Quantitation of aflatoxins in walnut kernels by high-performance liquid chromatography with fluorescence detection

A total of 85 walnut samples collected between October 2012 and April 2013 in different provinces of Turkey were analysed for the presence of aflatoxins (AFs). The method involved methanol–water extraction, clean-up with immunoaffinity columns and a sensitive high-performance liquid chromatography coupled with fluorescence detection after post-column derivatisation. The method was validated for selectivity, linearity, trueness, precision, limit of detection and limit of quantification (LOQ), which met the performance criteria as set by EC regulation No. 401/2006. LOQs were 0.07, 0.04, 0.09 and 0.05 µg kg^–1 for AFB₁, AFB₂, AFG₁ and AFG₂, respectively. AFs were present in 9.4% of walnut samples (8/85) at total AFs levels ranging from 0.09 to 15.4 µg kg^–1. Only one of eight walnut samples exceeded the European Union limit of 2 and 4 µg kg^–1 for AFB₁ and total AFs, respectively.     

Distribution of fungi and aflatoxins in a stored peanut variety

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

Comparison of dry matter losses and aflatoxin B1 contamination of paddy and brown rice stored naturally or after inoculation with Aspergillus flavus at different environmental conditions

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

Aflatoxins in animal feed in Iran

One hundred and forty-six samples of animal feed (barley, n = 60; wheat bran, n = 22; wheat dry pulp, n = 29; and canola meal, n = 35) were collected in 2011 from Mashhad (Khorasan, Iran). Aflatoxins (AFs) were determined in these samples after immunoaffinity column clean-up by high-performance liquid chromatography (HPLC) with fluorescence detection. Aflatoxin B₁ (AFB₁) contamination was found in 28 samples: in five of the barley samples (8.3%) at a mean level of 0.48 µg·kg^?1, in two wheat bran samples (9.0%) at a mean level of 0.88 µg·kg^?1, in 10 wheat dry pulp samples (34.5%) at a mean level of 0.30 µg·kg^?1 and in 11 canola meal samples (31.4%) at a mean level of 0.92 µg·kg^?1. AFB₁ levels were below the maximum levels of Iran regulations (5 µg·kg^?1) and the EU maximum limit (5 µg·kg^?1).     

Effects of coating pistachio kernels with mixtures of whey protein and selected herbal plant extracts on growth inhibition of Aspergillus flavus and prevention of aflatoxin during storage

Whey protein concentrate (WPC) mixed with various concentrations of Shirazi thyme (ST), sage, and cumin seed (CS) extracts separately. Then pistachio kernels (PK) contaminated with Aspergillus flavus (Af) were coated with each extract and the Af mycelium and generated aflatoxins measured after 3, 5, and 7-days at 20°C. The ST, sage, and CS had two major antioxidants of thymol (~27%) and carvacrol (~41%), α-thujone (~28%) and camphor (~14%), and cumin-aldehyde (~21%) and safranal (~20%), respectively. While the Af mycelium diameter on PK without extract became >90 mm within 3 days, it was shrunk after 7 days when the WPC-coated PK had 4,000 ppm ST extract. When ST concentrations increased in WPC-coated PK linearly, the Af growth and aflatoxins production decreased logarithmically. No aflatoxins (B₁, B₂, G₁, and G₂) detected in PK after 9 days when the extract concentrations of ST, sage, and CS in WPC reached, respectively to 5,000, 4,500, and 6,500 ppm. Sage extract had significantly (p < .01) the highest TPC (lowest IC₅₀) and preventing power for aflatoxin generation in comparison with ST and CS extracts. The PK will be safe and healthy if the extract concentration of sage, ST, and CS exceed 950, 1,400, and 1,700 mg/kg, respectively.     

