Aflatoxins and fumonisins in conventional and organic corn: a comprehensive review

This review analyzes the occurrence and co-exposure of aflatoxins and fumonisins in conventional and organic corn, and compares the vulnerability to contamination of both. The risks of fungal contamination in corn are real, mainly by the genera Aspergillus and Fusarium, producers of aflatoxins and fumonisins, respectively. Aflatoxins, especially AFB1, are related to a high incidence of liver cancer, and the International Agency Research of Cancer (IARC) classified them in group 1A 'carcinogenic to humans'. The occurrence in conventional corn is reported in many countries, including at higher levels than those established by legislation. IARC classified fumonisins in group 2B 'possibly carcinogenic to humans' due to their link with incidence of esophageal cancer. However, comparing corn and organic and conventional by-products from different regions, different results are observed. The co-occurrence of both mycotoxins is a worldwide problem; nevertheless, there is little data on the comparison of the co-exposure of these mycotoxins in corn and derivatives between both systems. It was found that the agricultural system is not a decisive factor in the final contamination, indicating the necessity of effective strategies to reduce contamination and co-exposure at levels that do not pose health risks.

Dietary, socioeconomic, and maize handling practices associated with aflatoxin and fumonisin exposure among women tortilla makers in 5 departments in Guatemala

Previous research has demonstrated human exposure to mycotoxins among Guatemalans, with high levels of mycotoxins being found in blood and urine samples as well as in maize for human consumption. Mishandling of crops such as maize during pre- and post-harvest has been associated with mycotoxin contamination. The overarching goal of this study was to identify risk factors for aflatoxin and fumonisin exposure in Guatemala. A cross-sectional survey of 141 women tortilla makers was conducted in the departments of Guatemala, Sololá, Suchitepéquez, Izabal, and Zacapa in February 2022. Maize and tortilla samples were collected and analyzed for aflatoxin B1 (AFB1) and fumonisin B1, B2, and B3 contamination (FB1, FB2, FB3). Urine samples were collected and analyzed for urinary FB1 (uFB1) contamination. A questionnaire was administered to collect data on sociodemographic characteristics, dietary intake of maize-based foods the week prior to the study, and maize handling practices. Descriptive statistics were used to describe common maize handling practices. A univariable analysis was conducted to identify predictors of low/high AFB1, total fumonisins, and uFB1. Multivariable logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). During tortilla processing, a reduction in the AFB1 and total fumonisin levels was observed. The presence of AFB1 in maize was associated with department and mean total fumonisin level in maize (OR: 1.705, 95% CI: 1.113-2.613). The department where the tortilleria was located was significantly associated with the presence of fumonisins in tortillas. Increased consumption of Tortrix was significantly associated with the presence of FB1 in urine (OR: 1.652, 95% CI: 1.072-2.546). Results of this study can be used in the development and implementation of supply chain management practices that mitigate mycotoxin production, reduce food waste and economic loss, and promote food security.

Abdallah M, Chen X, Rajkovic A. Current Knowledge of Individual and Combined Toxicities of Aflatoxin B1 and Fumonisin B1 In Vitro

Mycotoxins are considered the most threating natural contaminants in food. Among these mycotoxins, aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are the most prominent fungal metabolites that represent high food safety risks, due to their widespread co-occurrence in several food commodities, and their profound toxic effects on humans. Considering the ethical and more humane animal research, the 3Rs (replacement, reduction, and refinement) principle has been promoted in the last few years. Therefore, this review aims to summarize the research studies conducted up to date on the toxicological effects that AFB1 and FB1 can induce on human health, through the examination of a selected number of in vitro studies. Although the impact of both toxins, as well as their combination, were investigated in different cell lines, the majority of the work was carried out in hepatic cell lines, especially HepG2, owing to the contaminants' liver toxicity. In all the reviewed studies, AFB1 and FB1 could invoke, after short-term exposure, cell apoptosis, by inducing several pathways (oxidative stress, the mitochondrial pathway, ER stress, the Fas/FasL signaling pathway, and the TNF-α signal pathway). Among these pathways, mitochondria are the primary target of both toxins. The interaction of AFB1 and FB1, whether additive, synergistic, or antagonistic, depends to great extent on FB1/AFB1 ratio. However, it is generally manifested synergistically, via the induction of oxidative stress and mitochondria dysfunction, through the expression of the Bcl-2 family and p53 proteins. Therefore, AFB1 and FB1 mixture may enhance more in vitro toxic effects, and carry a higher significant risk factor, than the individual presence of each toxin.

Genetic Diversity of Aspergillus flavus on Maize in Guatemala

Aflatoxin contamination of maize is a leading threat to health in Guatemala. This contamination is the result of infection from Aspergillus flavus and has been effectively reduced in other countries through application of nonaflatoxigenic, indigenous strains of A. flavus. We collected 82 maize samples from throughout Guatemala in two years and isolated 272 A. flavus from these samples, including 126 unique genotypes. We provide here a phenotypic and simple sequence repeat (SSR)-based genotypic description of these isolates, as well as an analysis of the diversity of this population. High levels of genetic diversity were observed with the nonaflatoxigenic isolates in this study, but this information contributes to the development of indigenous aflatoxin biocontrol products.

A Retrospective and Prospective Cohort Study Comparing Pediatric Patients With Cleft Lip and Palate From the United States and Guatemala

Orofacial clefts (OFC) remain among the most prevalent congenital abnormalities worldwide. In the United States in 2010 to 2014, 16.2 of 10,000 live births are born with OFC compared with 23.6 of 10,000 in Alta Verapaz, Guatemala in 2012. Demographics and cleft severity scores were retrospectively gathered from 514 patients with isolated OFC at the Children's Hospital of Philadelphia scheduled for surgery from 2012 to 2019 and from 115 patients seen during surgical mission trips to Guatemala City from 2017 to 2020. Risk factors were also gathered prospectively from Guatemalan families. The Guatemalan cohort had a significantly lower prevalence of cleft palate only compared with the US cohort, which may be a result of greater cleft severity in the population or poor screening and subsequent increased mortality of untreated cleft palate. Of those with lip involvement, Guatemalan patients were significantly more likely to have complete cleft lip, associated cleft palate, and right-sided and bilateral clefts, demonstrating an increased severity of Guatemalan cleft phenotype. Primary palate and lip repair for the Guatemalan cohort occurred at a significantly older age than that of the US cohort, placing Guatemalan patients at increased risk for long-term complications such as communication difficulties. Potential OFC risk factors identified in the Guatemalan cohort included maternal cooking-fire and agricultural chemical exposure, poor prenatal vitamin intake, poverty, and risk factors related to primarily corn-based diets. OFC patients who primarily rely on surgical missions for cleft care would likely benefit from more comprehensive screening and investigation into risk factors for more severe OFC phenotypes.

