Toxigenic Aspergillus Flavus Research Articles

Competency of Clove and Cinnamon Essential Oil Fumigation against Toxigenic and Atoxigenic Aspergillus flavus Isolates

Aspergillus flavus is a frequent contaminant of maize grain. We isolated this fungus, determined the colony morphology and species (by internal transcribed spacer sequencing) and measured the aflatoxin content. The selected A. flavus fungi were placed into two groups, toxigenic and atoxigenic; both appeared similar morphologically, except that the atoxigenic group lacked sclerotia. An essential oil fumigation test with clove and cinnamon oils as antifungal products was performed on fungal conidial discs and fungal colonies in Petri plates. Cinnamon oil at 2.5 to 5.0 μL/plate markedly inhibited the mycelial growth from conidial discs of both strains, whereas clove oil showed less activity. The oils had different effects on fungal mycelia. The higher clove fumigation doses of 10.0 to 20.0 μL/plate controlled fungal growth, while cinnamon oil caused less inhibition. Compared with atoxigenic groups, toxigenic A. flavus responded stably. Within abnormal A. flavus hyphae, the essential oils degenerated the hyphal morphology, resulting in exfoliated flakes and shrinkage, which were related to fungal membrane injury and collapse of vacuoles and phialide. The treatments, especially those with cinnamon oil, increased the electroconductivity, which suggested a weak mycelium membrane structure. Moreover, the treatments with essential oils reduced the ergosterol content in mycelia and the aflatoxin accumulation in the culture broth. The fumigations with clove and cinnamon oils inhibited the development of both conidia and colonies of A. flavus in dose-dependent manners.

Antifungal activity of peracetic acid against toxigenic fungal contaminants of maize and barley at the postharvest stage

Contamination of maize and barley grain during storage by the toxigenic fungi Aspergillus flavus (A. flavus) and Penicillium Verrucosum (P. verrucosum) is both an economic and a public health problem, especially in less industrialized countries. Peracetic acid (PA) is a compound used for the disinfection of food and food contact surfaces. Unlike other disinfectants, it leaves no toxic residues and its decomposition products (CH3COOH, O2 and H2O) are environmentally friendly. In order to apply PA to preserve maize and barley grain during storage, first, the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) against both fungi were determined in a 96-well sterile microplates. Then, the antifungal activity of the volatile PA was determined by depositing it on filter paper and Hydroxyethylcellulose (HEC) gels, which were placed in airtight 1L flasks together with PDA and maize and barley grain inoculated with both fungi. The MFC in liquid medium of A. flavus and P. verrucosum was 93.8 and 187.5 mg/L respectively. However, PA doses of 300 and 200 mg/L on HEC gels were required in order to observe significant antifungal and antimycotoxigenic activity in maize and barley grain inoculated with these fungi.

Antifungal and antioxidant activity of plant based essential oils on Aspergillus flavus Link (Trichocomaceae) isolated from stored maize grains of Meghalaya

Essential oils from five medicinal aromatic plants viz. Gaultheria fragrantissima Wall, Artemisia nilagirica Clarke, Curcuma longa Linn, Zingiber officinale Roscoe and Litsea cubeba (Lour.) Pers. were evaluated for their efficacy as antifungal agents against the growth of toxigenic Aspergillus flavus Link isolated from stored maize of Meghalaya. Antifungal activity of essential oils was evaluated by determining the Minimal inhibition concentration (MIC) and Minimal fungicidal concentration (MFC). Among the five essential oils tested, Litsea cubeba essential oil showed high antifungal activity with complete mycelia growth inhibition at 0.8 µl/ml. Scanning Electron Microscopy of A. flavus exposed to oils showed hyphae and conidiophore damages. The essential oil exhibited antioxidant activity through DPPH (2,2-diphenyl-1-picrylhydrazyl) assay as IC50 value ranged between 0.59 and 14.44 µl/ml and are non-phytotoxic during seed germination experiments with maize seeds. Based on the antifungal, antioxidant and non-phytotoxic potential, the tested essential oils may be recommended as eco-friendly seed protectants.

Packaging fortified with Natamycin nanoparticles for hindering the growth of toxigenic Aspergillus flavus and aflatoxin production in Romy cheese.

