Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 230
Filtrar
1.
J Agric Food Chem ; 72(23): 13360-13370, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38830379

RESUMO

This study reports a peptide design model for engineering fusion-expressed antimicrobial peptides (AMPs) with the AflR dinuclear zinc finger motif to improve the defense against aflatoxins and Aspergillus flavus. The study identified AflR, a Zn2Cys6-type sequence-specific DNA-binding protein, as a key player in the regulation of aflatoxin biosynthesis. By integrating the AflR motif into AMPs, we demonstrate that these novel fusion peptides significantly lower the minimum inhibitory concentrations (MICs) and reduce aflatoxin B1 and B2 levels, outperforming traditional AMPs. Comprehensive analysis, including bioinformatics and structural determination, elucidates the enhanced structure-function relationship underlying their efficacy. Furthermore, the study reveals the possibility that the fusion peptides have the potential to bind to the DNA binding sites of transcriptional regulators, binding DNA sites of key transcriptional regulators, thereby inhibiting genes critical for aflatoxin production. This research not only deepens our understanding of aflatoxin inhibition mechanisms but also presents a promising avenue for developing advanced antifungal agents, which are essential for global food safety and crop protection.


Assuntos
Aspergillus flavus , Dedos de Zinco , Aspergillus flavus/efeitos dos fármacos , Aspergillus flavus/genética , Aspergillus flavus/metabolismo , Aspergillus flavus/química , Peptídeos Antimicrobianos/química , Peptídeos Antimicrobianos/farmacologia , Peptídeos Antimicrobianos/genética , Peptídeos Antimicrobianos/metabolismo , Aflatoxinas/biossíntese , Aflatoxinas/química , Aflatoxinas/genética , Engenharia de Proteínas , Testes de Sensibilidade Microbiana , Antifúngicos/farmacologia , Antifúngicos/química , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/farmacologia
2.
Environ Monit Assess ; 194(9): 613, 2022 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35882690

RESUMO

The contamination of food commodities with mycotoxins could be a serious health threat to humans and animals. Therefore, identification, quantification and reduction of mycotoxins in food commodities, particularly of aflatoxins (AFs) and ochratoxin A (OTA) in grain foods, is essentially required to guarantee safe food. This study determined the levels of AFs and OTA in 135 maize grains samples belonging to eight salient maize varieties cultivated in Pakistan, and evaluated the usefulness of radiations and adsorbents to reduce their levels. High performance liquid chromatography (HPLC)-based method was validated for the determination of AFs and OTA in maize grains. The results showed that 69 and 61% samples were positive for AFs and OTA, respectively and 54 and 22% of the respective samples had AFs and OTA above the permissible limits set by Pakistan Standards and Quality Control Authority. The concentration of AFs, AFB1and OTA in grains ranged from 14.5 to 92.4, 1.02 to 2.46 and 1.41 to 53.9 µg kg-1, respectively. Among the varieties, Pearl had the highest level of total AFs and OTA, whereas YH-5427 had the highest AFB1 level. The lowest concentration of AFs and OTA was found in Malaka and 30Y87, respectively. The use of 15 kGy gamma irradiation for 24 h, sunlight-drying for 20 h and UV irradiation for 12 h almost completely degraded the mycotoxins. The microwave heating for 120 s resulted in 9-33% degradation of mycotoxins. Moreover, the treatment of grains' extract with activated charcoal (5% w/w) removed > 96% of total AFs and AFB1, and up to 43% of OTA. The use of bentonite at the same rate removed OTA, total AFs and AFB1 by 93, 73 and 92%, respectively. Thus, it is concluded that contamination of maize grains with mycotoxins was fairly high in the collected maize grain samples in Pakistan, and treatment with radiations and adsorbents can effectively reduce mycotoxins contamination level in maize grains.