Aspergillus flavus and Fusarium verticillioides and Their Main Mycotoxins: Global Distribution and Scenarios of Interactions in Maize

Maize is frequently contaminated with multiple mycotoxins, especially those produced by Aspergillus flavus and Fusarium verticillioides. As mycotoxin contamination is a critical factor that destabilizes global food safety, the current review provides an updated overview of the (co-)occurrence of A. flavus and F. verticillioides and (co-)contamination of aflatoxin B1 (AFB1) and fumonisin B1 (FB1) in maize. Furthermore, it summarizes their interactions in maize. The gathered data predict the (co-)occurrence and virulence of A. flavus and F. verticillioides would increase worldwide, especially in European cold climate countries. Studies on the interaction of both fungi regarding their growth mainly showed antagonistic interactions in vitro or in planta conditions. However, the (co-)contamination of AFB1 and FB1 has risen worldwide in the last decade. Primarily, this co-contamination increased by 32% in Europe (2010-2020 vs. 1992-2009). This implies that fungi and mycotoxins would severely threaten European-grown maize.

Presence, Co-Occurrence, and Daily Intake Estimates of Aflatoxins and Fumonisins in Maize Consumed in Food-Insecure Regions of Western Honduras

Foodborne mycotoxins are a significant food safety risk in developing countries. Our objective was to determine the occurrence of and exposure levels to aflatoxins (AFs) and fumonisins (FBs) in maize intended for human and animal consumption in food-insecure regions of western Honduras. Total AFs and FBs were quantified with a monoclonal antibody-based affinity spectrofluorimetric method. FBs were detected in 614/631 samples of maize destined for human consumption at 0.3 to 41 mg/kg (mean, 2.7 mg/kg). Of the 614 positive samples, 147 had FB levels exceeding the U.S. Food and Drug Administration (FDA) advisory threshold of 4.0 mg/kg. AFs were detected in 109/631 samples of maize for human consumption with concentrations between 1.0 and 490 µg/kg (mean, 10 µg/kg). AF levels in 34 samples exceeded the FDA regulatory limit (i.e., 20 µg/kg). The average probable daily intake of AFs in western Honduras ranged from 0 to 260 ng/kg body weight/day, and for FBs, the average probable daily intake ranged from 17 to 53 μg/kg body weight/day. AFs and FBs co-occurred in 106/631 samples with 60 samples containing both toxins at levels greater than the FDA regulatory levels. Samples of maize intended for animal feed had significantly higher AF (mean, 22 µg/kg) and FB (mean, 7.6 mg/kg) contamination levels than those observed in samples destined for human consumption. Thus, the maize supply chain in western Honduras is contaminated with mycotoxins at levels that pose health risks to both humans and livestock. More effective mycotoxin surveillance and implementation of effective mitigation strategies are needed to reduce mycotoxin contamination and exposure.

Mycological and Multiple Mycotoxin Surveillance of Sorghum and Pearl Millet Produced by Smallholder Farmers in Namibia

Mycological (mycotoxigenic Fusarium and aflatoxigenic Aspergillus spp.) and multiple mycotoxins [aflatoxin B₁ (AFB₁), fumonisin B (FB), deoxynivalenol and zearalenone] surveillance was conducted on raw whole grain sorghum (Sorghum bicolor) and pearl millet (Pennisetum glaucum) produced on smallholder farms, and processed products sold at open markets in northern Namibia. Fungal contamination was determined with morphological methods as well as with quantitative Real-Time PCR (qPCR). The concentrations of multiple mycotoxins in samples were determined with liquid chromatography tandem mass spectrometry. The incidence of mycotoxigenic Fusarium spp., Aspergillus flavus and A. parasiticus, as well as the concentrations of AFB₁ and FB were significantly (P < 0.001) higher in the malts as compared to the raw whole grains, with Aspergillus spp. and AFB₁ exhibiting the highest contamination (P < 0.001). None of the analysed mycotoxins were detected in the raw whole grains. Aflatoxin B₁ above the regulatory maximum level set by the European Commission was detected in sorghum (2 of 10 samples; 20%; 3-11 µg/kg) and pearl millet (6 of 11 samples; 55%; 4-14 µg/kg) malts. Low levels of FB₁ (6 of 10 samples; 60%; 15-245 µg/kg) were detected in sorghum malts and no FB was detected in pearl millet malts. Contamination possibly occurred postharvest, during storage, and/or transportation and processing. By critically monitoring the complete production process, the sources of contamination and critical control points could be identified and managed. Mycotoxin awareness and sustainable education will contribute to reducing mycotoxin contamination. This could ultimately contribute to food safety and security in northern Namibia where communities are exposed to carcinogenic mycotoxins in their staple diet.

Assessment of aflatoxin exposure, growth faltering and the gut microbiome among children in rural Guatemala: protocol for an observational prospective cohort and bioreactor simulations

INTRODUCTION

Aflatoxin B1 (AFB1) is a carcinogen produced by Aspergillus flavus and Aspergillus parasiticus which grow on maize. Given the high prevalence of child stunting (ie, impaired growth) and other nutritional disorders in low-income and middle-income countries, where maize is consumed, the role of aflatoxin exposure may be significant. Observational reports have demonstrated associations between aflatoxin exposure and impaired child growth; however, most have been cross-sectional and have not assessed seasonal variations in aflatoxin, food preparation and dynamic changes in growth. Biological mechanistic data on how aflatoxin may exert an impact on child growth is missing. This study incorporates a prospective cohort of children from rural Guatemala to assess (1) temporal associations between aflatoxin exposure and child growth and (2) possible mediation of the gut microbiome among aflatoxin exposure, inflammation and child growth.

METHODS AND ANALYSIS

We will prospectively evaluate aflatoxin exposure and height-for-age difference trajectories for 18 months in a cohort of 185 children aged 6-9 months at enrolment. We will assess aflatoxin exposure levels and biomarkers of gut and systemic inflammation. We will examine the faecal microbiome of each child and identify key species and metabolic pathways for differing AFB1 exposure levels and child growth trajectories. In parallel, we will use bioreactors, inoculated with faeces, to investigate the response of the gut microbiome to varying levels of AFB1 exposure. We will monitor key microbial metabolites and AFB1 biotransformation products to study nutrient metabolism and the impact of the gut microbiome on aflatoxin detoxification/metabolism. Finally, we will use path analysis to summarise the effect of aflatoxin exposure and the gut microbiome on child growth.

