Aflatoxins In Foods Research Articles

Detection of Aflatoxins B1 in Maize Grains Using Fluorescence Resonance Energy Transfer

Aflatoxins are secondary metabolites of Aspergillus flavus and Aspergillus parasiticus. These fungal species are the most dangerous and common toxin group causing food contamination. Aflatoxin has high toxicity and can cause cancer to humans and animals. The quantitative detection of aflatoxin in food, therefore, plays a very important role. However, in practice, due to low concentrations, aflatoxin detection analysis methods need to be highly sensitive and simple to apply. In this report, the fluorescence resonance energy transfer method (FRET) adopts the donor–acceptor interaction of aflatoxin B1. The CdSe/ZnS quantum dot detection of aflatoxin B1 will be presented wherein the aflatoxin B1 concentration can be determined from the changes in fluorescence lifetime or fluorescence intensity. A fluorescence lifetime calibration curve versus aflatoxin B1 concentrations was established. Test results of aflatoxin B1 determination in maize in Vietnam by FRET method are consistent with the results of aflatoxin B1 determination by HPLC based on ppm concentration.

Quantification of carcinogenic aflatoxins in unprocessed foods and their implication for consumption in Lima, Peru

Introduction and objectives: aflatoxins are secondary metabolites produced by fungi of the Aspergillus and Penicillium geni. These fungi contaminate cereals and several other types of food. The pathophysiologic effects of aflatoxins in humans include liver cancer, cirrhosis, and accumulation in human tissues. The study aimed to quantify carcinogenic aflatoxins in unprocessed food sold in the foodstuff markets of 13 districts of the city of Lima, Perú, and to discuss their effects for public health. Methods: in order to so, we performed an immunoenzymatic assay using a Veratox® kit for total aflatoxin to detect aflatoxins in food for human consumption, and the implications of our findings for public health. Results: the most contaminated foods we found included peanuts (Arachis hypogaea) (149.7 ppb) from the Limoncillo market at the Rimac district, and "ají panca" or Peruvian red chili pepper (Capsicum chinense) (56.4 ppb) from the central market at the Comas district. Peanuts may be eaten raw in pasta or creams, and Capsicum chinense is also eaten sometimes raw, always in a sustained manner over time as part of typical Peruvian cuisine. Conclusions: we demonstrated a high risk to public health due to the link between aflatoxins in these foods and mainly liver cancer, in a city where the hepatic cancer and gastric cancer are prevalent.

Analysis of aflatoxins in foods retailed in Saudi Arabia using immunoaffinity column cleanup and high-performance liquid chromatography-fluorescence detection

A liquid–liquid extraction based high performance liquid chromatography-fluorescence method has been proposed for the quantitation of naturally producing aflatoxins in nuts and nut based products. Aflatoxins extraction from nuts and nut products was involved methanol – water extraction, immunoaffinity column cleanup followed by post column derivatization technique. The gel contents of monoclonal antibody of the column are very specific to the toxins of interest, which makes the extraction experiment rapid, simple, highly specific and sensitive. Additionally, the improve concentration of toxins from complex nuts and nut product matrices helps to reduced chromatography interference and lower limit of detection. The proposed method was authenticated to evaluate the performance in terms of linearity of the calibration, limit of detection, recovery, run-to-run (repeatability) and day-to-day precision (reproducibility). Good quality parameters with LOD between 0.003 and 0.007 ppb, recovery from 89 to 98%, linearity in the range of 0.02 to 100 ppb (r2 > 0.989) and precisions with RSDs were achieved below 4.5% at concentration level of 1.0 and 30.0 ppb. The developed method was effectively used to the analysis of aflatoxins (AFB1, AFB2, AFG1, and AFG2) in twenty nuts and nut products and were found up to 120.1 ng/mL AFB1 and 11.2 ppb AFB2 in few of the samples.

