiation can be used to prevent the growth of aflatoxigenic moulds and to reduce the AFB1 levels in various goods intended for animal and human consumption, thus minimizing the animal and human exposure to this carcinogenic mycotoxin.  相似文献   

6.
《Food Control》2005,16(5):445-450
Possible interferences by different fungal metabolites were studied in order to optimise fluorescent response enhancement of aflatoxins by addition of cyclodextrins. A number of 10 culture media traditionally used for mold and yeasts culture and their enumeration were added with two concentrations of a methyl derivative of β-cyclodextrin. Representative five aflatoxigenic and four non-aflatoxigenic strains of Aspergillus flavus group along with 23 other Aspergillus species were cultured at 28 °C. In all cases, green-bluish fluorescence over all colonies of the aflatoxigenic strain was observed under UV light, this fluorescence was never displayed by any of the other cultured strains.  相似文献   

7.
The potential of certain plant extracts and biocontrol agents for the reduction of aflatoxin B1 (AFB1) in stored rice was investigated. Among the plant extracts tested, Syzigium aromaticum (5 g/kg) showed complete inhibition of Aspergillus flavus growth and AFB1 production. Curcuma longa, Allium sativum and Ocimum sanctum also effectively inhibited the A. flavus growth (65–78%) and AFB1 production (72.2–85.7%) at 5 g/kg concentration. Among the biocontrol agents, culture filtrate of Rhodococcus erythropolis completely inhibited the AFB1 production at 25 ml/kg concentration. The other biocontrol agents, Pseudomonas fluorescens, Trichoderma virens and Bacillus subtilis showed 93%, 80% and 68% reduction of A. flavus growth and 83.7%, 72.2% and 58% reduction of AFB1 at 200 ml/kg, respectively.  相似文献   

8.
Aflatoxins are type of mycotoxins mainly produced by Aspergillus flavus and a common contaminant of food and grain, posing a serious economic and health problem worldwide. In order to find efficient bacteria to remove or detoxify these mycotoxins, a bacterial strain capable of degrading aflatoxin B1 (AFB1) was isolated from soil samples using a culture medium containing coumarin as the sole carbon source. Based on 16S rRNA gene sequence analysis, this isolate was identified as Bacillus subtilis JSW-1; its further characterization showed that it could inhibit the growth of A. flavus with an inhibition ratio of 58.3% and could degrade AFB1 by 67.2% after incubation at 30 °C for 72 h. The aflatoxin B1-degrading activity of isolate JSW-1 was predominantly attributed to the cell-free supernatant and this activity was found to be heat stable but sensitive to proteinase K treatment, indicating that the extracellular proteins or enzymes are responsible for the AFB1 degradation. In addition, no degradation products of AFB1 could be detected by liquid chromatography-mass spectrometry (LC-MS) analysis, indicating that the parent AFB1 might be biotransformed to compounds with chemical properties different from that of AFB1.  相似文献   

9.
The contamination of peanuts with Aspergillus flavus and subsequent aflatoxins is considered to be one of the most serious safety problems in the world. Water activity (aw) and temperature are limiting factors for fungal growth and aflatoxins production during storage. To optimize the practical storage parameter, the effect of aw (0.85–0.99) and temperature (15–42 °C) on fungal growth, aflatoxin production and the expression of aflatoxin biosynthetic and regulatory genes in shelled peanuts was investigated. A. flavus grew at a lower rate when temperature ≤20 °C or aw ≤ 0.85. For the growth of A. flavus in shelled peanuts, the optimum conditions were aw was 0.98, and the optimum temperature was 37 °C. The maximum amount of AFB1 in peanuts was obtained at 28 °C and aw 0.96. Real-time analysis showed that 16 of 25 genes had highest expression levels at 28 °C under aw 0.92, while 9 genes had highest expression levels at 37 °C under aw 0.92. Compared with 37 °C, all aflatoxin biosynthetic pathway genes were down-regulated at 42 °C. All the pathway genes and laeA were up-expressed at aw of 0.96 under 28 °C, compared to aw 0.99. Furthermore, there was a good positive correlation between the ratio of aflS/aflR and AFB1 production. The expression of laeA was also positively correlated with AFB1 production while the expression of brlA was correlated with the A. flavus growth. The results of this study suggest that AFB1 production in peanut kernels can occur over a wider range of aw × temperatures levels compared to formula media and peanut media. Previous studies have showed that AFB1 could not be produced on formula media at 37 °C without the expression of most aflatoxin structural genes. But, in the un-autoclaved shelled peanuts, high concentration of AFB1 was produced at 37 °C with up-regulation of some aflatoxin biosynthetic genes. From a food safety point of view, the results can be used to optimize certain food technological processes and develop prevention strategies to control such carcinogenic natural metabolites in grains (such as peanuts, maize and rice) and derived products.  相似文献   

