Removal of aflatoxin B1 in edible plant oils by oscillating treatment with alkaline electrolysed water
Alkaline electrolysed water (AlEW) with different pHs was produced by an electrolysed water generator through adjusting the electric current and voltage. The produced AlEW had a pH above 10, and a low oxidation–reduction potential (ORP) of less than −560 mV. In the current study, the effectiveness of AlEW on decontamination of aflatoxin B1 (AFB1) in various edible plant oils was investigated. The character of AlEW, oil type and the volume of AlEW were major factors which could influence the AFB1 elimination effectiveness. AlEW with pH 12.2 had the greater potential to remove AFB1. When 10 ml AlEW with pH 12.2 were added to 5 g peanut oil or olive oil (fortified level at 40 μg kg−1), followed by oscillation for 5 min at 20 °C, the removal rate of AFB1 could reach nearly 100%. The volume of AlEW needed to completely remove the AFB1 varied with the pH of AlEW and with the oil type. The degradation products of AFB1 were also investigated.
Mycobiota, aflatoxins and cyclopiazonic acid in stored peanut cultivars
This study evaluated the presence of fungi and mycotoxins [aflatoxins (AFs), cyclopiazonic acid (CPA), and aspergillic acid] in stored samples of peanut of cultivars Runner IAC Caiapó and cultivar Runner IAC 886 during 6 months. A total of 70 pod and 70 kernel samples were directly seeding onto Aspergillus flavus and parasiticus agar for fungi isolation and aspergillic acid detection, and AFs and CPA were analyzed by high-performance liquid chromatography. The results showed the predominance of Aspergillus section Flavi strains, Aspergillus section Nigri strains, Fusarium spp., Penicillium spp. and Rhizopus spp. from both peanut cultivars. AFs were detected in 11.4% in kernel samples of the two cultivars and in 5.7% and 8.6% of pod samples of the Caiapó and 886 cultivars, respectively. CPA was detected in 60.0% and 74.3% of kernel samples of the Caiapó and 886 cultivars, respectively. Co-occurrence of both mycotoxins was in observed in 11.4% of kernel samples of the two cultivars. These results indicate a potential risk of aflatoxin production if good storage practices are not applied. In addition, the large number of samples contaminated with CPA and the simultaneous detection of AFs and CPA highlight the need to investigate factors related to the control and co-occurrence of these toxins in peanuts.
Polyphasic approach to the identification of Aspergillus section Flavi isolated from Brazil nuts
The aim of this study was to use a polyphasic approach to identify Aspergillus section Flavi isolated from Brazil nuts collected in the Amazon forest: investigation of macro- and microscopic morphology, production of extrolites, heat-resistance fungi, and sequencing of DNA regions. The following Aspergillus section Flavi species were identified: Aspergillus flavus (75.5%), Aspergillus nomius (22.3%), and Aspergillus parasiticus (2.2%). All A. nomius and A. parasiticus isolates produced aflatoxins B and G, but not cyclopiazonic acid (CPA). A. flavus isolates were more diversified and a high frequency of mycotoxigenic strains was observed. The polyphasic approach permitted the reliable identification of section Flavi species. The rate of mycotoxigenic strains was high (92.7%) and mainly included A. flavus strains producing elevated levels of aflatoxins and CPA. These results highlight the possibility of co-occurrence of both toxins, increasing their potential toxic effect in this commodity.
Mycobiota and mycotoxins in Brazil nut samples from different states of the Brazilian Amazon region
The objective of this study was to evaluate the presence of fungi and mycotoxins (aflatoxins and cyclopiazonic acid) in Brazil nut samples collected in different states of the Brazilian Amazon region: Acre, Amazonas, Amapá, and Pará. A total of 200 husk samples and 200 almond samples were inoculated onto Aspergillus flavus-parasiticus agar for the detection of fungi. Mycotoxins were analyzed by high-performance liquid chromatography. The mycobiota comprised the following fungi, in decreasing order of frequency: almonds - Phialemonium spp. (54%), Penicillium spp. (16%), Fusarium spp. (13%), Phaeoacremonium spp. (11%), and Aspergillus spp. (4%), husks - Phialemonium spp. (62%), Phaeoacremonium spp. (11%), Penicillium spp. (10%), Fusarium spp. (9%), and Aspergillus spp. A polyphasic approach was used for identification of Aspergillus species. Aflatoxins were detected in 22 (11%) of the 200 almond samples, with 21 samples presenting aflatoxin B1 levels above 8 μg/kg, the limit established by the European Commission for Brazil nuts for further processing. Nineteen (9.5%) of the 200 husk samples contained aflatoxins, but at levels lower than those seen in almonds. Cyclopiazonic acid (CPA) was detected in 44 (22%) almond samples, with levels ranging from 98.65 to 161.2 μg/kg. Aspergillus nomius and A. flavus were the most frequent Aspergillus species. The presence of fungi does not necessarily imply mycotoxin contamination, but almonds of the Brazil nut seem to be a good substrate for fungal growth.