Relationship between serum aflatoxin concentrations and the nutritional status of children aged 6–24 months from Zambia

In Zambia, mothers/caregivers feed their children cereal-based complementary foods that are prone to aflatoxin contamination. This study evaluated the relationship between exposure to aflatoxins and the nutritional status of young children. It covered 400 mothers with children aged 6–24 months. Their nutritional status assessed by measuring weight and height using standard procedures. Serum samples analysed for aflatoxin B1-lysine (AFB1-lys), a reliable biomarker of aflatoxin exposure. Child sickness and age, exposure to aflatoxin in foods, and albumin-normalised AFB1-lys level were found to be significantly (p < .05) associated with child stunting except for child age that was not significant at p = .05. Children with an increase in the blood serum aflatoxin B1 lysine adduct are more likely to be stunted. These results have shown that dietary exposure to aflatoxin could lead to an increase in serum aflatoxin concentrations, both of which are associated with stunting.

Application of Probiotics in Aflatoxins Risk Reduction in Foods: A Review

Mycotoxins are known to be harmful for human and animal health, as well as the economic and trade status. Among mycotoxins, aflatoxins are the most toxic that have been classified by IARC as group 1 carcinogens. Aflatoxins could contaminate a wide range of food commodities including corn, oilseeds, spices, and ground and tree nuts as well as milk, meat, and dried fruit. Since these toxins cannot be eliminated from foods and feeds, risk assessment is performed to estimate the risk and provide the regulators with management options. So far, all risk assessments emphasize on the point that in addition to regulatory measures, aflatoxins should be decontaminated from foods and feeds. Since physical and chemical strategies have downsides, probiotics have been suggested as the best strategy to reduce the risk of aflatoxins in foods. In this article, we review the new developments in reducing the risk of aflatoxins in foods using probiotics.

Aflatoxins in Food and Feed: An Overview on Prevalence, Detection and Control Strategies.

Aflatoxins produced by the Aspergillus species are highly toxic, carcinogenic, and cause severe contamination to food sources, leading to serious health consequences. Contaminations by aflatoxins have been reported in food and feed, such as groundnuts, millet, sesame seeds, maize, wheat, rice, fig, spices and cocoa due to fungal infection during pre- and post-harvest conditions. Besides these food products, commercial products like peanut butter, cooking oil and cosmetics have also been reported to be contaminated by aflatoxins. Even a low concentration of aflatoxins is hazardous for human and livestock. The identification and quantification of aflatoxins in food and feed is a major challenge to guarantee food safety. Therefore, developing feasible, sensitive and robust analytical methods is paramount for the identification and quantification of aflatoxins present in low concentrations in food and feed. There are various chromatographic and sensor-based methods used for the detection of aflatoxins. The current review provides insight into the sources of contamination, occurrence, detection techniques, and masked mycotoxin, in addition to management strategies of aflatoxins to ensure food safety and security.

An electrochemical aptasensor based on DNA-AuNPs-HRP nanoprobes and exonuclease-assisted signal amplification for detection of aflatoxin B1

It is very essential and meaningful for detection and quantitation of aflatoxin in food and agricultural commodities to establish a rapid and accurate detection method. Herein, a novel electrochemical aptasensor for sensitive and selective detection of aflatoxin B1 (AFB1) was successfully constructed. The thiolated complementary strand (cDNA) of the AFB1 aptamer (Apt) was immobilized on the surface of the glassy carbon electrode (GCE) modified with gold nanoparticles (AuNPs) through Au–S bond. Then Apt was attached on the surface of GCE via by specific base pairing. In the presence of AFB1, the Apt was detached from the electrode surface by specific recognition between the AFB1 and Apt, forming Apt-AFB1 conjugates in solution. The conjugates were digested by exonuclease I (Exo I) to trigger AFB1 recycling. Finally, DNA-AuNPs-horseradish peroxidase (DNA-AuNPs-HRP) nanoprobes was bound with cDNA on the surface of electrode by specific base pairing. HRP could catalyze the oxidation of hydroquinone (HQ) to benzoquinone (BQ) by hydrogen peroxide (H2O2) for producing a strong electrochemical signal. Under the optimized conditions, the electrochemical signals increased with increasing concentrations of AFB1 in a range from 10−3 ng mL−1 to 200 ng mL−1 with a low detection limit of 3.3 × 10−4 ng mL−1. Moreover, the aptasensor has been successfully applied for the determination of AFB1 in peanuts and corn samples and the recoveries were 88.5 %–110.2%, which would provide a novel method for the rapid detection of AFB1 in food samples.