Objective:This study assessed the effect of cellulose sheets fortified with Natamycin-loaded alginate nanoparticles on the growth of toxigenic Aspergillus flavus and aflatoxin production on the superficial layer of Egyptian Romy cheese after 12 weeks of maturation.Materials and Methods:Toxigenic A. flavus (GenBank accession No. MT645073) was inoculated into the outer surface of Egyptian Romy cheese (at 5 log CFU/gm) and wrapped with a cellulose sheet fortified with Natamycin-loaded alginate nanoparticles. Unwrapped control contaminated Romy wheels were made as well as non-contaminated wrapped cheese wheels for sensory evaluation. Romy cheese wheels were stored at a temperature similar to commercial methods for 12 weeks. Fungal counts were enumerated during this time, and enzyme-linked immune sorbent assay detected aflatoxin after the 4th week of maturation storage.Results:In cheese samples covered with cellulose sheets containing Natamycin-loaded alginate nanoparticles, the fungal count was reduced by 2 log approximately in contrast to control samples after the 2nd week of storage. However, within the 8th week of storage, the greatest significant reduction (p < 0.05) was seen where fungal growth was hindered entirely to the end of the ripening period. The mean values for taste, color, flavor, and overall acceptability were 4, 4.7, 4.09, and 4.3, respectively. Furthermore, in the treated samples, the total aflatoxin concentration was decreased by 78.6% relative to the untreated control one.Conclusion:Using cellulose sheets fortified with Natamycin-loaded alginate nanoparticles in Egyptian Romy cheese wrapping could be an effective way of controlling A. flavus and subsequent aflatoxin production without influencing the typical taste, color, flavor, and overall appearance of traditional Romy cheese.

In vitro antifungal activity of Desmodium intortum and D. uncinatum root extracts against growth of toxigenic Fusarium verticillioides and Aspergillus flavus

Maize grown under push-pull cropping system has been reported to contain lower concentrations of fumonisin and aflatoxin than maize monocrop. This study determined the inhibitory effect of desmodium root extracts on spore germination and radial growth of toxigenic Aspergillus flavus and Fusarium verticillioides. Aspergillus flavus and F. verticillioides were isolated from maize and soil and tested for ability to produce aflatoxin and fumonisin by inoculation on mycotoxin-free maize. Aflatoxin and fuminisin were detected and quantified by direct competitive ELISA. Desmodium roots were dried, ground to fine powder and extracted with methanol and dichloromethane and evaluated for anti-fungal activity by inhibition of spores of A. flavus and F. verticillioides potato dextrose agar (PDA) medium. Isolates of F. verticillioides produced up to 599,741 µg/kg fumonisin while isolates of A. flavus produced up to 199,184 µg/kg aflatoxin. Desmodium root extracts reduced germination of A. flavus spores and F. verticillioides by 9.6% and 43.8%, respectively and reduced their respective colony radial growth by 15% and 57%. The results suggested that desmodium roots contain chemical compounds that inhibit growth of A. flavus and F. verticillioides. This may explain the reduction in infection of maize with mycotoxin-producing fungi before harvest in push-pull cropping systems by reducing the pathogen inoculum in the soils. Determination of the active compounds in the root exudates is recommended

Growth Inhibition of Aflatoxigenic Molds and Biodegradation of Aflatoxin B1 by Certain Bacterial Isolates

AFLATOXIN B1 (AFB1) is mutagenic, carcinogenic, and harmful to humans and animals. Different physical and chemical methods have been proposed to reduce mycotoxins but few have been approved for practical application. This study investigated the possible use of certain bacterial species were isolated from different agricultural soils as biological control agents against the growth of toxigenic Aspergillus flavus and Aspergillus parasiticus isolated from sorghum and peanuts as well as biodegradation of aflatoxin B1 (AFB1). Out of these 30 bacterial isolates, 6 isolates showed that have antagonistic effects against the aflatoxigenic fungi but with varying efficiencies. The six different isolates were screened for their ability to degrade AFB1. Out of 6 isolates, one isolate showed high reduction activity of AFB1. Maximum antifungal activities were observed in one isolate was identified as Staphylococcus lentus. S. lentus completely prevented the A. flavus and A. parasiticus growth and completely degraded AFB1 in Liquid Culture. LC-MS/MS analysis revealed that S. lentus resulted in a 96.54% degradation of AFB1, but no products has been detected. In practical application, it was found that S. lentus at concentration of 10 and 25mL kg-1 were completely prevented the growth of A. flavus and A. parasiticus in sorghum and peanuts, respectively, consequently no aflatoxin were produced. According to our information, this is the first study to prove that Staphylococcus lentus has the capability to inhibit the growth of Aspergillus flavus and Aspergillus parasiticus by 100% and degrading AFB1 by 96%.

