Use of a modified QuEChERS method for the determination of mycotoxin residues in edible nuts by nano flow liquid chromatography high resolution mass spectrometry.
A nanoflow liquid chromatography high resolution mass spectrometry method for the quantification of mycotoxins in nuts has been developed. Two strategies based on QuEChERS methodology were evaluated. Thus, EMR-lipid was compared with a conventional mixture of PSA and C18 dispersive solid phase extraction sorbents which have been commonly used in this type of matrices as sample clean-up. The results showed that the use of EMR-lipid reduced more effectively matrix components, achieving a negligible matrix effect for all mycotoxins studied in peanut, pistachio and almond. The proposed method was validated in line with SANTE guidelines using EMR-Lipid as dispersive solid phase extraction sorbent. The lowest concentration level were between 0.05 and 5 μg kg-1, being lower than the maximum levels established by the current legislation. Recovery rates ranged from 75% to 98% was obtained in all sample studied, achieving also satisfactory precision with RSD values lower than 19% in all cases.
Assessing Aflatoxin Exposure Risk from Peanuts and Peanut Products Imported to Taiwan.
Aflatoxins are highly toxic and cause disease in livestock and humans. In order to assess Taiwan population exposure to aflatoxin from peanuts and peanut products, a total of 1089 samples of peanut candy, peanut butter, and peanuts etc. were collected in the period from 2011 to 2017 and analyzed using a liquid chromatography/tandem mass spectrometer. The overall mean contamination levels of aflatoxin in peanuts and peanut products were 2.40 μg/kg of aflatoxin B1, 0.41 μg/kg of aflatoxin B2, 0.19 μg/kg of aflatoxin G1, and 0.03 μg/kg of aflatoxin G2. We use margin of exposure (MOE) as a tool to improve food safety management. According to MOE levels of aflatoxins in peanuts and peanut products from China, Indonesia, Thailand, the United States, and the Philippines were above the safe lower limit of 10,000, indicating an absence of public health or safety risk for the majority of the population. However, products from Vietnam were under the MOE safe lower limit, suggesting that regulatory actions must be continued to avoid excessive consumer exposure.
Aptamer as capture agent in enzyme-linked apta-sorbent assay (ELASA) for ultrasensitive detection of Aflatoxin B1.
Aflatoxin B1 (AFB1), is one of the most toxic mycotoxins found to contaminate various food commodities like cereals, dried fruits, tree nuts, spices and crude vegetable oils. In spite of considerable progress in analytical techniques, there is still a need to develop rapid and highly sensitive detection platforms for AFB1. In this study, AFB1 specific aptamer was used as a capture molecule to develop an enzyme-linked apta-sorbent assay (ELASA) for ultrasensitive detection of AFB1. Under optimized conditions, the assay had a linear detection range from 1 μg to 1 pg with a limit of detection (LOD) of 1 pg/mL in buffer. Conventional ELISA with AFB1 hapten as the capture agent (LOD = 10 pg/mL) was also carried out to compare the results with the present method. Recovery studies in food samples like dried red chillies, groundnut and pepper using both the methods was found to be in the range of 88.49-106.4% at 10 ng/mL and 87.4% to 95.8% at 5 ng/mL for ELASA and 76.56-127.68% at 10 ng/mL and 82-101.2% at 5 ng/mL for ELISA. Higher detection (10 fold) and better recovery using ELASA suggest that the method could offer an early, ultrasensitive, high-throughput, qualitative and semi-quantitative detection of AFB1 in contaminated food samples.
A Critical Review of Aflatoxin Contamination of Peanuts in Malawi and Zambia: The Past, Present, and Future.
Peanut (Arachis hypogaea L.) is an important crop in Malawi and Zambia. The crop is valued for soil improvement in cereal-based cropping systems, for improving the livelihoods of farming households who consume it and also sell it for cash, and for earning foreign exchange when exported. Research and development efforts have resulted in an increase in both peanut production area and productivity. However, a key challenge that still needs to be solved in these countries is how to produce peanuts with acceptable levels of aflatoxin contamination. Data continues to show that aflatoxin continues to be a problem in both formal and informal trade. As a result, unlike 30 years ago, most of the peanut trade has now shifted to domestic and regional markets that do not restrict the sale of aflatoxin-contaminated peanuts. Impacts of aflatoxin contamination on health and also on the full cost burden of control are not well documented. Technologies are available for mitigating against aflatoxin contamination. The advantages, disadvantages, and gaps associated with these technologies are discussed. Considerable money and effort continues to be invested in Malawi and Zambia into mitigating aflatoxin contamination, but evidence of long-term success is limited. Based on past and current initiatives, the prospects of eliminating aflatoxin in the near future at the household level and in trade are not promising.