Aflatoxin in household maize for human consumption in Kenya,East Africa

ABSTRACT

The objective of this study is to determine the occurrence and level of aflatoxins (AFs) contamination in freshly harvested maize for human consumption in rural Kenya. Maize kernels and freshly milled maize flour (n = 338) were collected from households in Siaya and Makueni counties. While both counties are representatives of different environmental and climate conditions, Makueni County is the area with reported outbreaks of aflatoxicosis. Samples were analysed for AFB₁, AFB₂, AFG₁, and AFG₂ using Ultra High-Pressure Liquid Chromatography with Fluorescence detection. AFs were detected in 100% of the samples with the range of 2.14–411 µg/kg. The geometric mean of total AFs in all samples from Makueni County is 62.5 μg/kg with 95% CI: 53.7, 71.4 while in Siaya County is 52.8 μg/kg with 95% CI: 44.0, 61.7. This study showed that AFs contamination is prevalent in maize-based foods in the region.     

Photodegradation of Aflatoxin B<Subscript>1</Subscript> in peanut oil

A photodegradation study of aflatoxin B₁ (AFB₁) in peanut oil was performed under UV irradiation at different AFB₁ initial concentrations and UV irradiation intensities. The UV intensity and the irradiation duration on the AFB₁ photodegradation ratio is more effective, when compared with AFB₁ initial concentration, and AFB₁ with initial concentration of 2 mg/kg can be degraded thoroughly within 30 min under the intensity of 800 μw/cm². The photodegradation of AFB₁ between the selected ranges of concentrations was proved to follow first-order reaction kinetics well (R ² ≥ 0.99). The Ames test, employing Salmonella typhimurium tester strains TA98 and TA100, was employed to evaluate the residual toxicity of the AFB₁ subproducts in peanut oil, and the results indicated that the mutagenic activity of UV-treated samples (800 μw/cm² × 30 min) was completely lost compared with that of untreated samples, providing clues to the assessment of safety issues of UV method applied in AFB₁ decontamination.     

Aflatoxins in composite spices collected from local markets of Karachi,Pakistan

This survey was carried out to evaluate the occurrence of total aflatoxins (AFs; B₁+B₂+G₁+G₂) in unpacked composite spices. A total of 75 samples of composite spices such as biryani, karhai, tikka, nihari and korma masalas were collected from local markets of Karachi, Pakistan, and analysed using HPLC technique. The results indicated that AFs were detected in 77% (n = 58) samples ranging from 0.68 to 25.74 µg kg^?1 with a mean of 4.63 ± 0.95 µg kg^?1. In 88% (n = 66) samples, AFs level was below the maximum limits (ML = 10 µg kg^?1) as imposed by EU. Furthermore, 61% (n = 46) tested samples contained AFs level between 1 and 10 µg kg^?1, 9% (n = 7) exhibited AFs contamination ranged 10?20 µg kg^?1 and only 3% (n = 2) of the investigated samples contained AFs levels higher than the ML of 20 µg kg^?1 for total aflatoxins as set by the USA. It was concluded that there is need to establish a strict and continuous national monitoring plan to improve safety and quality of spices in Pakistan.     

Aflatoxin B1 and aflatoxins in ground red chilli pepper after drying

In this study, 180 red chilli pepper (RCP) berry samples were obtained from two different croplands of Gaziantep and Kahramanmara? (Turkey) in August, September and October. RCP berry samples were dried under sunlight and grinded. Ground red chilli pepper (GRCP) samples were analysed for aflatoxins (AFs, sum of B₁, B₂, G₁ and G₂) and AFB₁ contamination. According to the results, in 49 of 180 samples, AFB₁ and in 37 samples, AFs were higher than legal limits. The lowest amounts of AFs and AFB₁ were obtained in August and the highest amounts in October. χ² analysis showed that there were no significant differences (p > 0.05) between cities among 3 months according to number of samples with AFs and AFB₁ above legal limits. According to the Duncan multiple-range test, there was no significant difference between all months. Strict measures are necessary to produce high-quality GRCP. RCP berry must be treated to reduce moulds before production of GRCP.     