Isolation of toxigenic Aspergillus flavus and evaluation of aflatoxins in “Burukutu”, sorghum fermented beverage sold in Akure, Nigeria

The possible health threat accompanied with the ingestion of ‘Burukutu’, an alcoholic beverage made from fungal contaminated cereals grains calls for regular inspection. The study aimed at the isolation of toxigenic Aspergillus flavus and quantification of aflatoxins in‘Burukutu’ sold in Akure, Nigeria. The fungi associated with the samples were isolated and counted using standard microbiological methods. Aflatoxins were extracted from 64 samples using different solvents and analyzed with the aid of High Performance Thin-Layer Chromatography (HPTLC). The aflatoxins in the samples applied on pre-heated HPTLC plates were estimated under fluorescent UV light. Cooked fermented milled malted grains ‘Burukutu’ (CFMMG) had the highest fungal counts of 6.8×102 and 2.9×102 cfu/ml at 24 and 48 h of incubation respectively. The fungal isolates identified from the samples were: Aspergillus flavus, Fusarium solani, Rhizopusstolonifer, A. fumigatus, A. niger, Penicillumitalicum, Saccharomyces cerevisae and Candida krusei. All the analyzed samples showed varied quantity of aflatoxin concentrations. The overall quantification of aflatoxins G1, G2, B1 and B2 revealed significant reduction in end products ‘Burukutu’ when compared with the substrates from which it was made. Different general fungi associated with ‘Burukutu’ were identified. There was also a decline in the level of aflatoxins in ‘Burukutu’ which was a product of natural fermentation

Rhizopus oligosporus Activity in Crude Extract and Powder Form to Reduce Aspergillus flavus and Aflatoxin Contamination in Corn

Rhizopus oligosporus (RO) in isolate culture was known to reduce contamination toxigenic mold Aspergillus flavus (AF) and aflatoxin B1 in chicken feed. Application in culture form was not effective. The aim of this research was to evaluate RO activities in extract and inoculum form to reduce contamination of AF and aflatoxin B1 in corn. RO was harvested from agar plate, blended, added with water (ratio 1:1 (w/v)) and centrifuged. Supernatant was filtered using Whatman 41. Inoculum was made by inoculation RO in soy powder and incubated at 28oC for 5 days. Inoculum was dried at 40oC for 24-28 hours. Assay was conducted by addition extract or inoculum to corn. Extract and corn ratio were 1:1 (v/w), while inoculum doses were 5, 25, 50, 1000 dan 200 g/kg corn. Assay for aflatoxin B1 was done using kit ELISA aflatoxin. The result of this research showed that extract was able to reduce AF contamination up to 1 log 10, while the less concentration of inoculum which able to inhibit AF up to 6 log 10 was 100 g/kg corn. Extract RO 125 and 250 mL/kg corn was able to reduce aflatoxin contamination by 93.69 % and 85.84 %. Inoculum at dose 5 and 100 g/kg corn was able to reduce aflatoxin 57.58% and 85%. Based on the result, it could be concluded that RO in extract or inoculum form was able to reduce contamination of AF and aflatoxin B1 in corn. Rhizopus as inoculum was easier to be applied than in extract form.

Fabrication, characterization and practical efficacy of Myristica fragrans essential oil nanoemulsion delivery system against postharvest biodeterioration.