The Most Important Methods for Reduction or Detoxification of Aflatoxins in Food and Feed Matrices

The article's abstract is no available.

Detoxification of hazelnuts by different cold plasmas and gamma irradiation treatments

Abstract The detoxification effects of cold atmospheric-pressure (AP,3000 L/h of air, 25 kHz, 655 W-1.7 min) and low-pressure (LP,air-100 W-30 min) plasmas and gamma irradiation(GMI,10 kGy-10 min) treatments on different concentrations of pure aflatoxin B1(AFB1) and AFB1 + B2 (TotAFs) as well as same toxins spiked on hazelnut were investigated. Both plasmas reduced 72–73% of AFB1 (3 ppb) spiked on hazelnuts while GMI reduced 47% of AFB1. TotAFs (6 ppb) reductions on hazelnut after both plasmas were 70–71%, which was also higher than that of GMI (15.5%). However, the reductions in pure AFB1 at 1–50 ppb and TotAFs at 1.03–51.5 ppb after GMI (97–100%) were higher than those of AP (55–75%) and LP (69–90%) plasmas. AP plasma has the potential to be an alternative to conventional detoxification methods because it is both effective on aflatoxins in foods and maintains the sensory attributes of food evaluated by a sensory panel. Industry relevance The use of plasma technology in foods for detoxification purposes is an economic alternative to conventional and other non-thermal processes as well as meeting the industry's demand for sustainable development. This study showed that different cold plasmas are capable of reducing the aflatoxins as pure forms as well as in food. The results contributed to the understanding of cold plasma detoxification effects on aflatoxins and could be a basis for a possible industrial implementation.

Frequency and levels of aflatoxin M1 in urine of children in Bogota, Colombia.

A study was conducted to investigate the frequency and levels of AFM1 and AFM2 in urine from children who attended the emergency service of a pediatric referral hospital in Bogota, Colombia. A survey on the consumption of foods likely to be a source of aflatoxins and on sociodemographic variables was conducted as well. The frequency of AFM1 in urine was found to be 41.7% with an average concentration in positive samples of 16pgmL-1 ± 10.7pgmL-1 (range > LOD-48.5pgmL-1). The presence of AFM1 in the urine was related to the consumption of cereals likely to be contaminated with AFB1, especially corn and rice. No detectable levels of AFM2 were found in any sample. The results show that children's exposure to aflatoxins in Colombia is indeed a problem and should be one of the priorities of the health authorities. Continuous monitoring of aflatoxins in foods should be carried out, in compliance with Colombian regulations, using analytical methods that allow determination and quantification of aflatoxins in different biological and non-biological matrices at trace levels.

A label-free fluorescent aptasensor for the detection of Aflatoxin B1 in food samples using AIEgens and graphene oxide

The detection of Aflatoxin B1 (AFB1) has attracted extensive attention for food safety is a worldwide public health problem. Herein, a novel, simple and label-free fluorescent aptasensor, based on quaternized tetraphenylethene salt (TPE-Z), graphene oxide (GO) and AFB1 aptamer, has been constructed to detect AFB1. In the presence of AFB1, AFB1 aptamer undergoes a conformational switch from single stranded structure to the AFB1/AFB1 aptamer complex upon target binding, which induces the release of TPE-Z/AFB1 aptamer from the surface of GO. Thus, the fluorescence of TPE-Z/AFB1 aptamer is recovered. The assay can be performed by simply mixing TPE-Z, AFB1 aptamer, the GO and the AFB1 samples with a detection limit of 0.25 ng/mL. It is highly selective against other aflatoxins in foods and its performance has been verified in food samples (corn, milk and rice) with known concentration AFB1.

A polyphasic method for the identification of aflatoxigenic Aspergilla from cashew nuts.