Influence of storage environment on maize grain: CO2 production,dry matter losses and aflatoxins contamination

Poor storage of cereals, such as maize can lead to both nutritional losses and mycotoxin contamination. The aim of this study was to examine the respiration of maize either naturally contaminated or inoculated with Aspergillus flavus to examine whether this might be an early and sensitive indicator of aflatoxin (AF) contamination and relative storability risk. We thus examined the relationship between different interacting storage environmental conditions (0.80–0.99 water activity (a_w) and 15–35°C) in naturally contaminated and irradiated maize grain + A. flavus on relative respiration rates (R), dry matter losses (DMLs) and aflatoxin B1 and B2 (AFB1-B2) contamination. Temporal respiration and total CO₂ production were analysed by GC-TCD, and results used to calculate the DMLs due to colonisation. AFs contamination was quantified at the end of the storage period by HPLC MS/MS. The highest respiration rates occurred at 0.95 a_w and 30–35°C representing between 0.5% and 18% DMLs. Optimum AFs contamination was at the same a_w at 30°C. Highest AFs contamination occurred in maize colonised only by A. flavus. A significant positive correlation between % DMLs and AFB1 contamination was obtained (r = 0.866, p < 0.001) in the irradiated maize treatments inoculated with A. flavus. In naturally contaminated maize + A. flavus inoculum loss of only 0.56% DML resulted in AFB1 contamination levels exceeding the EU legislative limits for food. This suggests that there is a very low threshold tolerance during storage of maize to minimise AFB1 contamination. This data can be used to develop models that can be effectively used in enhancing management for storage of maize to minimise risks of mycotoxin contamination.     

Reversal of toxigenic effects of aflatoxin B1 on cockerels by alcoholic extract of African nutmeg,Monodora myristica

The reversal of the toxigenic effects of crystalline aflatoxin B₁ (AFB₁; from Aspergilus flavus) on cockerels using different concentrations of the ethanolic extract from the seeds of African nutmeg, Monodora myristica, was studied in 130 two‐week‐old cockerels, randomly divided into 13 groups (A–M) of ten birds each. Group A (controls) received 100 µl of phosphate‐buffered saline, while those in the test groups B, C and D received 690 ng, 1380 ng or 2010 ng of AFB₁, respectively; groups E to M received the three doses of AFB₁ with either 0.1, 0.2 or 0.3 ml of the extract of M myristica, respectively, 5 min after administration of AFB₁. Jugular blood, collected on days 14 and 21 after administration, was analysed for haematology parameters, serum proteins, alanine aminotransaminase (ALT), aspartate aminotransaminase (AST) and γ‐glutamyl transferase (GGT) levels. The birds were observed daily for clinical signs and mortality for 21 days. Post‐mortem examination was carried out on the livers of dead birds and those sacrificed by exsanguination after the 21 days post‐administration. One hundred per cent mortality was recorded in cockerels that received high doses of only AFB₁ within 72 h (2010 ng per bird), and between 17 and 19 days (1380 ng). The cockerels developed leucocytosis and microcytic hypochromic anaemia. Dosing with 0.2 or 0.3 ml of the extract of M myristica reversed these changes over time, while the lowest dose (0.1 ml) did not. While serum bilirubin levels rose significantly in test cockerels, no significant changes (P > 0.05) were observed in the levels of serum proteins of control and test cockerels, whether or not they received the extract of M myristica. Aflatoxicosis caused significant decreases and increases (P < 0.05) in serum AST and GGT levels, respectively, while the administration of alcoholic extract of M myristica reversed the GGT but not AST levels to normal. Livers from control cockerels and those given 2010 ng of AFB₁ showed no appreciable gross or histological lesions. The other groups showed mild to moderate hepatomegaly, paleness and friability, diffuse vacuolar degeneration and necrosis, Kupffer cell proliferation, presence of megalocytes and multinucleated hepatocytes. Cockerels that received 0.2 or 0.3 ml of extract of M myristica, irrespective of the dose of AFB₁ showed the mildest hepatic lesions. The results of this study show that AFB₁ is highly toxigenic to cockerels and that this could be successfully reversed by the concurrent administration of alcoholic extract of M myristica. It is therefore recommended that reduction of fungal growth on foods and subsequent toxicosis by aeration, cooling, modified atmospheres or by fungistats, is complemented with the use of extracts of spices from M myristica seed, a tree widely distributed along the west coast and central Africa. Copyright © 2004 Society of Chemical Industry     