The present study deals with encapsulation of Myristica fragrans essential oil (MFEO) into chitosan nano-matrix, their characterization and assessment of antimicrobial activity, aflatoxin inhibitory potential, safety profiling and in situ efficacy in stored rice as environment friendly effective preservative to control the postharvest losses of food commodities under storage. Surface morphology of MFEO-chitosan nanoemulsion as well as encapsulation of MFEO was confirmed through SEM, FTIR and XRD analysis. In vitro release characteristics with biphasic burst explained controlled volatilization from nanoencapsulated MFEO. Unencapsulated MFEO exhibited fungitoxicity against 15 food borne molds and inhibited aflatoxin B1 secretion by toxigenic Aspergillus flavus LHP R14 strain. In contrast, nanoencapsulated MFEO showed better fungitoxicity and inhibitory effect on aflatoxin biosynthesis at lower doses. In situ efficacy of unencapsulated and nanoencapsulated MFEO on stored rice seeds exhibited effective protection against fungal infestation, aflatoxin B1 contamination, and lipid peroxidation. Both the unencapsulated and nanoencapsulated MFEO did not affect the germination of stored rice seeds confirming non-phytotoxic nature. In addition, negligible mammalian toxicity of unencapsulated MFEO (LD50=14,289.32μL/kg body weight) and MFEO loaded chitosan nanoemulsion (LD50=9231.89μL/kg body weight) as revealed through favorable safety profile recommend the industrial significance of nanoencapsulated MFEO as an effective green alternative to environmentally hazardous synthetic pesticides for protection of food commodities during storage.

Activity and Anti-Aflatoxigenic Effect of Indigenously Characterized Probiotic Lactobacilli against Aspergillus flavus-A Common Poultry Feed Contaminant.

Simple SummaryMycotoxicosis in poultry has been seriously damaging the poultry production in Pakistan, resulting in economic losses to the country. The present study may act as a preliminary step for exploring the effect of indigenously characterized potential probiotic lactobacilli on aflatoxin production by Aspergillus flavus. The present study explored anti-fungal Lactobacillus strains. Further investigations revealed their in vitro aflatoxin binding and anti-aflatoxigenic capabilities. These findings demonstrated L. gallinarum PL 149 to be an effective binder of aflatoxin B1 which may be used as a biocontrol agent against A. flavus and aflatoxin B1 production. It may be further employed for aflatoxin binding in poultry gut after in vivo evaluations.Aflatoxin contamination in human food and animal feed is a threat to public safety. Aflatoxin B1 (AFB1) can be especially damaging to poultry production and consequently economic development of Pakistan. The present study assessed the in vitro binding of AFB1 by indigenously characterized probiotic lactobacilli. Six isolates (Lactobacillus gallinarum PDP 10, Lactobacillus reuetri FYP 38, Lactobacillus fermentum PDP 24, Lactobacillus gallinarum PL 53, Lactobacillus paracasei PL 120, and Lactobacillus gallinarum PL 149) were tested for activity against toxigenic Aspergillus flavus W-7.1 (AFB1 producer) by well diffusion assay. Only three isolates (PL 53, PL 120, and PL 149) had activity against A. flavus W-7.1. The ameliorative effect of these probiotic isolates on AFB1 production was determined by co-culturing fungus with lactobacilli for 12 days, followed by aflatoxin quantification by high-performance liquid chromatography. In vitro AFB1 binding capacities of lactobacilli were determined by their incubation with a standard amount of AFB1 in phosphate buffer saline at 37 °C for 2 h. AFB1 binding capacities of isolates ranged from 28–65%. Four isolates (PDP 10, PDP 24, PL 120, and PL 149) also ceased aflatoxin production completely, whereas PL 53 showed 55% reduction in AFB1 production as compared to control. The present study demonstrated Lactobacillus gallinarum PL 149 to be an effective candidate AFB1 binding agent against Aspergillus flavus. These findings further support the binding ability of lactic acid bacteria for dietary contaminants.

HPLC quantitation of aflatoxin B1 from fungal mycelium culture

Aflatoxins are mycotoxins that contaminate agricultural products when infected by toxigenic Aspergillus flavus. Methods for quantifying aflatoxin from culture using chromatography are available but are not optimized for population studies. We provide details of a method for preparation and quantitation of aflatoxin B1 from fungal cultures that satisfy those needs.