ETHICS AND DISSEMINATION

Ethics approval was obtained from Arizona State University Institutional Review Board (IRB; STUDY00016799) and Wuqu' Kawoq/Maya Health Alliance IRB (WK-2022-003). Findings will be disseminated in scientific presentations and peer-reviewed publications.

Mycotoxin-Linked Mutations and Cancer Risk: A Global Health Issue

Humans continue to be constantly exposed to mycotoxins, mainly through oral exposure (dietary), inhalation, or dermal contact. Recently, it has been of increasing interest to investigate mycotoxin-linked carcinogenicity. This systematic review was conducted to synthesize evidence of the association between mycotoxin-linked mutations and the risk of cancer, to provide an overview of the data linking exposure to different mycotoxins with human cancer risk, and to provide an update on current research on the risk of cancer associated with human exposure to mycotoxins. PRISMA guidelines were used when conducting the systematic review. PubMed, MEDLINE, and CINAHL electronic databases were comprehensively searched to extract the relevant studies published from inception to May 2022. A total of sixteen relevant studies (4907 participants) were identified and included in this review. Of these, twelve studies were from Asia, while four of the studies were conducted in Africa. The overall meta-analysis result found no significant association, although some of the studies confirmed an association between mycotoxin-linked mutations and primary liver cancer risk. Mainly, the experimental studies have shown associations between mycotoxin-linked mutations and cancer risk, and there is a need for researchers to confirm these links in epidemiological studies in order to guide public health policies and interventions.

Cross-genus inhibitory activity of polyoxins against aflatoxin production by Aspergillus parasiticus and fumonisin production by Fusarium fujikuroi

Co-exposure to aflatoxin and fumonisin is a health concern where corn is a staple food, and a method to prevent co-contamination of these mycotoxins in foods is urgently needed. Polyoxins are chitin synthase inhibitors produced by Streptomyces cacaoi var. asoensis. The aflatoxin production inhibitory activity of a commercially available polyoxin D and four polyoxins purified from polyoxin AL water-soluble powder, an agricultural chemical containing polyoxins, was tested. The five polyoxins dose-dependently inhibited aflatoxin production by Aspergillus parasiticus and the IC50 values of polyoxin A, B, D, K and L were 16, 74, 110, 9 and 280 µmol L-1, respectively. Polyoxins also inhibited fumonisin production by Fusarium fujikuroi, and the IC50 values of polyoxin B, D, K and L were 270, 42, 65 and 62 µmol L-1, respectively. Polyoxins repressed the transcription of genes encoding proteins required for aflatoxin biosynthesis in A. parasiticus and fumonisin biosynthesis in F. fujikuroi. Polyoxin K and D also inhibited conidiation in A. parasiticus and F. fujikuroi, respectively. These results suggest that a mixture of polyoxins may effectively prevent co-contamination of aflatoxin and fumonisin in foods.

Associations between aflatoxin B 1 ‐albumin adduct levels with metabolic conditions in Guatemala: A cross‐sectional study

Background and Aims

Metabolic conditions such as obesity, type 2 diabetes, metabolic syndrome, and nonalcoholic fatty liver disease (NAFLD) are highly prevalent in Guatemala and increase the risk for a number of disorders, including hepatocellular carcinoma (HCC). Aflatoxin B₁ (AFB₁) levels are also notably elevated in the population and are known to be associated with HCC risk. Whether AFB₁ also contributes to the high prevalence of the metabolic disorders has not been previously examined. Therefore, the purpose of this study was to assess the association between AFB₁ and the metabolic conditions.

Methods

Four‐hundred twenty‐three individuals were included in the study, in which AFB₁‐albumin adduct levels were measured in sera. Metabolic conditions included diabetes, obesity, central obesity, metabolic syndrome, and NAFLD. Crude and adjusted prevalence odds ratios (PORs) and 95% confidence intervals (95% CI) were estimated for the associations between the metabolic conditions and AFB₁‐albumin adduct levels categorized into quartiles.

Results

The study found a significant association between AFB₁‐albumin adduct levels and diabetes (Q4 vs Q1 POR = 3.74, 95%CI: 1.71‐8.19; P‐trend .003). No associations were observed between AFB₁‐albumin adduct levels and the other conditions.

Conclusions

As diabetes is the metabolic condition most consistently linked to HCC, the possible association between AFB₁ exposure and diabetes may be of public health importance. Further studies are warranted to replicate the findings and examine potential mechanisms.

Dietary and socioeconomic risk factors for fumonisin exposure among women of reproductive age in 18 municipalities in Guatemala from 2013 to 2014

Fumonisin exposure is common in populations where maize is a dietary staple, such as in Guatemala, and has been associated with negative health outcomes including neural tube defects. The objective of this study was to estimate fumonisin B1 (FB1) exposure among Guatemalan reproductive-age women and develop a better understanding of the dietary and sociodemographic risk factors for exposure. A cross-sectional study in 18 municipalities in Guatemala was conducted. Midwives and study nurses enrolled consenting women and collected individual and household demographic and socioeconomic data. A food frequency questionnaire was administered to estimate quantity and types of food products consumed. A urine sample was collected and urinary fumonisin B1 (uFB1) concentration was measured. A univariable analysis was conducted to identify predictors of low/high uFB1. Multivariable logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). In total, 775 women had analyzable urine samples. Higher uFB1 levels were associated with speaking Mayan (OR = 2.33, 95% CI:1.44-3.77), less than high school education (OR = 1.61, 95% CI:1.12-2.30), increasing dietary proportion of maize-based foods (OR = 1.02, 95% CI:1.01-1.03), and consumption of tostadas (fried tortillas) (OR = 1.11, 95% CI:1.02-1.22). Lower uFB1 levels were associated with consumption of highly processed maize-based foods (OR = 0.93, 95% CI:0.87-0.99). Tortillas were the most frequently consumed maize-based food among study participants and significantly associated with high uFB1 exposure in the univariable but not multivariable analysis. Consumption of >4,750 grams/week of maize-based foods, >5,184 g/week of locally produced maize-based foods, and >110 servings/week of tortillas were also significantly associated with high uFB1 exposure in univariable analysis. Populations with low socioeconomic status/education levels and high consumption of maize-based foods had higher fumonisin exposure. Interventions aimed at reducing the risk of exposure to mycotoxins through maize in Guatemala, including the increased consumption of non-maize-based foods, should be further explored.