10.
Lippia rugosa essential oil was tested for its effectiveness against Aspergillus flavus on artificial growth media. The chemical composition of the oil was determined by gas chromatography–mass spectrometry (GC–MS). Geraniol (51.5%), nerol (18.6%) and geranial (10.4%) were the main components of Lippia oil. After 8 days of incubation on essential oil supplemented medium, mycelium growth of A. flavus was totally inhibited by 1000 mg l?1 of L. rugosa essential oil. The effect of essential oil on aflatoxin B1 synthesis was evaluated in SMKY broth. The medium supplemented with different essential oil concentrations, was inoculated with A. flavus mycelium and incubated at 25 °C. After 2, 4, 6 and 8 days, aflatoxin B1 (AFB1) was quantified in the supernatant using Enzyme Linked Immuno-Sorbent Assay (ELISA). Results showed that aflatoxin B1 synthesis was inhibited by 1000 mg l?1 of L. rugosa essential oil after 8 days of incubation. The effect of the EO on the H+-ATPase pumping membrane was also evaluated in the presence of several concentrations of oil (200–2000 mg l?1) by monitoring glucose-induced acidification of the external medium. L. rugosa essential oil at the concentration of 2000 mg l?1 completely inhibited the activity of this enzyme. These data suggest that the essential oil of L. rugosa is a fungicidal for A. flavus and its possible cellular target include the H+-ATPase.Results obtained in the present study indicate the possibility of exploiting Lippia rugosa essential oil in the fight against strains of A. flavus responsible for biodeterioration of stored foods products.  相似文献   

11.
A new strain of Bacillus pumilus, designated HY1, was isolated from Korean soybean sauce (kanjang). This classification was based on morphological, physiological, and chemotaxonomic features of the organism that identified it as a Gram-positive bacillus, and confirmed by 16S rDNA based phylogenetic analysis. Strain HY1 showed strong antifungal activity against the aflatoxin-producing fungi Aspergillus flavus and Aspergillus parasiticus, two common contaminants of fermented soybean foods. MALDI-TOF mass analysis revealed that the antifungal compound was similar to the known lipopeptide iturin. Iturin purified from strain HY1 had three isoforms with protonated masses of m/z 1,043.4, 1,057.4, and 1,071.4, and different structures in combination with Na+ ion using MALDI-TOF MS. Purified iturin from HY1 also exhibited antifungal activity against A. flavus and A. parasiticus.  相似文献   

12.
《Food Control》2007,18(7):817-820
The aim of this study was to prioritise disease and pest constraints in chilli by highlighting aflatoxin concentrations to assist local farmers in control. All samples contained aflatoxin B1 and high levels were obtained from all ground samples. A direct relationship was observed between aflatoxin B1 and aflatoxin B2 concentrations. There was no relation between aflatoxin and Aspergillus flavus detection. Chilli production in Pakistan may be heavily constrained by aflatoxin contamination. Simply removing A. flavus may be insufficient for control. Aflatoxins from chilli may be a threat to the health of populations and a constraint on development in Pakistan.  相似文献   

13.
In order to find out plants useful to controlling aflatoxins (AFs) production, the essential oils (EOs) from 12 medicinal plants prepared by hydrodistillation were studied with special reference to the inhibition of Aspergillus parasiticus growth and AFs production. The toxigenic fungus was cultured in presence of various oils in 6-well microplates using a microbioassay technique. The mycelial mass was estimated as an index of fungal growth, while the aflatoxins B1 (AFB1) and G1 (AFG1) were measured by high performance liquid chromatography (HPLC). Among plants tested, Thymus vulgari and Citrus aurantifolia were found to inhibit both A. parasiticus and AF production. The EOs from Mentha spicata L., Foeniculum miller, Azadirachta indica A. Juss, Conium maculatum and Artemisia dracunculus were only inhibited fungal growth, while Carum carvi L. effectively inhibited AF production without any obvious effect on fungal growth. The other plants including Ferula gummosa, Citrus sinensis, Mentha longifolia and Eucalyptus camaldulensis had no effect on A. parasiticus growth and AF production at all concentrations used. The IC50 values of T. vulgaris, C. aurantifolia and C. carvi for AF inhibition were reported as 93.5, 285.6, and 621.9 μg/ml for AFB1, while they were calculated as 11.7, 50.1, and 56.0 μg/ml for AFG1. These results indicate that the EOs of some medicinal plants may be considered as potential candidates to protect foods and feeds from toxigenic fungus growth and subsequent AF contamination.  相似文献   