Influence of Using Different Drying Technique on the Level of Toxigenic Aspergillus flavus in Maize (Zea mays) Seeds

Influence of Using Different Drying Technique on the Level of Toxigenic Aspergillus flavus in Maize (Zea mays) Seeds

Antifungal and aflatoxin-reducing activity of extracellular compounds produced by soil Bacillus strains with potential application in agriculture

Toxigenic Aspergillus flavus and A. parasiticus fungal strains can contaminate a wide variety of food crops with the subsequent production of aflatoxins (AFs) resulting in severe economic losses and public health issues. Biological control is a promising approach to manage AFs contamination in pre- and post-harvested crops. In the present study, the effect of soil-borne Bacillus spp. strains on aflatoxigenic A. parasiticus growth and AFs production was evaluated and the culture supernatant of the most effective strain was evaluated for the presence of antifungal lipopeptides. Six Bacillus spp. strains were able to reduce A. parasiticus growth rate significantly (p < 0.05). Bacillus spp. RC1A was able to inhibit fungal growth almost completely, reducing growth rate to 0.16 mm/h and increasing Lag phase duration (31.72 h) (p < 0.0001). RC1A could also reduce AFB1 concentration produced by A. parasiticus (p < 0.0001). Organic solvent extraction and chromatographic analysis of RC1A culture supernatant showed the presence of bands corresponding to three of the main groups of lipopeptides (surfactin, iturin A and fengycin) at the expected retention factor (Rf) values; they were also confirmed by MALDI-MS analysis. These fractions were able to inhibit A. parasiticus growth and AFB1 production to non-detectable levels when tested separately in liquid culture media. The further study of the antifungal compounds produced by these strains will determine their potential use to manage AFs contamination in crops and feeds.

Temporal Effects on Internal Fluorescence Emissions Associated with Aflatoxin Contamination from Corn Kernel Cross-Sections Inoculated with Toxigenic and Atoxigenic Aspergillus flavus.

Non-invasive, easy to use and cost-effective technology offers a valuable alternative for rapid detection of carcinogenic fungal metabolites, namely aflatoxins, in commodities. One relatively recent development in this area is the use of spectral technology. Fluorescence hyperspectral imaging, in particular, offers a potential rapid and non-invasive method for detecting the presence of aflatoxins in maize infected with the toxigenic fungus Aspergillus flavus. Earlier studies have shown that whole maize kernels contaminated with aflatoxins exhibit different spectral signatures from uncontaminated kernels based on the external fluorescence emission of the whole kernels. Here, the effect of time on the internal fluorescence spectral emissions from cross-sections of kernels infected with toxigenic and atoxigenic A. flavus, were examined in order to elucidate the interaction between the fluorescence signals emitted by some aflatoxin contaminated maize kernels and the fungal invasion resulting in the production of aflatoxins. First, the difference in internal fluorescence emissions between cross-sections of kernels incubated in toxigenic and atoxigenic inoculum was assessed. Kernels were inoculated with each strain for 5, 7, and 9 days before cross-sectioning and imaging. There were 270 kernels (540 halves) imaged, including controls. Second, in a different set of kernels (15 kernels/group; 135 total), the germ of each kernel was separated from the endosperm to determine the major areas of aflatoxin accumulation and progression over nine growth days. Kernels were inoculated with toxigenic and atoxigenic fungal strains for 5, 7, and 9 days before the endosperm and germ were separated, followed by fluorescence hyperspectral imaging and chemical aflatoxin determination. A marked difference in fluorescence intensity was shown between the toxigenic and atoxigenic strains on day nine post-inoculation, which may be a useful indicator of the location of aflatoxin contamination. This finding suggests that both, the fluorescence peak shift and intensity as well as timing, may be essential in distinguishing toxigenic and atoxigenic fungi based on spectral features. Results also reveal a possible preferential difference in the internal colonization of maize kernels between the toxigenic and atoxigenic strains of A. flavus suggesting a potential window for differentiating the strains based on fluorescence spectra at specific time points.