Assuntos
Aflatoxinas , Micotoxinas , Ocratoxinas , Aflatoxinas/análise , Aflatoxinas/química , Animais , Monitoramento Ambiental , Contaminação de Alimentos/análise , Humanos , Micotoxinas/análise , Ocratoxinas/análise , Ocratoxinas/química , Paquistão , Zea mays/química
3.
Toxins (Basel) ; 14(2)2022 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-35202103

RESUMO

Aflatoxin contamination remains one of the most important threats to food safety and human health. Aflatoxins are mainly found in soil, decaying plant material and food storage systems and are particularly abundant during drought stress. Regulations suggest the disposal of aflatoxin-contaminated crops by incorporation into the soil for natural degradation. However, the fate and consequences of aflatoxin in soil and on soil organisms providing essential ecological services remain unclear and could potentially pose a risk to soil health and productivity. The protection of soil biodiversity and ecosystem services are essential for the success of the declared United Nations Decade on Ecosystem Restoration. The focus of this study was to investigate the toxicological consequences of aflatoxins to earthworms' survival, growth, reproduction and genotoxicity under different temperature and moisture conditions. Results indicated an insignificant effect of aflatoxin concentrations between 10 and 100 µg/kg on the survival, growth and reproduction but indicated a concentration-dependent increase in DNA damage at standard testing conditions. However, the interaction of the toxin with different environmental conditions, particularly low moisture, resulted in significantly reduced reproduction rates and increased DNA damage in earthworms.


Assuntos
Aflatoxinas/toxicidade , Oligoquetos/efeitos dos fármacos , Poluentes do Solo/toxicidade , Temperatura , Água , Aflatoxinas/química , Animais , Ensaio Cometa , Solo/química , Poluentes do Solo/química
4.
Toxins (Basel) ; 14(2)2022 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-35202136

RESUMO

Spent coffee grounds (SCGs), which constitute 75% of original coffee beans, represent an integral part of sustainability. Contamination by toxigenic fungi and their mycotoxins is a hazard that threatens food production. This investigation aimed to examine SCGs extract as antimycotic and anti-ochratoxigenic material. The SCGs were extracted in an eco-friendly way using isopropanol. Bioactive molecules of the extract were determined using the UPLC apparatus. The cytotoxicity on liver cancer cells (Hep-G2) showed moderate activity with selectivity compared with human healthy oral epithelial (OEC) cell lines but still lower than the positive control (Cisplatin). The antibacterial properties were examined against pathogenic strains, and the antifungal was examined against toxigenic fungi using two diffusion assays. Extract potency was investigated by two simulated models, a liquid medium and a food model. The results of the extract showed 15 phenolic acids and 8 flavonoids. Rosmarinic and syringic acids were the most abundant phenolic acids, while apigenin-7-glucoside, naringin, epicatechin, and catechin were the predominant flavonoids in the SCGs extract. The results reflected the degradation efficiency of the extract against the growth of Aspergillus strains. The SCGs recorded detoxification in liquid media for aflatoxins (AFs) and ochratoxin A (OCA). The incubation time of the extract within dough spiked with OCA was affected up to 2 h, where cooking was not affected. Therefore, SCGs in food products could be applied to reduce the mycotoxin contamination of raw materials to the acceptable regulated limits.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Café , Flavonoides/farmacologia , Fenóis/farmacologia , Resíduos , Aflatoxinas/química , Aflatoxinas/metabolismo , Antibacterianos/química , Antifúngicos/química , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Flavonoides/química , Contaminação de Alimentos/prevenção & controle , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Humanos , Ocratoxinas/química , Ocratoxinas/metabolismo , Fenóis/química
5.
Toxins (Basel) ; 14(1)2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-35051001

RESUMO

The aqueous extracts of leaves and shoots of Mentha arvensis were checked for their potential to biodegrade aflatoxin B1 and B2 (AFB1; 100 µg/L and AFB2; 50 µg/L) through in vitro assays. Overall, the results showed that leaf extract degrades aflatoxins more efficiently than the shoot extract. First, the pH, temperature and incubation time were optimized for maximum degradation by observing this activity at different temperatures between 25 and 60 °C, pH between 2 and 10 and incubation time from 3 to 72 h. In general, an increase in all these parameters significantly increased the percentage of biodegradation. In vitro trials on mature maize stock were performed under optimized conditions, i.e., pH 8, temperature 30 °C and an incubation period of 72 h. The leaf extract resulted in 75% and 80% biodegradation of AFB1 and AFB2, respectively. Whereas the shoot extract degraded both toxins up to 40-48%. The structural elucidation of degraded toxin products by LCMS/MS analysis showed seven degraded products of AFB1 and three of AFB2. MS/MS spectra showed that most of the products were formed by the loss of the methoxy group from the side chain of the benzene ring, the removal of the double bond in the terminal furan ring and the modification of the lactone group, indicating less toxicity compared to the parent compounds. The degraded products showed low toxicity against brine shrimps, confirming that M. arvensis leaf extract has significant potential to biodegrade aflatoxins.