Assessment of azole fungicides as a tool to control growth of Aspergillus flavus and aflatoxin B1 and B2 production in maize

ABSTRACT

Aspergillus flavus is a highly aflatoxin (AF)-producing species infecting maize and other crops. It is dominant in tropical regions, but it is also considered an emerging problem associated with climate change in Europe. The aim of this study was to assess the efficacy of azole fungicides (prochloraz, tebuconazole and a 2:1 (w/w) mixture of prochloraz plus tebuconazole) to control the growth of A. flavus and AF production in yeast-extract–sucrose (YES) agar and in maize kernels under different water activities (a_w) and temperatures. Aflatoxins B₁ and B₂ were determined by LC with fluorescence detection and post-column derivatisation of AFB₁. In YES medium and maize grains inoculated with conidia of A. flavus, the growth rate (GR) of the fungus and AFB₁ and AFB₂ production were significantly influenced by temperature and treatment. In YES medium and maize kernels, optimal temperatures for GR and AF production were 37 and 25°C, respectively. In maize kernels, spore germination was not detected at the combination 37ºC/0.95 a_w; however, under these conditions germination was found in YES medium. All fungicides were more effective at 0.99 than 0.95 a_w, and at 37 than 25ºC. Fungicides effectiveness was prochloraz > prochloraz plus tebuconazole (2:1) > tebuconazole. AFs were not detected in cultures containing the highest fungicide doses, and only very low AF levels were found in cultures containing 0.1 mg l^–1 prochloraz or 5.0 mg l^–1 tebuconazole. Azoles proved to be highly efficient in reducing A. flavus growth and AF production, although stimulation of AF production was found under particular conditions and low-dosage treatments. Maize kernels were a more favourable substrate for AF biosynthesis than YES medium. This paper is the first comparative study on the effects of different azole formulations against A. flavus and AF production in a semi-synthetic medium and in maize grain under different environmental conditions.     

Enzymatic hydrolysis combined with high‐pressure homogenisation for the preparation of polysaccharide‐based nanoparticles from the by‐product of Flammulina velutipes

In this study, protease, α‐amylase and 5‰ β‐glucanase enzymolysis in combination with high‐pressure homogenisation were used for the preparation of polysaccharide‐based nanoparticles from Flammulina velutipes stipes, respectively, named FNP‐1, FNP‐2 and FNP‐3, and the nanoparticles were subsequently characterised. The FNP size distribution ranged from 50 nm to 300 nm, among which FNP‐2 and FNP‐3 were smaller than FNP‐1, based on the SEM images. GC‐MS results showed that these particles were mainly composed of glucose and glucosamine. The FNP dispersions at 1 wt% behaved as non‐Newtonian, shear‐thinning fluids, and the FNP‐3 dispersion presented superior viscoelasticity. With an increasing degree of enzymolysis, the thermal stability of the FNPs decreased. In addition, these particles presented various cation‐exchange properties. Therefore, the Flammulina velutipes polysaccharide‐based nanoparticles obtained from this study can be potentially used as a promising functional food ingredient in the food industry.     