Influence of Different Moisture Contents and Temperature on Growth and Production of Aflatoxin B1 by a Toxigenic Aspergillus flavus Isolate in Wheat Flour

Influence of Different Moisture Contents and Temperature on Growth and Production of Aflatoxin B1 by a Toxigenic Aspergillus flavus Isolate in Wheat Flour

Grain Chemical Composition as Affected by Genetic Backgrounds and Toxigenic Aspergillus flavus Inoculation in Corn Hybrids

Mycotoxins are toxic secondary metabolites commonly found in corn and known to cause health issues to human and animals. Information on the relationship between corn grain inoculated with mycotoxins and grain nutrients (protein, oil, fatty acids, sugars, and amino acids) in corn hybrids, especially stacked-gene hybrids is very limited. The objective of this study was to investigate the nutritional advantage of stacked-gene hybrids (Stgene) over non-genetically modified organisms (non-GMO) corn or glyphosate-resistant corn (RR). The experiment was conducted in two locations (clay and sandy soils) in 2011, irrigated, and inoculated with toxigenic Aspergillus flavus using four hybrids of stacked-gene, four of RR, and two non-GMO (conventional). Non-inoculated plots were used as control. The results showed that stacked-gene hybrids had no observable nutritional advantage over RR or non-GMO as all hybrid classes accumulated adequate nutrients in their grains; this effect could be due to adequate concentrations of nutrients in the soil. Higher levels of grain protein, carbohydrates (glucose, reducing sugars, and starch), oleic acid, total amino acids, and some minerals were observed under inoculated conditions in clay and sandy soils indicated a possible osmotic adjustment role of these compounds as stress indicators and osmoprotectants under inoculated conditions. Grain nutrients in clay soil were higher than those in sandy soils; nutrient differences could be due to sandy soil possibly suffering drier conditions, especially inoculated soil, reducing nutrient uptake and nutrients mobility to the grain. This study provides advanced knowledge on the relationship between grain nutrients and mycotoxins in corn hybrids. It is also useful to the corn breeders to understand the responses of grain nutrients to fungal diseases in corn hybrids.

Isolation of Antifungal Lactic Acid Bacteria (LAB) from "Kunu" against Toxigenic Aspergillus flavus.

The antifungal activity of isolated lactic acid bacteria (LAB) from a locally fermented cereal, “Kunu”, was tested against toxigenic Aspergillus flavus. The liquid refreshment, “Kunu”, was prepared under hygienic condition using millet, sorghum, and the combination of the two grains. The antifungal potential of isolated LAB against toxigenic A. flavus was carried out using both in vitro and in vivo antifungal assays. The LAB count from prepared “Kunu” ranged from 2.80 ×104 CFU/mL to 4.10×104 CFU/mL and Lactobacillus plantarum, Lactobacillus delbrueckii, Lactobacillus fermentum, Pediococcus acidilactici, and Leuconostoc mesenteroides were the isolated bacteria. Inhibitory zones exhibited by LAB against toxigenic A. flavus ranged from 5.0 mm to 20.0 mm. The albino mice infected with toxigenic A. flavus showed sluggishness, decrease in body weight, distortion of hair, and presence of blood in their stool, while those treated with LAB after infection were recovered and active like those in control groups. Except for the white blood cell that was increased in the infected mice as 6.73 mm3, the packed cell volume, hemoglobin, and red blood cell in infected animals were significantly reduced (P<0.05) to 29.28%, 10.06%, and 4.28%, respectively, when compared to the treated mice with LAB and control groups. The antifungal activity of LAB against toxigenic A. flavus can be attributed to the antimicrobial metabolites. These metabolites can be extracted and used as biopreservatives in food products to substitute the use of chemical preservatives that is not appealing to consumers due to several side effects.

Low-cost humic acid-bonded silica as an effective solid-phase extraction sorbent for convenient determination of aflatoxins in edible oils