Reveal Q+ MAX® for Detection of Total Aflatoxin in Corn, Almonds, Pistachios, Walnuts, and Peanuts.
Background: The Reveal Q+ MAX for Aflatoxin is a lateral flow immunochromatographic test intended for quantitative analysis within 6 min after aqueous extraction. Objective: Work was conducted to validate the performance of the Reveal Q+ MAX for Aflatoxin method in selected corn and nut matrixes. Methods: This method was validated under the requirements of the AOAC Research Institute Performance Tested MethodSM program. Five matrixes, including corn naturally contaminated with aflatoxin at 0, 5.2, 21.0, 51.6, 103.6, and 282 ppb as well as peanuts, pistachios, walnuts, and almonds spiked at 0, 5, 20, 50, and 300 ppb were analyzed. Results: Average percentage recoveries of the added aflatoxin from the matrixes ranged from 80.8 to 116.9%. Average LOD for all matrixes is 2 ppb and LOQ is 7 ppb. With the exception of sample size for almonds, robustness trials demonstrated that deliberate changes to the assay parameters minimally affected the Reveal Q+ MAX assay performance. Finally, stability results from three independently manufactured lots support Reveal Q+ MAX for Aflatoxin performance consistency and shelf-life of 18 months when stored at room temperature. Conclusions: This study appropriately validates the Performance Tested MethodSM claim for corn and selected nut matrixes on Reveal Q+ MAX for Aflatoxin, an aqueous lateral flow test kit. Highlights: Aqueous lateral flow test kit detects total aflatoxin between 80 to 120% yield with an LOD of 2 ppb.
Aflatoxin in foodstuffs: Occurrence and recent advances in decontamination.
Aflatoxins are highly toxic compounds produced as secondary metabolites by some Aspergillus species, whose occurrence have been reported predominantly in several types of foods of low moisture content, while aflatoxin biotransformation products have been reported mainly in milk and milk products. This review deals with the occurrence of aflatoxins in some of the major food products in the last 5 years including regulatory aspects, and recent advances in detoxification strategies for contaminated foods. Aflatoxin contamination in cereals including corn and peanut is still a public health problem for some populations, especially in African countries. Despite that most of physical and chemical methods for aflatoxin detoxification may affect the nutritional properties of food, or are not safe for human consumption, gamma-radiation and ozone applications have demonstrated great potential for detoxification of aflatoxins in some food matrices. Biological methods based on removal or degradation of aflatoxins by bacterial and yeast have good perspectives, although further studies are needed to clarify the detoxification mechanisms by microorganisms and determine practical aspects of the use of these methods in food products, especially their potential effects on sensory characteristics of foods.
Thermal inactivation of Aspergillus flavus in peanut kernels as influenced by temperature, water activity and heating rate.
Infection of Aspergillus flavus, which can produce aflatoxin, is a major problem for peanut safe storage. Thermal inactivation kinetics of Aspergillus flavus is essential to design an effective heat treatment process. In this study, thermal inactivation kinetics of Aspergillus flavus in peanut kernel flour at four water activity (aw) levels (0.720, 0.783, 0.846, and 0.921) with three temperatures for each aw was studied using a thermal-death-time heating block system and fitted with first-order kinetic and Weibull models. The influence of heating rates on thermotolerance of Aspergillus flavus was also investigated. The results showed that the Weibull distribution model had better coefficient of determination from 0.954 to 0.996, as compared to that (from 0.866 to 0.980) of the first-order kinetic model. An upward concavity was found with the inactivation curve, indicating a tailing effect. Model parameters (D, δ, and p) were estimated with the modified Bigelow equations to predict survival curves of Aspergillus flavus at any temperature and aw. The reduced heat resistance of Aspergillus flavus at high heating rates above 1 °C/min suggests that developing fast thermal processes is preferred for pasteurizing peanuts in food industry. A case study was presented for applying the cumulated lethal time model to design the industrial heating process based on the thermal kinetics of Aspergillus flavus.
New tools to screen wild peanut species for aflatoxin accumulation and genetic fingerprinting.