Occurrence of aflatoxins in milk thistle herbal supplements

Milk thistle (MT) dietary supplements are widely consumed due to their possible liver-health-promoting properties. As botanicals they can be contaminated with a variety of fungi and their secondary metabolites, mycotoxins. The aflatoxigenic fungus Aspergillus flavus has been previously isolated from these commodities. Currently, there is no published method for determining aflatoxins (AFs) in MT. Therefore, a liquid chromatography (LC) method validated for aflatoxin analysis in botanicals was evaluated and applied to MT. The method consisted of acetonitrile/water extraction, immunoaffinity column clean-up, LC separation, post-column photochemical reaction derivatisation and fluorescence detection. The average recoveries for AFs added to MT seeds, herb, oil-based liquid extract and alcohol-based liquid extract were 76% or higher. The mean relative standard deviation was <10%. The limit of detection (LOD) was 0.01?µg kg^?1 and the limit of quantification (LOQ) was 0.03?µg kg^–1. The method was used to conduct a small survey. A total of 83 MT samples from the US market were analysed. AFs were detected in 19% of the samples with levels ranging from 0.04 to 2.0?µg kg^–1. Additionally, an aflatoxigenic A. flavus strain from ATTC and an A. parasiticus strain isolated from MT herb powder were found to produce high amounts of aflatoxins (11,200 and 49,100?µg kg^–1, respectively) when cultured in MT seed powder. This is the first study reporting on aflatoxin contamination of MT botanical supplements and identifying methodology for AF analysis of these commodities.     

Transfer of aflatoxin B1 and fumonisin B1 from naturally contaminated raw materials to beer during an industrial brewing process

The aim of this research was to determine the fate of aflatoxins (AFs) and fumonisins (FBs) naturally occurring in raw materials (maize grit and malted barley) during four industrial brewing processes. The aflatoxin B₁ (AFB₁) level in raw materials varied from 0.31 to 14.85 µg kg^?1, while the fumonisin B₁ (FB₁) level (only in maize grit) varied from 1146 to 3194 µg kg^?1. The concentration in finished beer ranged from 0.0015 to 0.022 µg l^?1 for AFB₁ and from 37 to 89 µg l^?1 for FB₁; the other aflatoxins and fumonisin B₂ were not found in beer samples. The average percentage of toxins recovered in finished beer, referring to the amounts contained in raw materials, were 1.5% ± 0.8% for AFB₁ and 50.7% ± 4.7% for FB₁. These results were mainly due to the different solubility of the two mycotoxins during the mashing process. If raw materials comply with the limits fixed by European Commission Regulations, the contribution of a moderate daily consumption of beer to AFB₁ and FB₁ intake does not contribute significantly to the exposure of the consumer.     

Maize populations with resistance to field contamination by aflatoxin B1

Maize (Zea mays L) germplasm is needed with resistance to infection by Aspergillus flavus and/or subsequent contamination by aflatoxin B₁ (AFB₁). A select group of maize populations were evaluated for their resistance to AFB₁ contamination at three locations. Four populations (Ibadan B and three others derived from crosses between Corn Belt inbreds and diploid perennial teosinte. Zea diploperennis) were compared with a susceptible hybrid check in a randomised complete block experiment with 10 replicates in Georgia, Missouri and South Carolina for two years. Ears were not inoculated, and naturally occurring concentrations of AFB₁ in harvested grain were analysed for population differences. Ibadan B and Mo2 W × Z diploperennis had significantly lower average amounts of AFB₁, 19 μg kg^?1 and 18 μg kg^?1, respectively, than other test entries. Backcrossing to susceptible Corn Belt inbreds produced populations as susceptible as the check when resistance was measured as the concentrations of AFB₁ in the grain. The consistency and significance of low AFB₁ concentrations for Ibadan B and Mo20W × Z diploperennis suggest that these may be useful sources of resistance.     

Survey of aflatoxins in maize tortillas from Mexico City

In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure. In a survey of 396 2-kg samples, taken over four sampling days in 2006 and 2007 from tortilla shops and supermarkets in Mexico City, aflatoxin levels were quantified by HPLC. In Mexico, the regulatory limit is 12?µg?kg^?1 total aflatoxins for maize tortillas. In this survey, 17% of tortillas contained aflatoxins at levels of 3–385?µg?kg^?1 or values below the limit of quantification (<LOQ) and, of these, 13% were >12?µg?kg^?1 and 87% were below the regulatory limit. Average aflatoxin concentrations in 56 contaminated samples were: AFB₁ (12.1?µg?kg^?1); AFB₂ (2.7?µg?kg^?1); AFG₁ (64.1?µg?kg^?1) and AFG₂ (3.7?µg?kg^?1), and total AF (20.3?µg?kg^?1).     