Assuntos
Aflatoxina B1/metabolismo , Aflatoxinas/metabolismo , Mentha/química , Mentha/metabolismo , Extratos Vegetais/metabolismo , Folhas de Planta/metabolismo , Brotos de Planta/metabolismo , Aflatoxinas/química , Estrutura Molecular , Paquistão , Extratos Vegetais/química , Folhas de Planta/química , Brotos de Planta/química
6.
Artigo em Inglês | MEDLINE | ID: mdl-35093855

RESUMO

The potential of hair as matrix for assessing long-term exposure to mycotoxins remains scarcely explored. Therefore, this study aimed to develop and validate an analytical methodology for the simultaneous determination of aflatoxins, enniatins, beauvericin and T-2 toxin in human hair, based on a pretreatment stage prior to salt-assisted liquid-liquid extraction and followed by high performance liquid chromatography coupled to high resolution Q-TOF mass spectrometry for the first time. Washing with a non-ionic detergent was successfully applied, whereas enzymatic digestion with Pronase E was mandatory for releasing mycotoxins from the hair matrix. The methodology was validated according to Commission Decision 2002/657/EC, with limits of quantification ranging from 0.6 to 8.7 ng/g. The analysis of 10 samples showed at least one mycotoxin occurring in 67% of samples, including the carcinogenic aflatoxins. This is the first validated methodology for the quantification of multiple mycotoxins in human hair.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cabelo/química , Espectrometria de Massas em Tandem/métodos , Aflatoxinas/química , Humanos , Micotoxinas
7.
J Biomol Struct Dyn ; 40(10): 4328-4340, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-33308034

RESUMO

The spread of fungal growth causes enormous economic, agricultural, and health problems for humans, such as Aspergillus sp., which produce aflatoxins. Thus, the inhibition of aflatoxin production became a precious target. In this research, the thioesterase (TE) domain from Polyketide synthase enzyme was selected to employ the in silico docking, using AutoDock Vina, against 623 natural compounds from the South African natural compound database (SANCDB), to identify potential inhibitors that can selectively inhibit thioesterase domain. The top ten inhibitors components were pinocembrin, typhaphthalide, p-coumaroylputrescine, dilemmaone A, 9-angelylplatynecine, 2,4,6-octatrienal, 4,8-dichloro-3,7-dimethyl-, (2e,4z,6e)-, lilacinobiose, 1,3,7-octatriene, 5,6-dichloro-2-(dichloromethyl)-6-methyl-, [r*,s*-(e)]-(-)- (9ci), lilacinobiose, 1,3,7-octatriene, 5,6-dichloro-2-(dichloromethyl)-6-methyl-, [r*,s*-(e)]-(-)- (9ci), 1,3,7-octatriene, 1,5,6-trichloro-2-(dichloromethyl)-6-methyl-, [r*,s*-(z,e)] and 9-angelylhastanecine and that depending on the lowest binding energy, the best chemical interactions and the best drug-likeness. The results of those components gave successful inhibition with the thioesterase domain. So, they can be used for inhibition and controlling aflatoxin contamination of agriculture crop yields, specially, pinocembrin which gave promising results.Communicated by Ramaswamy H. Sarma.


Assuntos
Aflatoxinas , Aspergillus , Policetídeo Sintases , Aflatoxinas/química , Aspergillus/enzimologia , Policetídeo Sintases/química
8.
Int J Mol Sci ; 22(24)2021 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-34948120

RESUMO

According to the World Health Organization, the contamination of crops with aflatoxins poses a significant economic burden, estimated to affect 25% of global food crops. In the event that the contaminated food is processed, aflatoxins enter the general food supply and can cause serious diseases. Aflatoxins are distributed unevenly in food or feedstock, making eradicating them both a scientific and a technological challenge. Cooking, freezing, or pressurizing have little effect on aflatoxins. While chemical methods degrade toxins on the surface of contaminated food, the destruction inside entails a slow process. Physical techniques, such as irradiation with ultraviolet photons, pulses of extensive white radiation, and gaseous plasma, are promising; yet, the exact mechanisms concerning how these techniques degrade aflatoxins require further study. Correlations between the efficiency of such degradation and the processing parameters used by various authors are presented in this review. The lack of appropriate guidance while interpreting the observed results is a huge scientific challenge.