Aflatoxins (AFs) are highly toxic, mutagenic, carcinogenic, and teratogenic secondary metabolites produced by the toxigenic fungi Aspergillus flavus and Aspergillus parasiticus. AFs tend to contaminate a wide range of foods which is a serious and recurring food safety problem worldwide. Currently, immunoaffinity chromatography (IAC) has become the most conventional sample clean-up method for determining AFs in foodstuffs. However, IAC method is limited in the large-scale food analysis because it requires the use of expensive disposable cartridges and the IA procedure is time-consuming. Herein, to achieve the cost-effective determination of AFs in edible oils, we developed a promising solid-phase extraction (SPE) method based on commercially available humic acid-bonded silica (HAS) sorbent, followed by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) analysis. In HAS-SPE, AFs can be captured by the HAS sorbent with both hydrophobic and hydrophilic interactions, whereas the oil matrix was captured only with the hydrophobic interactions. The oil matrix can be sufficiently washed off with isopropanol, while the AFs were still retained on the SPE packing, thus achieving selective extraction of AFs and clean-up of oil matrices. Under the optimal conditions of HAS-SPE, satisfactory recoveries ranging from 82% to 106% for four AFs (B1, B2, G1, and G2) were achieved in various oil matrices, containing blended oil, tea oil, rapeseed oil, peanut oil, sunflower seed oil, corn oil, blended olive oil, rice oil, soybean oil, and sesame oil. Only minor matrix effects ranging from 99% to 105% for four AFs were observed. Moreover, the LODs of AFs between 0.012 and 0.035 μg/kg completely meet the regulatory levels fixed by the EU, China or other countries. The methodology was further validated for assaying the naturally contaminated peanut oils, and consistent results between the HAS-SPE and the referenced IAC were obtained. In addition, HAS-SPE can directly treat diluted oil sample without liquid-liquid extraction and is automatable, thus making it simple and convenient for the large-scale determination of AFs in edible oils. Using this method, we successfully detected four AFs in the naturally contaminated peanut oils, which is, to the best of our knowledge, the first report about the determination of AFs in edible oils using HA-based SPE.

Occurrence of toxigenic Aspergillus flavus in commercial Bulgur wheat

Aflatoxins are mutagenic, carcinogenic, and teratogenic mycotoxins. The objective of this work was to study the presence of aflatoxigenic Aspergillus in commercial Bulgur wheat in the city of Maringá, Paraná, Brazil. Thirty samples of commercial Bulgur wheat, acquired in the period of August 2011 to January 2012, were evaluated. The enumeration analysis showed that samples had up to 273.3 CFU of molds and 133.3 CFU of aflatoxigenic Aspergillus per gram of wheat. Forty-two monosporic isolates were obtained and identified as Aspergillus flavus. The isolates were analyzed regarding their aflatoxigenic potential by culture in coconut milk agar; hydroxide vapor exposure; chromatography; and polymerase chain reaction (PCR) targeting genes that code enzymes of the aflatoxins synthesis pathway. Some of the isolates were confirmed to be aflatoxin producers and several of them presented a genetic profile of aflatoxin synthesis. The obtained results demonstrated that Bulgur wheat A. flavus contamination is concerning.

Influence of Different Processing Methods on Aflatoxin Level in &amp;lt;i&amp;gt;Ogi&amp;lt;/i&amp;gt; Slurry Produced from Millet (&amp;lt;i&amp;gt;Pennisetum typhoideum&amp;lt;/i&amp;gt;)

The global shortage of cereal foods arising from improper processing and preservation methods adopted in some of our industries could be the sources of contamination of various food products which could lead to devastating health disorder. From this study, millet grains were subjected to different processing methods such as fermentation, alkaline boiling, oven drying and sun drying. The microorganisms associated with the processed samples were isolated and identified using standard microbiological and biochemical methods. The extraction, detection and quantification of aflatoxin from ogi slurry were quantified using thin layer chromatography. The sample fermented with ethanol and water showed higher fungal count 37.33cfu/ml while the sample fermented in sodium hypochloride shown no growth of Aspergillus flavus with fermentation time at initial inoculation. The milled fermented oven dry sample showed higher colony counts 14.50 cfu/g when compared to milled sun-dry and alkaline boiling fermented samples. The aflatoxin level of the ogi slurry ranged from 0.00ppb to 0.02ppb. Samples fermented with water and ethanol showed high effect in removal of aflatoxin B and G produced by toxigenic Aspergillus flavus while the alkaline boiling showed less effect on aflatoxin B1 and B2. Aflatoxin G1 and G2 were completely removed/destroyed from the sample fermented with ordinary water with aflatoxin level 0.00ppb. The sample subjected to oven dry and sun-dry showed complete removal/reduction in aflatoxin B1 and G1. The reduction in aflatoxin level of ogi slurry produced from millet using different processing methods showed its permissible level below the standard as recommended by National Agency for Food Drug Administration and Control (NAFDAC) and European Union which could be promising prior to this methods in controlling the level of contaminant in our food products for human use.