14.
Atmospheric plasma provides the advantages of high microbial inactivation that can be performed under ambient conditions; therefore, it is regarded as a potential alternative to traditional food preservation methods. The present work presents the results of a critical study conducted on the efficiency of a non-thermal atmospheric pressure fluidized bed plasma (APFBP) system used for decontamination of maize. Maize grains that were artificially contaminated with Aspergillus flavus and Aspergillus parasiticus spores were treated in APFBP system for 1–5 min at two differently designed fluidized bed reactors with air and nitrogen. Results indicate maximum significant reductions of 5.48 and 5.20 log (cfu/g) in Aspergillus flavus and A. parasiticus after 5 min air plasma treatment. The native microbial flora of the maize grains decreased to more than 3 log after 3 min APFBP treatment, and no viable cells were counted. During the storage of plasma treated maize samples at 25 °C for 30 days, the Aspergillus spp. spores log reduction was maintained with no occurrence of re-growth. Overall, this study shows that plasma treatment has a fungicidal effect on A. flavus and A. parasiticus spores associated with alterations in spore surface morphology and loss of spore integrity. APFBP can inactivate aflatoxigenic spores on maize grains and could be optimized to improve the safety and quality of produce.  相似文献   

15.
Aspergillus carbonarius is the major ochratoxin A (OTA)-producing fungus that contaminates wine grapes. To investigate the effect of the initial amount of A. carbonarius on winemaking and ochratoxin A contamination, different conidial concentrations of A. carbonarius were manually added to the grape musts before fermentation. Sampling was carried out at different stages in alcoholic fermentation, including crushing, maceration, pressing and alcoholic fermentation. The levels of alcohols, soluble solids, and reducing sugars in the musts were analyzed before and during the whole procedure of alcoholic fermentation. Aspergillus spp. and other fungal contaminants increased rapidly after crushing, however most died at 48 h. OTA levels in the musts increased during the first 8–48 h and then decreased sharply in A. carbonarius inoculants (1 × 104 to 1 × 106 spores/g) in a spore concentration-dependent manner. Most OTA was retained in the pomaces fraction after the pressing operation. High amounts of A. carbonarius did not significantly affect yeast growth, sugar use, and alcoholic production during fermentation. In conclusion, high levels of contamination with A. carbonarius in the grape musts did not inhibit alcoholic fermentation, but caused high OTA residues in the wine produced.  相似文献   

16.
Aflatoxin B1 (AFB1), a mycotoxin mainly produced by some Aspergillus species, has been found in a wide range of agricultural products. To avoid the risk of AFB1 consumption, many agricultural commodities, foods and feeds should be analyzed and a rapid and non-instrumental method for the detection of AFB1 is needed. In this study, a rapid, inexpensive and user-friendly latex agglutination inhibition reaction test (LAIRT) for on site testing of AFB1 had been established. At first, carboxylated polystyrene latex particles (CPLP) were prepared by soap-free polymerization and sensitized with aflatoxin B1 oxime-BSA (AFB1O-BSA) for the detection of AFB1. In LAIRT, the agglutination reaction with AFB1O-BSA-sensitized CPLP and anti-AFB1 antiserum mixture was inhibited by 5 ng/mL AFB1 and the analysis time for 6 samples on one glass slide was less than 10 min. Subsequently, 10 rice and peanut samples were analyzed by LAIRT and ELISA, and the results showed that 1 rice sample and 2 peanut samples were positive and in agreement with those of ELISA. However, the results could be obtained more rapidly by LAIRT than ELISA. This easy and rapid LAIRT might be useful for screening AFB1 of agricultural commodities, foods and feeds in the field.  相似文献   

17.
Dried red chilies are among the world’s most consumed spices. From farm to fork, chilies go through cropping, harvest, drying, processing and storage. Chilies are susceptible to infection by aflatoxin producing fungi and subsequent contamination by aflatoxins at every stage. Aflatoxins are highly regulated, hepatotoxic carcinogens produced by fungi in Aspergillus section Flavi. The current study examined prevalence of aflatoxin B1 (AFB1) in chilies from markets across the United States (US) and Nigeria, and determined predisposition of chilies to aflatoxins post-harvest. Aflatoxin B1 was detected in 64% chilies from US markets (n = 169), and 93% of Nigerian chilies (n = 55) with a commercial lateral flow assay (Limit of Detection = 2 μg/kg). Two percent of US samples exceeded the aflatoxin regulatory limit of 20 μg/kg, while the highest concentration detected was 94.9 μg/kg. Aspergillus spp. could be recovered only from 40% of samples from the US, and aflatoxin levels did not correlate with quantities of Aspergillus section Flavi (Colony Forming Units g−1), suggesting fungi associated with chilies in US markets were killed during processing. Both average AFB1 concentrations and fungal quantities were significantly higher (p < 0.01) in Nigerian chilies. The most contaminated sample contained 156 μg/kg AFB1. Aflatoxin concentrations in Nigerian chilies increased as an exponential function of the quantities of Aspergillus section Flavi (r2 = 0.76). Results indicate that high rates of chili consumption may be associated with unacceptable aflatoxin exposure.  相似文献   