Assuntos
Aflatoxinas/química , Produtos Agrícolas , Descontaminação , Contaminação de Alimentos/prevenção & controle , Gases em Plasma/química , Humanos
9.
J Sep Sci ; 44(22): 4181-4189, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34558196

RESUMO

Mesoporous silica Santa Barbara-15 was functionalized by methacryloxypropyl trimethoxysilane. Taking this as the carrier material, a new mesoporous silica surface imprinted polymer was synthesized by using the C=C bond, functional monomer α-methacrylic acid, and crosslinker ethylene glycol dimethacrylate, which was used to extract aflatoxin from grain efficiently. It is different from the preparation of surface imprinted polymers which is physically wrapping carrier materials with polymer layers. The chemical grafting method makes the coating of the polymer layer more controllable. A new method for selective separation, enrichment, and determination of trace aflatoxin in grain was established by using the polymers as the filter of the solid-phase extraction column and high-performance liquid chromatography. The linear range of the method was 0.5-100 µg/kg, R2  = 0.9990-0.9993. The recovery of aflatoxin G2, G1, B2, and B1 was 98.9-119.7% and the relative standard deviation was 3.07-5.76%. By comparing the self-made column with the immunoaffinity column, it was found that the self-made column had better extraction performance for aflatoxins than the immunoaffinity column. It can be used for the analysis and detection of aflatoxins in cereal.


Assuntos
Aflatoxinas/análise , Grãos Integrais/química , Aflatoxinas/química , Cromatografia Líquida de Alta Pressão/métodos , Indústrias Extrativas e de Processamento/métodos , Impressão Molecular/métodos , Polímeros/química , Dióxido de Silício/química
10.
Molecules ; 26(12)2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34205651

RESUMO

High-pressure processing (HPP) has emerged over the last 2 decades as a good alternative to traditional thermal treatment for food safety and shelf-life extension, supplying foods with similar characteristics to those of fresh products. Currently, HPP has also been proposed as a useful tool to reduce food contaminants, such as pesticides and mycotoxins. The aim of the present study is to explore the effect of HPP technology at 600 MPa during 5 min at room temperature on alternariol (AOH) and aflatoxin B1 (AFB1) mycotoxins reduction in different juice models. The effect of HPP has also been compared with a thermal treatment performed at 90 °C during 21 s. For this, different juice models, orange juice/milk beverage, strawberry juice/milk beverage and grape juice, were prepared and spiked individually with AOH and AFB1 at a concentration of 100 µg/L. After HPP and thermal treatments, mycotoxins were extracted from treated samples and controls by dispersive liquid-liquid microextraction (DLLME) and determined by HPLC-MS/MS-IT. The results obtained revealed reduction percentages up to 24% for AFB1 and 37% for AOH. Comparing between different juice models, significant differences were observed for AFB1 residues in orange juice/milk versus strawberry juice/milk beverages after HPP treatment. Moreover, HPP resulted as more effective than thermal treatment, being an effective tool to incorporate to food industry in order to reach mycotoxins reductions.