Evaluation of the impact of pre- and post-harvest maize handling practices on mycotoxin contamination on smallholder farms in Guatemala

Mycotoxins are secondary metabolites produced by fungi including Aspergillus and Fusarium that commonly contaminate crops, such as maize, resulting in economic losses and food insecurity. Mycotoxins can contaminate crops during pre- and post-harvest stages. Consumption of mycotoxin-contaminated foods has been linked to a variety of negative health outcomes including liver cancer, stunting, and neural tube defects. In countries such as Guatemala where maize constitutes a major portion of the diet, mycotoxins can be a significant contributor to disease burden. This review describes maize pre- and post-harvest practices in Guatemala that can lead to the development of mycotoxins and subsequent exposure to humans and animals, current information gaps, and opportunities for future research. There are specific challenges to minimising fungal growth and subsequent mycotoxin production during storage of maize in Guatemala, including reducing moisture content, minimising pest damage, and controlling temperature. Research on maize-handling practices that are associated with the greatest mycotoxin exposure in Guatemala is needed to prioritise allocation of resources and reduce exposure.

Evaluation of aflatoxin and fumonisin co-exposure in urine samples from healthy volunteers in northern Mexico

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High frequency of co-exposure to aflatoxin and fumonisin is present in Mexicans.

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No co-exposed participants had higher concentrations of either AF or FB than co-exposed.

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Detection of aflatoxins and fumonisins in maize based foods in Mexico is common.

Aflatoxins (AF) and fumonisins (FB) are common contaminants of maize and have been associated with cancer, immune suppression, and growth stunting. In this work, AFM₁ and FB₁ were measured in urine samples of healthy volunteers from the metropolitan area of Monterrey, Mexico, while AF and FB were detected in foods collected near the sampling zone. Urine samples from 106 adults were analyzed using ultra-performance liquid chromatography-tandem mass spectrometry and toxins in foods were measured by fluorometry. The mean value of AFM₁ and FB₁ was 4.3 pg/mg creatinine from 76 samples (72 %), and 50 pg/mg creatinine from 75 samples (71 %), respectively. More than half of the samples (n = 56, 53 %) had detectable levels of both AFM₁ and FB₁. No differences in toxin levels were found between males and females or between age groups, but AFM₁ and FB₁ levels were higher (p < 0.01) when detected as a single exposure compared to co-exposed. Some significant results were found when comparing AFM₁ and FB₁ levels among groups of people assigned to levels of food consumption. Food samples had average concentrations of 5.3 μg/kg for AF and 800 μg/kg for FB. The results showed that co-exposure to AF and FB is common in the metropolitan area of Monterrey.

Aflatoxin contamination in maize: occurrence and health implications in Latin America

According to the United Nations Food and Agriculture Organisation, mycotoxicoses constitute the second most pressing food safety problem worldwide, with most cases occurring in developing countries. Maize (Zea mays L.), the main staple for many Latin Americans, is one of the best suitable substrates for mycotoxigenic Aspergillus fungi. Aflatoxins (AFs) produced primarily by Aspergillus flavus, are of significant concern, especially in developing countries. While AFs production occurs mainly in warmer, tropical, and subtropical environments, recent evidence suggests that global climate change favours their presence in regions with little or no awareness of this issue. AFs interfere with metabolic processes, causing cancer and other health disorders resulting in health hazards and even death. The setting of national acceptable regulatory levels of AFs is necessary for Latin American countries. Unfortunately, no estimates of the economic impact of AFs in this region are currently available nor the cost of regulatory programs designed to reduce health risks to animals and humans. This review explores relevant data about incidence of AFs in maize produced in the region and the adverse effects of the consumption of contaminated foods and the associated health consequences for Latin American consumers. Regulations aimed to mitigate AFs exposure to consumers are also reviewed and identified gaps for researchers and actors of the maize value chain are also proposed.

Foreword – special issue Mycotoxins in Latin America

Latin America with its considerable North-South extent is subject to climate that varies from tropical, subtropical and warm temperate to temperate. Different agricultural products are produced in the area including cereals, oilseeds, beans, fruits and nuts together with animal production including cattle for beef and milk, pigs, poultry and fish. The heterogeneity of agriculture in Latin America is reflected in the diversity of the region’s farm structures. While agriculture in the Southern Cone is dominated by large, commercial and export-oriented farms, particularly in Argentina and Brazil, besides increasingly in other countries like Uruguay, much of the rest of the region is characterised by smallholder and family agriculture. The contamination of agricultural products with mycotoxins has impact both human and animal health, as well as the economy due to losses related to rejections of agricultural products and by-products during trade. The economic burden related to the consumption of mycotoxins by animals is especially important, causing productivity losses up to the death of animals. The relevant mycotoxins are fumonisins, deoxynivalenol (DON) and zearalenone (ZEN) in cereals and cereal-based products, aflatoxins in cereals, oily seeds and nuts, aflatoxin M1 in milk and dairy products as well as ochratoxin A (OTA) in coffee, grapes and raisins. Co-occurrence of mycotoxins has also been observed mainly with aflatoxins and fumonisins in different Latin American countries (Torres et al., 2015). Advances on legislation in different countries including Argentina, Brazil, Chile, Mexico and Uruguay have been done to establish maximum limits for mycotoxins including aflatoxins, DON, ZEN, OTA, patulin and ergot alkaloids (ANVISA, 2011/2017; CAA, 2019/2021, Norma Oficial Mexicana, N.-243-S., 2010/2010; Reglamento Sanitario de los Alimentos, 2013).

Aflatoxin B1 exposure and liver cirrhosis in Guatemala: a case-control study

Objective

In Guatemala, cirrhosis is among the 10 leading causes of death, and mortality rates have increased lately. The reasons for this heavy burden of disease are not clear as the prevalence of prominent risk factors, such as hepatitis B virus, hepatitis C virus and heavy alcohol consumption, appears to be low. Aflatoxin B₁ (AFB₁) exposure, however, appears to be high, and thus could be associated with the high burden of cirrhosis. Whether AFB₁ increases the risk of cirrhosis in the absence of viral infection, however, is not clear.

Design

Cirrhosis cases (n=100) from two major referral hospitals in Guatemala City were compared with controls (n=200) from a cross-sectional study. Logistic regression was used to estimate the ORs and 95% CIs of cirrhosis and quintiles of AFB₁ in crude and adjusted models. A sex-stratified analysis was also conducted.

Results

The median AFB₁ level was significantly higher among the cases (11.4 pg/mg) than controls (5.11 pg/mg). In logistic regression analyses, higher levels of AFB₁ was associated with cirrhosis (quintile 5 vs quintile 1, OR: 11.55; 95% CI 4.05 to 32.89). No attenuation was observed with adjustment by sex, ethnicity, hepatitis B virus status, and heavy alcohol consumption. A significantly increasing trend in association was observed in both models (p trend <0.01). Additionally, the cirrhosis–AFB₁ association was more prominent among men.