The invasion of food by toxigenic fungi is a threat to public health. This study aimed at enumerating the microbial profile, detection of aflatoxin producing genes and quantification of the levels of aflatoxin contamination of cashew nuts meant for human consumption. A polyphasic method of analysis using newly formulated β-Cyclodextrin Neutral Red Desiccated coconut agar (β-CDNRDCA) and Yeast Extract Sucrose agar (YES) with Thin Layer Chromatography (TLC), Polymerase Chain Reaction (PCR) and High Performance Liquid Chromatographic (HPLC) method was adopted in determining the aflatoxigenic potential of the isolates, the presence of aflatoxin biosynthetic gene (aflM, aflD, aflR, aflJ omt-A) and estimation of the total aflatoxin content of the nuts. The fungal counts ranged from 2.0 to 2.4 log10cfu/g and sixty-three fungal isolates belonging to 18 genera and 34 species were isolated. The Aspergillus spp. were the most frequently isolated (50.79%) while Trichoderma spp. (1.59%) were the least. and fluorescence production was enhanced on the newly formulated β-CDNRDCA by the aflatoxigenic species. The aflD gene was amplified in all the isolates while aflM, aflR and aflJ gene were each amplified in 77.77% of the isolates and omt-A gene in 70.37%. The aflatoxin content of the nuts ranged from 0.03 to 0.77µg/kg and were below the 4µg/kg EU recommended limit for total aflatoxins. The present work confirms that a single method of analysis may not be sufficient to screen for the presence of aflatoxins in foods, as with a combination of different methods.

EFFICIENT CONJUGATION OF AFLATOXIN B1 WITH BOVINE SERUM ALBUMIN APPLYING FOR DEVELOPMENT OF AFLATOXIN B1 QUICK TEST

Aflatoxins are secondary metabolites mostly produced by Aspergillus flavus and Aspergillus parasiticus and found in agricultural foodstuff such as maize grains, peanuts, animal feeds,... These are toxic and cancerous agents for humans and animals. Among them, aflatoxin B1 is the most consideration due to its highest toxicity and presence in samples. Several methods were developed to detect aflatoxin in food, feed and other foodstuffs such as chromatographic methods (TLC, HPTLC, HPLC), LC-MS/MS, FTIR, RIA, ELISA, SPR, electrochemical, and immunodipstick. Among them only immunodipstick method is compatible for field usage. Therefore, aim of the present study is to determine optimal condition for conjugation of aflatoxin B1 (AFB1) with bovine serum albumin (BSA) to develop a lateral flow immunoassay test strip for detection of aflatoxin B1. Optimal conditions for generating mediate compound of aflatoxin B1 – CMO was investigated: AFB1:CMO ratio of 1:2, reflux temperature of 100oC for 2 hours. Concentration of aflatoxin B1 in reaction was 0.27 µg/µl. Conjugation of AFB1 with CMO was confirmed by thin layer chromatography, HPLC and FT-IR methods. Furthermore, optimal conditions for conjugation of mediate AFB1-CMO derivative with BSA were also investigated. Ratio of AFB1-CMO with BSA was determined as 40:1 and equal to predicted theoretical ratio. Efficient conjugation conditions were 25oC for 2 hours in bicarbonate buffer pH 9.5. Generated conjugate of AFB1-BSA was successfully applied to construct a lateral flow immunoassay test strip for detection of aflatoxin B1

The detoxification of aflatoxin M1 by Lactobacillus acidophilus and Bifidobacterium spp.: A review

One of the most studied mycotoxins is Aflatoxin M1 (AFM1), which as a carcinogen should be eliminated or limited from food products especially dairy products. Among different detoxification methods of AFM1, several strains of lactic acid bacteria (LABs) (particularly Lactobacillus acidophilus and Bifidobacterium spp.) can bind Aflatoxin M1 and furthermore, eliminate them. The principal mechanism of detoxification by LABs is the physical binding to peptidoglycan and polysaccharides present in the bacterial cell wall. This paper reviews the detoxification capability of some LABs strains and the critical roles of factors affecting the binding procedures including LAB strains, optimum incubation time, and the cell concentration of LABs. Practical application This study reviewed the impact of lactic acid bacteria on detoxification of aflatoxin M1. As the high toxicity effect of aflatoxin M1 in food is proved, finding a safe method in order to remove them is crucial. Lactic acid bacterias (LABs) are vastly applied in food science and technology due to their various beneficial effects, being easy manageable and safe technique. LABs were completely efficient in the elimination of aflatoxins in food besides having no potential adverse health/toxic effects.