Assuntos
Aflatoxinas/química , Bebidas/análise , Sucos de Frutas e Vegetais/análise , Frutas/química , Leite/química , Vitis/química , Animais , Cromatografia Líquida de Alta Pressão/métodos , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Lactonas/química , Microextração em Fase Líquida/métodos , Micotoxinas/química , Espectrometria de Massas em Tandem/métodos
11.
Artigo em Inglês | MEDLINE | ID: mdl-34187324

RESUMO

The present study describes a simple and rapid method for the determination of aflatoxins in almonds using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Aflatoxins were extracted using a modified QuEChERS method with little sample preparation, excluding the use of laborious purification procedures. Extracts were frozen overnight to separate the majority of lipids. The method was successfully validated for almonds. Linearity was demonstrated in the range 0.125-20 µg/kg. Limits of quantification (LOQ) ranged from 0.34 to 0.5 µg/kg. Matrix effect was not significant for the aflatoxins. Satisfactory recoveries were obtained at spike levels below 1 µg/kg and between 1 and 10 µg/kg. Relative standard deviations (RSDs) of repeatability and reproducibility were below 15%. The method was successfully tested with two proficiency tests in almond powder and peanut paste, with acceptable z-scores (-2 ≤ z ≤ 2). Only one of 11 local almond samples contained detectable aflatoxins, at concentrations below the maximum permitted level.


Assuntos
Aflatoxinas/isolamento & purificação , Análise de Alimentos , Contaminação de Alimentos/análise , Prunus dulcis/química , Aflatoxinas/química , Cromatografia Líquida , Espectrometria de Massas em Tandem
12.
Int J Mol Sci ; 22(9)2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-33926042

RESUMO

The control of the fungal contamination on crops is considered a priority by the sanitary authorities of an increasing number of countries, and this is also due to the fact that the geographic areas interested in mycotoxin outbreaks are widening. Among the different pre- and post-harvest strategies that may be applied to prevent fungal and/or aflatoxin contamination, fungicides still play a prominent role; however, despite of countless efforts, to date the problem of food and feed contamination remains unsolved, since the essential factors that affect aflatoxins production are various and hardly to handle as a whole. In this scenario, the exploitation of bioactive natural sources to obtain new agents presenting novel mechanisms of action may represent a successful strategy to minimize, at the same time, aflatoxin contamination and the use of toxic pesticides. The Aflatox® Project was aimed at the development of new-generation inhibitors of aflatoxigenic Aspergillus spp. proliferation and toxin production, through the modification of naturally occurring molecules: a panel of 177 compounds, belonging to the thiosemicarbazones class, have been synthesized and screened for their antifungal and anti-aflatoxigenic potential. The most effective compounds, selected as the best candidates as aflatoxin containment agents, were also evaluated in terms of cytotoxicity, genotoxicity and epi-genotoxicity to exclude potential harmful effect on the human health, the plants on which fungi grow and the whole ecosystem.


Assuntos
Aflatoxinas/química , Aflatoxinas/isolamento & purificação , Aspergillus flavus/química , Aflatoxinas/toxicidade , Antifúngicos/farmacologia , Aspergillus/metabolismo , Aspergillus/patogenicidade , Aspergillus flavus/isolamento & purificação , Aspergillus flavus/metabolismo , Aspergillus flavus/patogenicidade , Produtos Agrícolas/microbiologia , Ecossistema , Contaminação de Alimentos/prevenção & controle , Fungos/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Humanos , Micotoxinas/toxicidade , Tiossemicarbazonas/química
13.
Toxins (Basel) ; 13(1)2021 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-33435382

RESUMO

Mycotoxin contamination causes significant economic loss to food and feed industries and seriously threatens human health. Aflatoxins (AFs) are one of the most harmful mycotoxins, which are produced by Aspergillus flavus, Aspergillus parasiticus, and other fungi that are commonly found in the production and preservation of grain and feed. AFs can cause harm to animal and human health due to their toxic (carcinogenic, teratogenic, and mutagenic) effects. How to remove AF has become a major problem: biological methods cause no contamination, have high specificity, and work at high temperature, affording environmental protection. In the present research, microorganisms with detoxification effects researched in recent years are reviewed, the detoxification mechanism of microbes on AFs, the safety of degrading enzymes and reaction products formed in the degradation process, and the application of microorganisms as detoxification strategies for AFs were investigated. One of the main aims of the work is to provide a reliable reference strategy for biological detoxification of AFs.