BACKGROUND: Aflatoxin contamination in peanut seeds is still a serious problem for the industry and human health. No stable aflatoxin resistant cultivars have yet been produced, and given the narrow genetic background of cultivated peanuts, wild species became an important source of genetic diversity. Wild peanut seeds, however, are not abundant, thus, an effective method of screening for aflatoxin accumulation using minimal seeds is highly desirable. In addition, keeping record of genetic fingerprinting of each accession would be very useful for breeding programs and for the identification of accessions within germplasm collections. RESULTS: In this study, we report a method of screening for aflatoxin accumulation that is applicable to the small-size seeds of wild peanuts, increases the reliability by testing seed viability, and records the genetic fingerprinting of the samples. Aflatoxin levels observed among 20 wild peanut species varied from zero to 19000 ng.g-1 and 155 ng.g-1 of aflatoxin B1 and B2, respectively. We report the screening of 373 molecular markers, including 288 novel SSRs, tested on 20 wild peanut species. Multivariate analysis by Neighbor-Joining, Principal Component Analysis and 3D-Principal Coordinate Analysis using 134 (36 %) transferable markers, in general grouped the samples according to their reported genomes. The best 88 markers, those with high fluorescence, good scorability and transferability, are reported with BLAST results. High quality markers (total 98) that discriminated genomes are reported. A high quality marker with UPIC score 16 (16 out of 20 species discriminated) had significant hits on BLAST2GO to a pentatricopeptide-repeat protein, another marker with score 5 had hits on UDP-D-apiose synthase, and a third one with score 12 had BLASTn hits on La-RP 1B protein. Together, these three markers discriminated all 20 species tested. CONCLUSIONS: This study provides a reliable method to screen wild species of peanut for aflatoxin resistance using minimal seeds. In addition we report 288 new SSRs for peanut, and a cost-effective combination of markers sufficient to discriminate all 20 species tested. These tools can be used for the systematic search of aflatoxin resistant germplasm keeping record of the genetic fingerprinting of the accessions tested for breeding purpose.
Microbiological Quality and Risk Assessment for Aflatoxins in Groundnuts and Roasted Cashew Nuts Meant for Human Consumption.
Nuts are one of the commonly consumed snacks but poor handling and storage practices can make them prone to foodborne infections. The study aimed at assessing the microbiological quality and risk assessment for aflatoxins in groundnuts and cashew nuts consumed in selected locations in Nigeria. The moisture content, colony counts, incidence of pathogenic bacteria, aflatoxin contamination, and risk assessment for aflatoxins were evaluated using standard methods. The moisture content and total viable count ranged from 5.00-8.60% and 5.5-89 × 103 cfug-1, respectively, while the fungal count was between 4-24 × 103 and 1.0-4.5 × 102 cfug-1, respectively. Eleven fungal species belonging to 5 genera were isolated from the nuts, with Aspergillus flavus, Rhizopus oryzae, and Fusarium oxysporum having the highest percentage occurrence of 50%. In addition, the aflatoxin concentration ranged 0.1-6.8 and 29-33.78 ng kg-1 for cashew nuts and groundnuts, respectively. The margin of exposure (MOE) to aflatoxin contamination was 6.10 for groundnuts and 1000 for cashew nuts and the nuts consumers were at a risk of exposure to foodborne diseases and aflatoxin contamination with mean exposure values of 27.96 and 0.17 ng kg-1bwday-1, respectively. The risk of primary liver cancer for groundnuts and cashew nuts consumers was also estimated to be 1.38 and 0.01 canceryear-1100,000-1person, respectively. This calls for mitigation measures from appropriate governmental organizations.
Aflatoxin contamination in nuts marketed in Italy: preliminary results.
BACKGROUND: Aflatoxins (AFs) are one of the main groups of mycotoxins produced by molds. Nuts, although recognized as a food with health benefits, are frequently contaminated by AFs. STUDY DESIGN:
In this preliminary study we evaluated the contamination by total AFs and AFB1 in different types of nuts from different countries marketed in Apulia. METHODS: Overall, 124 samples (almonds, apricot kernels, chestnuts, hazelnuts, peanuts, pistachios, walnuts and Brazil nut) were analyzed using an High-Performance Liquid Chromatography system. RESULTS: Twenty samples (16.1%) were contaminated with AFs of which 55% were non-compliant, according to Reg. 165/2010. The median values (µg/kg) of total AFs and AFB1 were 16.6 and 15.1, respectively. Pistachios appeared more susceptible to AF contamination than the other nuts, with levels of total AFs ranging from 8.8 to 387.3 µg/kg and of AFB1 from 8.2 to 354.5 µg/kg. The majority of contaminated samples came from Asia and AF contamination was different in the various Asiatic sub-regions: regardless of the type of nuts, samples from Western Asia were the least contaminated. CONCLUSIONS: As geographical origin may influence the risk of contamination, in order to protect human health, customer countries should increase AF monitoring in nuts coming from those countries with favorable environments for the growth of aflatoxigenic molds or with less strict regulations.