Modelling Aspergillus flavus growth and aflatoxins production in pistachio nuts
Aflatoxins (AFs) are the main contaminants in pistachio nuts. AFs production in pistachio has been attributed to Aspergillus flavus. The aim of this study was to apply existing models to predict growth and AFs production by an A. flavus isolated from pistachios as a function of moisture content and storage temperature of pistachios in order to test their usefulness and complementarities. A full factorial design was used: the moisture content levels assayed were 10, 15, 20, 25 and 30% and incubation temperatures were 10, 15, 20, 25, 30, 37 and 42 °C. Both kinetic and probability models were built to predict growth of the strain under the assayed conditions. Among the assayed models, cardinal ones gave a good quality fit for radial growth rate data. Moreover, the progressive approach, which was developed based on a reduced number of experimental points led to an improved prediction in the validation step. This is quite significant as may allow for improved experimental designs, less costly than full factorial ones. Probability model proved to be concordant in 91% of the calibration set observations. Even though the validation set included conditions around the growth/no-growth interface, there was a 100% agreement in the predictions from the data set (n = 16, cut off = 0.5) after 60 days. Similarly, the probability for AF presence was rightly predicted in 89% of the cases. According to our results EC maximum aflatoxin levels would be surpassed in a period as short as 1 month if pistachio nuts reach 20 °C, unless %mc is ≤10%.
Determination of aflatoxin risk components for in-shell Brazil nuts
A study was conducted on the risk from aflatoxins associated with the kernels and shells of Brazil nuts. Samples were collected from processing plants in Amazonia; Brazil. A total of 54 test samples (40 kg) were taken from 13 in-shell Brazil nut lots ready for market. Each in-shell sample was shelled and the kernels and shells were sorted in five fractions: good kernels; rotten kernels; good shells with kernel residue; good shells without kernel residue; and rotten shells; and analysed for aflatoxins. The kernel : shell ratio mass (w/w) was 50.2/49.8%. The Brazil nut shell was found to be contaminated with aflatoxin. Rotten nuts were found to be a high-risk fraction for aflatoxin in in-shell Brazil nut lots. Rotten nuts contributed only 4.2% of the sample mass (kg); but contributed 76.6% of the total aflatoxin mass (µg) in the in-shell test sample. The highest correlations were found between the aflatoxin concentration in in-shell Brazil nuts samples and the aflatoxin concentration in all defective fractions (R (2 )= 0.97). The aflatoxin mass of all defective fractions (R (2 )= 0.90) as well as that of the rotten nut (R (2 )= 0.88) were also strongly correlated with the aflatoxin concentration of the in-shell test samples. Process factors of 0.17; 0.16 and 0.24 were respectively calculated to estimate the aflatoxin concentration in the good kernels (edible) and good nuts by measuring the aflatoxin concentration in the in-shell test sample and in all kernels; respectively.
Aflatoxin B1 in post-harvest peanuts and dietary risk in China
To monitor the aflatoxin contamination status in raw peanuts and evaluate the effect on public health; 1040 samples were collected from four agro-ecological zones throughout 12 provinces from 2009 to 2010 in China and then analyzed for aflatoxin B1 (AFB1) levels using High Pressure Liquid Chromatography (HPLC) and immunoaffinity columns. The results revealed that AFB1 was detected in 25% of the samples; ranging from 0.01 to 720 µg/kg. The Monte Carlo and bootstrap methods were employed to estimate AFB1 intake in children and adults and their potential liver cancer risk. The mean estimated intakes for children and adults were 0.218Â0.222 ng/kg body weight (bw)/day and 0.106Â0.108 ng/kg bw/day. The liver cancer risk; calculated by two approaches derived from the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and European Food Safety Authority (EFSA); were estimated at 0.003Â0.17 cancer cases/year/100;000 and 24.7Â1273 margins of exposure values; respectively. The results suggest that AFB1 contamination in raw peanuts and dietary risk was low; but essential surveillance measures should be taken to protect public health.