Assuntos
Aflatoxinas/química , Aflatoxinas/metabolismo , Animais , Contaminação de Alimentos , Humanos , Lactobacillus/fisiologia , Saccharomyces/fisiologia
14.
J Sci Food Agric ; 101(9): 3707-3713, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33301189

RESUMO

BACKGROUND: Corn grains are commonly contaminated with mycotoxins and fungi. The purpose of this study was to evaluate the reduction of aflatoxins B1 , B2 , G1 , and G2 and the inhibition of Aspergillus niger in corn grains using ultrasound, ultraviolet (UV) radiation, electrolyzed water, and sodium bicarbonate. The determination of aflatoxins was performed by high-performance liquid chromatography with fluorescence detection and postcolumn derivatization, and analysis of A. niger was performed by evaluating mycelial growth in potato dextrose agar. The best treatment for reducing aflatoxins and inhibiting mycelial growth was evaluated in corn contaminated with A. niger. RESULTS: The results show a significant reduction in aflatoxins in the following order: sodium bicarbonate > ultrasound > UV > electrolyzed water for aflatoxins B1 , B2 , and G2 . For aflatoxin G1 , the order of reduction was sodium bicarbonate > ultrasound > electrolyzed water > UV, with maximum values between 70.50% and 87.03% reached with sodium bicarbonate; for the other treatments, the reduction was between 51.51% and 65.44%. Regarding the fungus, the order of inhibition in the control of mycelial growth was sodium bicarbonate > ultrasound > electrolyzed water > UV in corn grains, and inhibition of mycelial growth was obtained at a sodium bicarbonate concentration of 3.0 g L-1 . CONCLUSION: Sodium bicarbonate, electrolyzed water, ultrasound, and UV radiation inhibited the growth of A. niger on potato dextrose agar and reduced the contents of aflatoxins B1 , B2 , G1 , and G2 in vitro. Sodium bicarbonate showed an ability to inhibit mycelial growth in corn grains. © 2020 Society of Chemical Industry.


Assuntos
Aflatoxinas/química , Aspergillus niger/metabolismo , Conservação de Alimentos/métodos , Zea mays/química , Zea mays/microbiologia , Aflatoxinas/metabolismo , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/efeitos da radiação , Conservação de Alimentos/instrumentação , Sementes/química , Sementes/microbiologia , Bicarbonato de Sódio/farmacologia , Ultrassom , Raios Ultravioleta
15.
IET Nanobiotechnol ; 14(7): 623-627, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33010139

RESUMO

Agricultural commodities, particularly cereals can be contaminated with mycotoxins during the pre- and post-harvest stage. The main goal of this study was to evaluate the efficacy of magnetic zeolite nanocomposite (MZNC) as an adsorbent for the reduction of mycotoxins in barley flour. The MZNC is synthesised using an eco-friendly and efficient procedure and characterised by zeta potential, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The adsorbent amount that affects the adsorption capacity was optimised. Low amounts of the nanocomposite removed >99% of aflatoxins, 50% of ochratoxin A, 22% of zearalenone, and 1.8% of the deoxynivalenol from the contaminated sample and adsorption by MZNC was better than the natural zeolite; this phenomenon is related to the wide surface of nanocomposites. Results provide new insights into possible future research that could overcome the challenges of using nanotechnology to eliminate mycotoxins from agricultural products. It can be hoped that the presence of cheap and eco-friendly mycotoxin binders such as the MZNC that is synthesised and utilised in this research will help to produce secure food and feed products.


Assuntos
Aflatoxinas/química , Hordeum/efeitos dos fármacos , Micotoxinas/química , Nanotecnologia/métodos , Ocratoxinas/química , Tricotecenos/química , Zearalenona/química , Adsorção , Centaurea , Grão Comestível/química , Fenômenos Magnéticos , Microscopia Eletrônica de Varredura , Extratos Vegetais/química , Pós , Zeolitas
16.
Artigo em Inglês | MEDLINE | ID: mdl-33026964