Conclusions

The current study found a significant positive association between AFB₁ exposure and cirrhosis. Mitigation of AFB₁ exposure and a better understanding of additional risk factors may be important to reduce the burden of cirrhosis in Guatemala.

A review of Environmental risks and vulnerability factors of indigenous populations from Latin America and the Caribbean in the face of the COVID-19

Latin America and the Caribbean (LAC) was declared a new epicentre of the coronavirus pandemic by the World Health Organization (WHO) on 22 May 2020. As of 13 January 2021, the numbers of deaths and cases caused by COVID-19 in LAC reported are 552,000 and 17'485,000 respectively. LAC concentrates the largest percentage of indigenous populations throughout the world. In this region, poverty is persistent and particularly rural indigenous peoples hold the steepest barriers to health services and experience profound discrimination based on ethnicity, poverty, and language, compared to their non-indigenous counterparts. The information regarding the health of indigenous populations, in general, is scarce, and this problem is aggravated in the face of the COVID-19 pandemic. Therefore, the main objective of this work is to address the overall scenario of indigenous peoples in the Latin American and Caribbean region from March 2020 to January 2021, in this manner gathering information regarding health problems, economic, social, cultural and environmental factors that make indigenous populations in LAC particularly vulnerable to serious health effects from the COVID-19 pandemic, as well as compiling the mitigation strategies implemented in indigenous communities.

Aflatoxin Exposure Among Mothers and Their Infants from the Western Highlands of Guatemala

OBJECTIVES

We examined breast milk of mothers and urine of infants before and after introduction of supplementary foods for aflatoxin M₁ (AFM₁) and the association between AFM₁ with maternal and infant diet.

METHODS

A prospective cohort study was conducted among mothers and infants ages 0-6 months and 7-12 months from June-October 2014. Sociodemographic, dietary, birth, and health data were collected. A breast milk sample was collected from each mother and a urine sample from each infant at baseline (time point 1) and monthly for 2 time points thereafter; samples collected at baseline and time point 3 were tested for AFM₁.

RESULTS

Almost 5% of breast milk and 15.7% of urine samples tested AFM₁-positive. The median AFM₁ in breast milk was 0.020 ng/mL and in urine 0.077 ng/mg creatinine. At time point 3, infants of 5 of the 6 mothers in each group who were AFM₁-positive in breast milk were also AFM₁-positive in urine. Mothers' consumption of cooked maize/maize dough ≥ 3 days per week (OR 2.96, 95% CI = 1.19-7.34) and mothers' consumption of tamales made from maize ≥ 3 days per week (OR 0.28, 95% CI = 0.10-0.73) were significantly associated with AFM₁ in infant urine.

CONCLUSION

This is the first study in Guatemala documenting aflatoxin exposure in both breast milk of lactating mothers and infants´ urine during the first year of life. This may have important implications in understanding the multicausality of the high rates of stunting among children < 5 years old in Guatemala.

Aflatoxin and the Etiology of Liver Cancer and Its Implications for Guatemala

During the 60 years since the first scientific reports about a relation between aflatoxin exposure and adverse health consequences, both in animals and humans, there has been a remarkable number of basic, clinical and population science studies characterizing the impact of this mycotoxin on diseases such as liver cancer. Many of these human investigations to date have focused on populations residing in Asia and Africa due to the high incidence of liver cancer and high exposures to aflatoxin. These studies formed the basis for the International Agency for Research on Cancer to classify the aflatoxins as Group 1 known human carcinogens. In addition, aflatoxin contamination levels have been used in international commodity trade to set the price of various staples such as maize and groundnuts. While there have been many case-control and prospective cohort studies of liver cancer risk over the years there have been remarkably few investigations focused on liver cancer in Latin America. Our interdisciplinary and multiple institutional collaborative has been developing a long-term strategy to characterize the role of aflatoxin and other mycotoxins as health risk factors in Guatemala and neighboring countries. This paper summarizes a number of the investigations to date and provides a roadmap of our strategies for the near term to discern the emergent etiology of liver cancer in this region. With these data in hand public health-based prevention strategies could be strategically implemented and conducted to lower the impact of these mycotoxins on human health.

A Recent Overview of Producers and Important Dietary Sources of Aflatoxins

Aflatoxins (AFs) are some of the most agriculturally important and harmful mycotoxins. At least 20 AFs have been identified to this date. Aflatoxin B1 (AFB1), the most potent fungal toxin, can cause toxicity in many species, including humans. AFs are produced by 22 species of Aspergillus section Flavi, 4 species of A. section Nidulantes, and 2 species of A. section Ochraceorosei. The most important and well-known AF-producing species of section Flavi are Aspergillus flavus, A. parasiticus, and A. nomius. AFs contaminate a wide range of crops (mainly groundnuts, pistachio nuts, dried figs, hazelnuts, spices, almonds, rice, melon seeds, Brazil nuts, and maize). Foods of animal origin (milk and animal tissues) are less likely contributors to human AF exposure. Despite the efforts to mitigate the AF concentrations in foods, and thus enhance food safety, AFs continue to be present, even at high levels. AFs thus remain a current and continuously pressing problem in the world.

Aflatoxins and the traditional process of nixtamalisation in indigenous communities from the Huasteca Potosina region

Aflatoxins represent one of the biggest public health problems in food safety, due to their toxic potential for humans and animals. They can lead to serious threats, such as hepatotoxicity, teratogenicity and immunotoxicity. Maize is the most important cereal consumed in Mexico, with which tortillas, tamales, flours, toasts and other products are elaborated. The elaboration of tortillas begins with nixtamalisation, which is an ancient maize process, developed and applied by indigenous Mesoamerican population. Some studies have shown the effect of nixtamalisation in the inactivation of aflatoxins. The purpose of this research was to record the traditional nixtamalisation process (TNP) and to register the presence of the aflatoxin B1 (AFB1) in tortillas and the exposure to AFB1 in indigenous communities living in the Huasteca Potosina, in central México. To register the nixtamalisation technique, a questionnaire was given to women, to illustrate the process step by step. Digestion, extraction, purification, and identification of the adduct AFB1-lysine (AFB1-Lys) in serum were performed. The TNP was analysed by 51 surveys, 4% of the tortillas was above the maximum permissible levels, according to Mexican guidelines; however, all blood samples showed presence of AFB1. TNP done in indigenous communities in the Huasteca Potosina region is not efficient enough to eliminate aflatoxins present in contaminated maize. It is necessary to improve conditions of places in which the grain is stored and knowledge about the risk of exposure to aflatoxins in rural communities, as key steps for preventing exposure to this type of mycotoxins.