A monolithic column based on covalent cross-linked polymer gels for online extraction and analysis of trace aflatoxins in food sample

Aflatoxins are highly toxic mycotoxin contamination, which pose serious food safety incidents. It is very important to precisely and rapidly determine trace aflatoxins in food. In this study, we designed porous monolithic column based on covalent cross-linked polymer gels for online extraction and analysis of trace aflatoxins in food samples with complicated matrices coupled with high-performance liquid chromatography-ultraviolet detector (HPLC-UV). The prepared monolithic column showed excellent enrichment performance due to its good permeability, good reproducibility and long life span. The study of adsorption mechanism suggested that the excellent enrichment performance of this monolithic column was attributed to the multiple effect of π-π stacking interaction, hydrophobic effect and steric effect. When the online analytical method was applied for the determine of trace aflatoxins in real food samples, aflatoxins G1 and aflatoxins B1 could be actually found in one positive bean sauce sample and quantified to be 32.8 and 26.4 μg/kg, respectively. Aflatoxins G1 in one bean sample could be also found and quantified to be 25.9 μg/kg. The low detection limits of the developed method were achieved in range of 0.08-0.2 μg/kg. And the recoveries for spiked samples were in range from 76.1 to 113% with RSDs of 1.1-9.6%. The developed method was proved to be a promising method for online enrichment and analysis of trace aflatoxins in complicated food samples.

Advances in molecular and genomic research to safeguard food and feed supply from aflatoxin contamination

Worldwide recognition that aflatoxin contamination of agricultural commodities by the fungus Aspergillus flavus is a global problem has significantly benefitted from global collaboration for understanding the contaminating fungus, as well as for developing and implementing solutions against the contamination. The effort to address this serious food and feed safety issue has led to a detailed understanding of the taxonomy, ecology, physiology, genomics and evolution of A. flavus, as well as strategies to reduce or control pre-harvest aflatoxin contamination, including (1) biological control, using atoxigenic aspergilli, (2) proteomic and genomic analyses for identifying resistance factors in maize as potential breeding markers to enable development of resistant maize lines, and (3) enhancing host-resistance by bioengineering of susceptible crops, such as cotton, maize, peanut and tree nuts. A post-harvest measure to prevent the occurrence of aflatoxin contamination in storage is also an important component for reducing exposure of populations worldwide to aflatoxins in food and feed supplies. The effect of environmental changes on aflatoxin contamination levels has recently become an important aspect for study to anticipate future contamination levels. The ability of A. flavus to produce dozens of secondary metabolites, in addition to aflatoxins, has created a new avenue of research for understanding the role these metabolites play in the survival and biodiversity of this fungus. The understanding of A. flavus, the aflatoxin contamination problem, and control measures to prevent the contamination has become a unique example for an integrated approach to safeguard global food and feed safety.

Selected plant essential oils and their main active components, a promising approach to inhibit aflatoxigenic fungi and aflatoxin production in food

ABSTRACTRecent research has showed that Aspergillus flavus and Aspergillus parasiticus are aflatoxigenic species that can become very competitive in the framework of climate change. Aflatoxins show carcinogenic, mutagenic, immunotoxic and teratogenic effects on human and animals. Effective and sustainable measures to inhibit these species and aflatoxins in food are required. Origanum vulgare and Cinnamomum zeylanicum essential oils (EOs) and their major active constituents, carvacrol and cinnamaldehyde, respectively, were assayed for inhibiting these species and aflatoxin production in maize extract medium under different environmental conditions. Doses of 10–1000 mg l−1 were assayed and the effective doses for 50 (ED50) and 90% (ED90) growth inhibition were determined. The ED50 of cinnamaldehyde, carvacrol, oregano EO, and cinnamon EO against A. flavus were in the ranges 49–52.6, 98–145, 152–505, 295–560 mg l−1 and against A. parasiticus in the ranges 46–55.5, 101–175, 260–425 and 490–675 mg l−1, respectively, depending on environmental conditions. In A. flavus treatments ED90 were in the ranges 89.7–90.5, 770–860 and 820–>1000 mg l−1 for cinnamaldehyde, carvacrol and cinnamon EO, and in A. parasiticus treatments in the ranges 89–91, 855–>1000 and 900–>1000 mg l−1, respectively. ED90 values for oregano EO against both species were >1000 mg l−1. Growth rates of both species were higher at 37 than at 25°C and at 0.99 than at 0.96 aw. Aflatoxin production was higher at 25 than at 37°C. Stimulation of aflatoxin production was observed at low doses except for cinnamaldehyde treatments. The effectiveness of EOs and their main constituents to inhibit fungal growth and aflatoxin production in contact assays was lower than in vapour phase assays using bioactive EVOH-EO films previously reported.