RESUMO

Contamination of key staples with aflatoxins compromises the quality of food and feed, impedes trade, and negatively affects the health of consumers whereas acute exposure can be fatal. This study used the Contingent Valuation Method (CVM) on a sample of 480 farmers in counties prone to aflatoxin contamination to assess the willingness to pay (WTP) by farmers for Aflasafe KE01, a promising biological control product for the management of aflatoxin contamination of key staples in Kenya, compare its cost with that of a similar product in use in Nigeria, and determine factors likely to affect its adoption. Four hundred and eighty households from four counties identified as aflatoxin hotspots in Kenya were purposively selected and interviewed using a semi-structured questionnaire. The mean WTP per kilogram of Aflasafe KE01, using Contingent Valuation Method in the four counties ranged from Kenya Shillings (Ksh) 113 to 152/kg compared to a cost of Ksh. 130/kg, the price of a similar product, AflasafeTM, in Nigeria. Factors that positively influenced farmers' WTP included information from crop extension services and access to credit. To facilitate the adoption of Aflasafe KE01 or any other biocontrol product in Kenya and elsewhere, there is a need for increased education efforts through extension services to farmers about aflatoxins. Strategies to ensure that the biocontrol product is integrated into the credit scheme of the technological packages to farmers need to be considered.


Assuntos
Aflatoxinas/química , Contaminação de Alimentos/prevenção & controle , Agricultura , Produtos Biológicos/química , Análise Custo-Benefício , Fazendeiros , Humanos , Quênia , Nigéria , Exposição Ocupacional , Medição de Risco
17.
Food Chem Toxicol ; 146: 111830, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33127496

RESUMO

Recently, mycotoxins safety in Chinese post-fermented teas has attracted much attention because it is still controversial whether environmental fungi in the teas are able to produce aflatoxins. In this study, a rapid and selective analytical method based on immunoaffinity column (IAC) cleaning coupled with liquid chromatography-mass spectrometry (LC-MS) was developed to quantify four aflatoxins (B1, B2, G1 and G2) in post-fermented teas. Recoveries ranged from 80.8 to 92.2% with relative standard deviation less than 3%. The limits of detection and quantification were 0.109-0.348 µg kg-1 and 0.364-1.159 µg kg-1, respectively. Two out of 158 samples were positive for aflatoxins examination (occurrence rate 1.27%). The deterministic assessment for the maximal aflatoxins exposure under upper bound was 9.19 × 10-6 µg kg-1 day-1 from heavy exposure consumers (≥50 year age group), but the exposure was lower than the JECFA acceptable value of 1.0 ng kg-1 day-1 on liver risk. Probabilistic assessment showed that the upper bound 95th percentile carcinogenic risk value for the 318 consumers (Yunnan China and Ulan Bator Mongolia) was 1.75 × 10-7, and for heavy exposure consumers was 2.4 × 10-7, and the values equally below the acceptable carcinogenic risk level.


Assuntos
Aflatoxinas/química , Aflatoxinas/toxicidade , Chá/química , Adulto , China , Feminino , Fermentação , Contaminação de Alimentos , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco , Adulto Jovem
18.
Artigo em Inglês | MEDLINE | ID: mdl-32897822

RESUMO

ASPERGILLUS FLAVUS: is the main aflatoxin producer in food and feed and has wide ecological niches. Contamination of food products such as pistachio nuts and aflatoxin secretion directly affects food safety and international food product trades. Abilities of 13 yeast strains isolated from 200 soil and pistachio nut samples collected in Iranian orchards to reduce the growth of A. flavus as well as aflatoxin production were assessed in dual culture, volatile and non-volatile compounds tests. The growth of A. flavus was reduced by 32-60%, 13-31% and 40-61% in dual culture, volatile and non-volatile compounds, respectively, while aflatoxin B1 production was diminished by 90.6-98.3%. Based on these assays, five yeast strains were selected for co-inoculation experiments using soil, pistachio hulls and leaf. A significant reduction in colony-forming units (CFU) ranging from 23% to 110% (p < .05) was observed. Molecular, physiological and morphological identification revealed these were strains of Pichia kudriavzevii and Lachansea thermotolerans. Aflatoxin biocontrol with yeast strains possesses many advantages including the ease of commercial production and organic application which is an environmental approach. More investigation is required to understand the efficiency of selective strains to inhibit A. flavus and aflatoxin production as well as withstand predominant abiotic stress in pistachio orchards and mass production in field application.