Elucidation of antifungal toxicity of Callistemon lanceolatus essential oil encapsulated in chitosan nanogel against Aspergillus flavus using biochemical and in-silico approaches

ABSTRACT

The antifungal and aflatoxin B₁ (AFB₁) inhibitory effect of chemically characterised Callistemon lanceolatus essential oil (CLEO), chitosan nanoparticles, and CLEO loaded chitosan nanoparticles (CLEO-ChNPs) were investigated. Scanning electron microscope observation exhibited the spherical shape of prepared CLEO-ChNPs with an average range of 20–70 nm. An in-vitro release study revealed the controlled volatilisation of CLEO from CLEO-ChNPs. The CLEO-ChNPs caused complete inhibition of growth (4.5 µl/ml) and AFB₁ (4.0 µl/ml) production by A. flavus at a low dose compared to free CLEO (5.0 µl/ml). The antifungal and AFB₁ inhibitory toxicity of CLEO-ChNPs were elucidated using biochemical (effect on ergosterol biosynthesis, membrane cations, mitochondrial membrane potential, C-sources utilisation and cellular methylglyoxal level) and in-silico (interaction with the gene product Erg 28, Cytochrome c oxidase subunit Va, Omt-A, Ver-1, and Nor-1) approaches.     

Aflatoxins distribution in fractions derived from tofu production

ABSTRACT

Tofu or bean curd is obtained from soybean seeds being a widespread food product in Asia. The commodity used for its production can be contaminated with aflatoxins, which are secondary metabolites synthetised by species of Aspergillus flavus and A. parasiticus. Intake of contaminated food products causes toxic effects on consumers. The aim of this work was to study aflatoxin distribution in fractions obtained from pilot-scale tofu production with contaminated soybeans. The presence of the aflatoxins B₁, B₂, G₁ and G₂ (AFs) in soaking water, okara, whey and tofu was analysed. Aflatoxin analysis was performed by HPLC with fluorescence detection. The distribution of aflatoxins in all the analysed fractions was not a normal distribution. The liquid fractions (soaking water and whey) had less contamination than solid fractions (tofu and okara). The percentage AFB₁ remaining in nutritionally important fractions, okara and tofu, was between 6.2% and 67.7% (median = 18.1%) and 0.5% and 13.2% (median = 3.5%), respectively. AFB₂, AFG₁ and AFG₂ had a similar distribution. These results showed that throughout tofu production, AFs can be present in the products intended for human consumption.     

The control of Aspergillus flavus with Cinnamomum jensenianum Hand.-Mazz essential oil and its potential use as a food preservative

The essential oil extracted from the bark of Cinnamomum jensenianum Hand.-Mazz was tested for antifungal activity against Aspergillus flavus. Fifty-five components accounting for 96.66% of the total oil composition were identified by GC–MS. The major components were eucalyptol (17.26%) and α-terpineol (12.52%). Mycelial growth and spore germination was inhibited by the oil in a dose-dependent manner. The oil also exhibited a noticeable inhibition on the dry mycelium weight and the synthesis of aflatoxin B₁ (AFB₁) by A. flavus, completely restraining AFB₁ production at 6 μl/ml. The possible mode of action of the oil against A. flavus is discussed based on changes in the mycelial ultrastructure. To confirm the target of the oil in the plasma membrane, studies on the inhibition of ergosterol synthesis were performed. Results show that the oil caused a considerable reduction in the ergosterol quantity. Thus, the essential oil from C. jensenianum can be used as a potential source for food preservative.