18.
《Food Control》2010,21(2):203-206
This study involved evaluation of physicochemical and microbiological changes in dried Pupuru (fermented, smoke dried cassava) balls under storage conditions simulating those currently used by the traditional processors. The aim was to understand the process of spoilage with a view to reducing the rate. pH ranged from 3 to 4, reducing significantly in cabinet-dried samples from 4.24 to 3.27 after 6 days of storage. Viable counts were in the range of 6–8 log cfu/g. Spoilage microorganisms included aerobic spore-forming and non-sporing bacteria as well as potentially toxigenic moulds like Aspergillus flavus and Penicillium species, which could constitute a health hazard to consumers.  相似文献   

19.
The aim of the study was to characterize the toxigenic moulds and to screen different mycotoxins in peppers (Piper nigrum L.) of Sri Lankan origin. Aspergillus flavus, Aspergillus parasiticus, Aspergillus niger and Penicillium spp. were found to be the most dominant fungi. Characterization of the moulds was carried out in A. flavus and parasiticus agar (AFPA) and malt extract agar (MEA) in 77 black pepper (BP) and 11 white pepper (WP) samples. In total, 73% of the BP and 64% of the WP samples were contaminated with A. flavus and/or A. parasiticus (AfAp). A BP sample with water activity (aw) 0.70 recorded the highest count of AfAp (4.3*104 CFU/g). Moreover, 75% of the BP samples exceeded the safe aw limit (0.65) set by the European Spice Association (ESA). The frequency of occurrence of A. niger in BP was 62% with counts up to 1.3*103 CFU/g. Penicillium spp. were found in 61% and 55% of the BP and WP samples, respectively. In BP 94% of the samples had a Penicillium contamination below 103 CFU/g. Other Aspergillus spp, found in peppers included, Aspergillus terrus, Aspergillus tamarii, Aspergillus candidus, Aspergillus penicilloides, Aspergillus sydowii and Aspergillus fumigatus. Mould counts in BP (102–104 CFU/g) were significantly higher than that of WP (<102 CFU/g). Apart from the occurrence of “classical mycotoxins” of spices, aflatoxins (<LOQ-18 μg/kg) and ochratoxin A (<LOQ-79 μg/kg), other toxins including fumonisin B1 (<LOQ-135 μg/kg), sterigmatocystin (<LOQ-49 μg/kg) and citrinin (<LOQ-112 μg/kg) were detected in peppers. In total, 63% of the BP samples were contaminated with at least one mycotoxin. Mycotoxin contamination in WP was significantly less compared to BP. The exposure to aflatoxins and ochratoxin A by consuming pepper remains harmless considering the existing pepper dietary intake data of the Sri Lankan population.  相似文献   

20.
The aim of this study was to investigate the occurrence of aflatoxin B1 (AFB1) and ochratoxin A (OTA) in different traditional meat products circulating on Croatian markets, produced by a large number of households situated in different Croatian regions. The study involved a total of 410 samples of traditional pork meat products in terms of hams (n = 105), dry fermented sausages (n = 208), bacon (n = 62) and cooked sausages (n = 35), collected over four years period (2011–2014). Mycotoxin concentrations were quantified and confirmed using validated immunoassay method (ELISA) and high performance liquid chromatography with fluorescence detection (HPLC-FLD), respectively. The maximal observed OTA level in the fermented sausages and hams was around 5 times (5.10 μg/kg) to 10 times (9.95 μg/kg) higher than the maximal recommended level (1 μg/kg) stipulated for pork products in some EU countries. AFB1 levels found in any given meat product analysed within this frame were not significantly higher (p > 0.05) than the applied method limit of detection. The results showed an occasional mycotoxin contamination of traditional meat products, especially that by OTA, pointing that to avoid such contamination meat and meat products on households should be produced and processed under standardised and well-controlled conditions.  相似文献   

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