Mycotoxin exposure and human cancer risk: A systematic review of epidemiological studies

In recent years, there has been an increasing interest in investigating the carcinogenicity of mycotoxins in humans. This systematic review aims to provide an overview of data linking exposure to different mycotoxins with human cancer risk. Publications (2019 and earlier) of case-control or longitudinal cohort studies were identified in PubMed and EMBASE. These articles were then screened by independent reviewers and their quality was assessed according to the Newcastle-Ottawa scale. Animal, cross-sectional, and molecular studies satisfied criteria for exclusion. In total, 14 articles were included: 13 case-control studies and 1 longitudinal cohort study. Included articles focused on associations of mycotoxin exposure with primary liver, breast, and cervical cancer. Overall, a positive association between the consumption of aflatoxin-contaminated foods and primary liver cancer risk was verified. Two case-control studies in Africa investigated the relationship between zearalenone and its metabolites and breast cancer risk, though conflicting results were reported. Two case-control studies investigated the association between hepatocellular carcinoma and fumonisin B1 exposure, but no significant associations were observed. This systematic review incorporates several clear observations of dose-dependent associations between aflatoxins and liver cancer risk, in keeping with IARC Monograph conclusions. Only few human epidemiological studies investigated the associations between mycotoxin exposures and cancer risk. To close this gap, more in-depth research is needed to unravel evidence for other common mycotoxins, such as deoxynivalenol and ochratoxin A. The link between mycotoxin exposures and cancer risk has mainly been established in experimental studies, and needs to be confirmed in human epidemiological studies to support the evidence-based public health strategies.

The influence of local market and household factors on aflatoxin presence in maize and symptoms of its exposure to children in Guatemala

Recent evidence supports the hypothesis that aflatoxin exposure from maize can influence malnutrition rates among children. Therefore, in Guatemala we investigated two questions; which maize sources exposed households to higher risk of aflatoxin exposure symptoms and what the risk factors were for each maize source, pre- and post-maize harvest. Survey data and household maize samples were collected in October 2016 (pre-harvest) and February 2017 (post-harvest) in San Vicente, Guatemala. Structural equation modeling (SEM) and odds ratios were used to assess the data. The results suggested that households which purchased maize from the market had 3.64 higher odds of high levels of aflatoxin. The models identified that good market purchase habits were significant for market-based maize sources while improved post-harvest practices and improved types of maize storage were significant for subsistence-based maize sources. Cumulative results suggest multiple interventions may be effective but are dependent on time of year and source of maize.

Mycotoxin exposure is associated with increased risk of esophageal squamous cell carcinoma in Huaian area, China

BACKGROUND

Consumption of moldy food has previously been identified as a risk factor for esophageal squamous cell carcinoma (ESCC) in high-risk countries; however, what contributing roles these dietary carcinogenic mycotoxins play in the etiology of ESCC are largely unknown.

METHODS

A mycotoxin biomarker-incorporated, population-based case-control study was performed in Huaian area, Jiangsu Province, one of the two high-risk areas in China. Exposure biomarkers of aflatoxins (AF) and fumonisins (FN) were quantitatively analyzed using HPLC-fluorescence techniques.

RESULTS

Among the cases (n = 190), the median levels of AF biomarker, serum AFB1-lysine adduct, and FN biomarker, urinary FB1, were 1.77 pg/mg albumin and 176.13 pg/mg creatinine, respectively. Among the controls (n = 380), the median levels of AFB1-lysine adduct and urinary FB1 were 1.49 pg/mg albumin and 56.92 pg/mg creatinine, respectively. These mycotoxin exposure biomarker levels were significantly higher in cases as compared to controls (p <  0.05 and 0.01, respectively). An increased risk to ESCC was associated with exposure to both AFB1 and FB1 (p <  0.001 for both).

CONCLUSIONS

Mycotoxin exposure, especially to AFB1 and FB1, was associated with the risk of ESCC, and a greater-than-additive interaction between co-exposures to these two mycotoxins may contribute to the increased risk of ESCC in Huaian area, China.

Aflatoxin B1 in nixtamalized maize in Mexico; occurrence and accompanying risk assessment

Maize is a staple food in Mexico that might contain Aflatoxin B1 (AFB1). Nonetheless, data on the exposure and risk assessment of AFB1 from maize for the Mexican population are limited. The aim of the present study was to analyse the occurrence of AFB1 in Mexican nixtamalized maize samples, and to assess the accompanying exposure and risk. Four out of 88 samples contained AFB1 at levels above the limit of detection (1 ng/g). AFB1 occurrence values obtained in this study and additional occurrence values from literature were combined with available literature data for mean and P95 consumption of maize based products. For a 70 kg body weight person, lower bound and upper bound exposure assessments resulted in estimated daily intakes (EDI) of 0.7-8.5 ng/kg bw/day, based on a mean maize consumption. Based on the P95 maize consumption these EDI values amounted to 3.3-11.7 ng/kg bw/day. The corresponding Margin of Exposure (MOE) values amounted to 257-20 for the mean and 50-15 for the P95 consumers. The estimated increased cancer risks were 9-320 and 43-439 cases/106 individuals/lifetime of 75 years for the mean and P95 consumers, respectively. Altogether, the assessment reveals the need for continued risk management of AFB1 in Mexico.

Changing trends in liver cancer incidence by race/ethnicity and sex in the US: 1992-2016

PURPOSE

Liver cancer incidence continues to increase while incidence of most other cancers is decreasing. We analyze recent and long-term trends of US liver cancer incidence by race/ethnicity and sex to best understand where to focus preventive efforts.

METHODS

Liver cancer incidence rates from 1992 to 2016 were obtained from the Surveillance, Epidemiology, and End Results registry. Delay-adjusted age-standardized incidence trends by race/ethnicity and sex were analyzed using joinpoint regression. Age-specific incidence was analyzed using age-period-cohort models. Hepatitis C seroprevalence by cohort was calculated using National Health and Nutrition Examination Survey data.

RESULTS

Liver cancer incidence has peaked in males and Asian or Pacific Islanders. Hispanic males, a high-incidence population, are experiencing a decrease in incidence, although not yet statistically significant. In contrast, incidence continues to increase in females, although at lower rates than in the 1990s, and American Indian/Alaska Natives (AI/ANs). Liver cancer incidence continues to be higher in males. Non-Hispanic Whites have the lowest incidence among racial/ethnic groups. Trends largely reflect differences in incidence by birth-cohort, which increased considerably, particularly in males, for those born around the 1950s, and continues to increase in females and AI/ANs. The patterns in males are likely driven by cohort variations in Hepatitis C infection.