Aflatoxins in feed

Background. Mycotoxins are toxic secondary metabolites, which are synthesized from a large number of intermediates from the primary metabolism of saprophytic molds. Aflatoxins, due to their genotoxic and carcinogenic effects, are the most important group of mycotoxins from the aspect of their impact on human and animal health. Of all known aflatoxins, AFB1 is the most frequent, with the most harmful impact on human and animal health. Scope and Approach. Due to their prevalence and toxicity, monitoring the presence of aflatoxins in the food chain is required. The scope of this paper is to provide information on the presence of aflatoxins in animal feed and in milk. This paper describes temperature increases in Europe that are contributing to the increased presence of aflatoxins in food, as well as aflatoxin prevention and protection measures. Key Findings and Conclusions. During the last decade, serious contamination of corn with aflatoxins was recorded in southern Europe. In the summer of 2012, Serbia recorded high concentrations of aflatoxins in corn and milk. Based on climate change data, it is expected that aflatoxin contamination in corn will become more frequent.

Aflatoxins in foods of animal origin

Anatoxins are produced by various types of Aspergillus spp. fungi in a wide variety of foods and feeds. Anatoxins are toxic to human and animals, acute and chronic. In humans, they can cause liver cancer, chronic hepatitis and cirrhosis. Among the four main aflatoxins (B1? B2, Gx and G2), aflatoxin Βχ (AFBi) is the most frequently found in feeds and the most toxic one. The most important aflatoxin in foods of animal origin is aflatoxin M4 (AFM4), which is the principal hydroxylated metabolite of AFB! AFM4 is mainly found in milk from lactating animals consuming feed contaminated with AFB^ Surveys carried on the occurrence of AFM4 in raw milk in various countries all over the world during the past 15 years, showed that contamination levels were low in European Union and USA, but high in certain countries of Africa, Asia and Latin America. Other global surveys on the occurrence of AFM4 in foods of animal origin (meat, eggs etch) showed that the level of the toxin is low as compared to milk and dairy products. European Union has set the maximum residual limit (MRL) for AFM4 of 0.05 μg/kg and 0.025 μg/kg in raw milk and milk powder for infants, respectively. In order to protect the consumer's health, control measures should be applied to avoid contamination of feed and foods with aflatoxins.

Current Immunoassay Methods for the Rapid Detection of Aflatoxin in Milk and Dairy Products.

The presence of mycotoxins in foodstuff causes serious health problems to consumers and economically affects the food industry. Among the mycotoxins, aflatoxins are very toxic and highly carcinogenic contaminants which affect the safety of many foods, and therefore endanger human health. Aflatoxin M1 (AFM1 ) found in milk results from the biotransformation of aflatoxin B1 . Many efforts have been made to control the source of AFM1 from farmers to dairy product companies. However, AFM1 escapes ordinary methods of food treatment such as cooking, sterilization, and freezing, hence it appears in milk and dairy products. The presence of high levels of AFM1 constitutes an alarming threat as milk and dairy products contain essential nutrients for human health, especially for infants and children. For this reason, there is a pressing need for developing a fast and reliable screening method for detecting trace aflatoxins in food. Several analytical methods based on high-performance liquid chromatography (HPLC) and mass spectroscopy have been used for aflatoxin detection; however, they are expensive, time-consuming, and require many skills. Recently, immunoassay methods, including enzyme-linked immunosorbent assay (ELISA), immunosensors, and lateral flow immunoassay (LFIA), have been preferred for food analysis because of their improved qualities such as high sensitivity, simplicity, and capability of onsite monitoring. This paper reviews the new developments and applications of immunoassays for the rapid detection of AFM1 in milk.