Assuntos
Aflatoxinas/química , Antifúngicos/metabolismo , Aspergillus flavus/metabolismo , Agentes de Controle Biológico/metabolismo , Pistacia/metabolismo , Saccharomyces cerevisiae/metabolismo , Contaminação de Alimentos/prevenção & controle , Irã (Geográfico) , Nozes/microbiologia , Pichia/metabolismo , Patologia Vegetal , Saccharomyces cerevisiae/crescimento & desenvolvimento , Microbiologia do Solo , Compostos Orgânicos Voláteis/metabolismo
19.
Toxins (Basel) ; 12(9)2020 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-32825718

RESUMO

As a class of mycotoxins with regulatory and public health significance, aflatoxins (e.g., aflatoxin B1, B2, G1 and G2) have attracted unparalleled attention from government, academia and industry due to their chronic and acute toxicity. Aflatoxins are secondary metabolites of various Aspergillus species, which are ubiquitous in the environment and can grow on a variety of crops whereby accumulation is impacted by climate influences. Consumption of foods and feeds contaminated by aflatoxins are hazardous to human and animal health, hence the detection and quantification of aflatoxins in foods and feeds is a priority from the viewpoint of food safety. Since the first purification and identification of aflatoxins from feeds in the 1960s, there have been continuous efforts to develop sensitive and rapid methods for the determination of aflatoxins. This review aims to provide a comprehensive overview on advances in aflatoxins analysis and highlights the importance of sample pretreatments, homogenization and various cleanup strategies used in the determination of aflatoxins. The use of liquid-liquid extraction (LLE), supercritical fluid extraction (SFE), solid phase extraction (SPE) and immunoaffinity column clean-up (IAC) and dilute and shoot for enhancing extraction efficiency and clean-up are discussed. Furthermore, the analytical techniques such as gas chromatography (GC), liquid chromatography (LC), mass spectrometry (MS), capillary electrophoresis (CE) and thin-layer chromatography (TLC) are compared in terms of identification, quantitation and throughput. Lastly, with the emergence of new techniques, the review culminates with prospects of promising technologies for aflatoxin analysis in the foreseeable future.


Assuntos
Aflatoxinas/análise , Cromatografia com Fluido Supercrítico/métodos , Doenças Transmitidas por Alimentos/prevenção & controle , Extração Líquido-Líquido/métodos , Extração em Fase Sólida/métodos , Aflatoxinas/química , Aflatoxinas/toxicidade , Animais , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Cromatografia em Camada Fina/métodos , Doenças Transmitidas por Alimentos/diagnóstico , Doenças Transmitidas por Alimentos/etiologia , Cromatografia Gasosa-Espectrometria de Massas/métodos , Humanos
20.
Toxins (Basel) ; 12(7)2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32708252

RESUMO

Blueberry (BB) and cherry pomace were investigated as new biosorbents for aflatoxins (AFs) sequestration from buffered solutions, gastrointestinal fluids and model wine. Among the tested biosorbents, BB exhibited the maximum adsorption performance for AFs and hence was further selected for the optimization of experimental parameters like pH, dosage, time and initial concentration of AFs. Material characterizations via scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, N2 adsorption-desorption isothermal studies, thermogravimetric analysis (TGA) and X-ray photon spectroscopy (XPS) techniques revealed useful information about the texture and chemical composition of the biosorbents. The fitting of isothermal data with different models showed the model suitability trend as: Sips model > Langmuir model > Freundlich model, where the theoretical maximum adsorption capacity calculated from the Sips model was 4.6, 2.9, 2.7 and 2.4 mg/g for AFB1, AFB2, AFG1 and AFG2, respectively. Kinetics study revealed the fast AFs uptake by BB (50-90 min) while thermodynamics studies suggested the exothermic nature of the AFs adsorption from both, single as well as multi-toxin buffer systems, gastrointestinal fluids and model wine. Accrediting to the fast and efficient adsorption performance, green and facile fabrication approach and cost-effectiveness, the newly designed BB pomace can be counted as a promising contender for the sequestration of AFs and other organic pollutants.


Assuntos
Aflatoxinas/química , Mirtilos Azuis (Planta)/química , Fungos/metabolismo , Suco Gástrico/química , Resíduos Industriais , Secreções Intestinais/química , Modelos Químicos , Vinho/microbiologia , Absorção Fisico-Química , Soluções Tampão , Frutas , Concentração de Íons de Hidrogênio , Cinética , Porosidade , Propriedades de Superfície
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...