CONCLUSIONS

Liver cancer incidence appears to have peaked among males. However, important differences in liver cancer trends by race/ethnicity and sex remain, highlighting the need for monitoring trends across different groups. Preventive interventions should focus on existing liver cancer disparities, targeting AI/ANs, females, and high-incidence groups.

Association between aflatoxin-albumin adduct levels and tortilla consumption in Guatemalan adults

Aflatoxin B₁ (AFB₁) is a known human hepatocarcinogen and a recent study reported elevated AFB₁ levels, measured by serum albumin biomarkers, among Guatemalan adults. While AFB₁ can contaminate a variety of foodstuffs, including maize, Guatemala's main dietary staple, the relationship of maize intake to serum AFB₁-albumin adducts levels in Guatemala has not been previously examined. As a result, a cross-sectional study was conducted among 461 Guatemalan adults living in five geographically distinct departments of the country. Participants provided a serum sample and completed a semi-quantitative food frequency questionnaire and a sociodemographic questionnaire. Multiple linear regression analysis was used to estimate the least square means (LSQ) and 95% confidence intervals (95% CI) of log-transformed AFB₁-albumin adducts by quintiles of maize consumption in crude and adjusted models. Additionally, analyses of tortilla consumption and levels of maize processing were conducted. The median maize intake was 344.3 g per day [Interquartile Range (IQR): 252.2, 500.8], and the median serum AFB₁-albumin adduct level was 8.4 pg/mg albumin (IQR: 3.8, 22.3). In adjusted analyses, there was no association between overall maize consumption and serum AFB₁-albumin levels. However, there was a statistically significant association between tortilla consumption and AFB₁-albumin levels (p_trend = 0.01). The LSM of AFB₁-albumin was higher in the highest quintile of tortilla consumption compared to the lowest quintile [LSM:9.03 95%CI: 7.03,11.70 vs 6.23, 95%CI: 4.95,8.17, respectively]. These findings indicate that tortilla may be an important source of AFB₁ exposure in the Guatemalan population. Therefore, efforts to control or mitigate AFB₁ levels in contaminated maize used for tortillas may reduce overall exposure in this population.

Mycotoxin Contamination of Beverages Obtained from Tropical Crops

This review is mainly centered on beverages obtained from tropical crops, including tea, nut milk, coffee, cocoa, and those prepared from fruits. After considering the epidemiological data found on the matrices above, the focus was given to recent methodological approaches to assess the most relevant mycotoxins. Aspects such as singularities among the mycotoxin and the beverage in which their were found, and the economic effects and repercussions that the mycotoxin-tainted ingredients have on the beverage industry were pointed out. Finally, the burden of their consumption through beverages, including risk and health effects on humans, was addressed as well.

Fumonisins and their analogues in contaminated corn and its processed foods - a review

One of the food security problems faced worldwide is the occurrence of mycotoxins in grains and their foods. Fumonisins (FBs) are mycotoxins which are prevalent in corn (Zea mays L.) and its based foods. Their intake and exposure have been epidemiologically and inconclusively associated with oesophageal cancer and neural tube defects in humans, and other harmful health effects in animals. The toxic effects of FBs can be acute or chronic and these metabolites bioaccumulate mainly in liver and kidney tissues. Among FBs, fumonisin B₁ (FB₁) is the most relevant moiety although the 'hidden' forms produced after food thermal processes are becoming relevant. Corn is the grain most susceptible to Fusarium and FBs contamination and the mould growth is affected both by abiotic and biotic factors during grain maturation and storage. Mould counts are mainly affected by the grain water activity, the environmental temperature during grain maturation and insect damage. The abiotic factors affected by climatic change patterns have increased their incidence in other regions of the world. Among FBs, the hidden forms are the most difficult to detect and quantify. Single or combined physical, chemical and biological methods are emerging to significantly reduce FBs in processed foods and therefore diminish their toxicological effects.

Assessing the combined toxicity of the natural toxins, aflatoxin B1, fumonisin B1 and microcystin-LR by high content analysis

As human co-exposure to natural toxins through food and water is inevitable, risk assessments to safeguard health are necessary. Aflatoxin B₁ and fumonisin B₁, frequent co-contaminants of maize and microcystin-LR, produced in freshwater by cyanobacteria are all naturally occurring potent toxins that threaten human health. Populations in the poorest regions of the world may suffer repeated simultaneous exposure to these contaminants. Using High Content Analysis, multiple cytotoxicity endpoints were measured for the individual toxins and mixtures in various cell lines. Results highlighted that significant cytotoxic effects were observed for aflatoxin B₁ in all cell lines while no cytotoxic effects were observed for fumonisin B1 or microcystin-LR. Aflatoxin B₁/microcystin-LR was cytotoxic in the order HepG2 > Caco-2 > MDBK. Fumonisin B₁/microcystin-LR affected MDBK cells. The ternary mixture was cytotoxic to all cell lines. Most combinations were additive, however antagonism was observed for binary and ternary mixtures in HepG2 and MDBK cell lines at low and high concentrations. Synergy was observed in all cell lines, including at low concentrations. The combination of these natural toxins may pose a significant risk to populations in less developed countries. Furthermore, the study highlights the complexity around trying to regulate for human exposure to multiple contaminants.

Association of aflatoxin exposure and height-for-age among young children in Guatemala

Aflatoxin exposure has been proposed to affect child height-for-age. The following hypothesized associations were tested in Guatemala: (1) aflatoxin (B₁, B₂, G₁, G₂) exposure and environmental enteric dysfunction (EED) and child height-for-age z-score; and (2) aflatoxin exposures and subsequent symptoms of aflatoxins. Maize consumption data, health data, and samples of maize from households were collected from mothers and their children - under five - in October 2016 (n = 320) and February 2017 (n = 120). Maize samples were tested for aflatoxin levels and maize consumption data were used to compute an aflatoxin exposure level. Results suggest that there was a significant negative correlation between the putative aflatoxin exposure level and child height-for-age z-score (-0.073, p = 0.030), but not for EED. Furthermore, aflatoxin exposure was significantly correlated with aflatoxin symptoms only at the same time point (0.123, p = 0.026). These results support the potential need for engineered solutions to household aflatoxin transmission problems in rural communities of Guatemala.

Safety and Quality Assessment of Smallholder Farmers' Maize in the Western Highlands of Guatemala

Maize ( Zea mays) is a staple in many developing countries but is known to be prone to pest (insects, birds, and rodents) and fungal infestation. In Guatemala, mycotoxin contamination of cultivated products may occur owing to such factors as environmental conditions and the use of traditional agriculture operations. To assess the current maize conditions in Guatemala, a small-scale study was performed. Mold and insect counts and mycotoxin (aflatoxin and fumonisin) concentrations were determined on 25 farms in two townships (Chiantla and Todos Santos) of the Huehuetenango Department. Total fungal counts were 3.6 to 6.83 log CFU/g with no significant differences ( P > 0.05) across farms at different altitudes. Farms where maize was not produced but was purchased were at higher risk of fumonisin contamination, whereas local producers were mostly affected by aflatoxins. Aflatoxin was present in maize from 100% of farms at 1.0 to 85.3 ppb, and fumonisin was detected on 52% of farms at 0.4 to 31.0 ppm. Average mycotoxin consumption amounts were above the recommended maximum intake for aflatoxin in both produced and purchased maize and above the provisional maximum tolerable daily intake for fumonisin in purchased maize. Estimated daily intake was 0.01 to 0.85 μg/kg of body weight per day for aflatoxin and 2.9 to 310.0 μg/kg of body weight per day for fumonisin. An entomological analysis revealed overall 32% prevalence of Ephestia kuehniella (flour moth), 16% prevalence of Sitophilus zeamais (maize weevil), and 8% prevalence of Tribolium sp. (flour beetle) on the analyzed farms. This study highlighted poor agricultural practices used in the highlands of Guatemala. Current practices should be revised for the production of maize that is safe for consumption by the population in this region.

The Mycotox Charter: Increasing Awareness of, and Concerted Action for, Minimizing Mycotoxin Exposure Worldwide

Mycotoxins are major food contaminants affecting global food security, especially in low and middle-income countries. The European Union (EU) funded project, MycoKey, focuses on “Integrated and innovative key actions for mycotoxin management in the food and feed chains” and the right to safe food through mycotoxin management strategies and regulation, which are fundamental to minimizing the unequal access to safe and sufficient food worldwide. As part of the MycoKey project, a Mycotoxin Charter (charter.mycokey.eu) was launched to share the need for global harmonization of mycotoxin legislation and policies and to minimize human and animal exposure worldwide, with particular attention to less developed countries that lack effective legislation. This document is in response to a demand that has built through previous European Framework Projects—MycoGlobe and MycoRed—in the previous decade to control and reduce mycotoxin contamination worldwide. All suppliers, participants and beneficiaries of the food supply chain, for example, farmers, consumers, stakeholders, researchers, members of civil society and government and so forth, are invited to sign this charter and to support this initiative.

Aflatoxin and viral hepatitis exposures in Guatemala: Molecular biomarkers reveal a unique profile of risk factors in a region of high liver cancer incidence

Liver cancer is an emerging global health issue, with rising incidence in both the United States and the economically developing world. Although Guatemala experiences the highest rates of this disease in the Western hemisphere and a unique 1:1 distribution in men and women, few studies have focused on this population. Thus, we determined the prevalence and correlates of aflatoxin B₁ (AFB₁) exposure and hepatitis virus infection in Guatemalan adults. Healthy men and women aged ≥40 years (n = 461), residing in five departments of Guatemala, were enrolled in a cross-sectional study from May—October of 2016. Serum AFB₁-albumin adducts were quantified using isotope dilution mass spectrometry. Multivariate linear regression was used to assess relationships between AFB₁-albumin adduct levels and demographic factors. Biomarkers of hepatitis B virus and hepatitis C virus infection were assessed by immunoassay and analyzed by Fisher’s exact test. AFB₁-albumin adducts were detected in 100% of participants, with a median of 8.4 pg/mg albumin (range, 0.2–814.8). Exposure was significantly higher (p<0.05) in male, rural, low-income, and less-educated participants than in female, urban, and higher socioeconomic status participants. Hepatitis B and C seropositivity was low (0.9% and 0.5%, respectively). Substantial AFB₁ exposure exists in Guatemalan adults, concurrent with low prevalence of hepatitis virus seropositivity. Quantitatively, AFB₁ exposures are similar to those previously found to increase risk for liver cancer in Asia and Africa. Mitigation of AFB₁ exposure may reduce liver cancer incidence and mortality in Guatemala, warranting further investigation.

Sequential dietary exposure to aflatoxin B1 and fumonisin B1 in F344 rats increases liver preneoplastic changes indicative of a synergistic interaction

Dietary co-exposure to aflatoxin B1 (AFB1) and fumonisin B1 (FB1) and their interaction on hepatocellular carcinogenesis is of particular concern in toxicology and public health. In this study we evaluated the liver preneoplastic effects of single and sequential dietary exposure to AFB1 and FB1 in the F344 rat carcinogenesis model. Serum biochemical alterations, liver histopathological changes, and the formation of liver glutathione S transferase positive (GST-P+) foci were the major outcome parameters examined. Compared to the AFB1-only treatment, the FB1-only treatment induced less dysplasia, and more apoptosis and mitoses. Sequential AFB1 and FB1 treatment lead to increased numbers of dysplasia, apoptosis and foci of altered hepatocytes, as compared to either mycotoxin treatment alone. More importantly, sequential exposure to AFB1 and FB1 synergistically increased the numbers of liver GTP-P+ foci by approximately 7.3-and 12.9-fold and increased the mean sizes of GST-P+ foci by 6- and 7.5-fold, respectively, as compared to AFB1- or FB1-only treatment groups. In addition, liver ALT and AST levels were significantly increased after sequential treatment as compared to single treatment groups. The results demonstrate the interactive effect of dietary AFB1 and FB1 in inducing liver GST-P+ foci formation and provide information to model future intervention studies.

Fusarium Toxins in Cereals: Occurrence, Legislation, Factors Promoting the Appearance and Their Management

Fusarium diseases of small grain cereals and maize cause significant yield losses worldwide. Fusarium infections result in reduced grain yield and contamination with mycotoxins, some of which have a notable impact on human and animal health. Regulations on maximum limits have been established in various countries to protect consumers from the harmful effects of these mycotoxins. Several factors are involved in Fusarium disease and mycotoxin occurrence and among them environmental factors and the agronomic practices have been shown to deeply affect mycotoxin contamination in the field. In the present review particular emphasis will be placed on how environmental conditions and stress factors for the crops can affect Fusarium infection and mycotoxin production, with the aim to provide useful knowledge to develop strategies to prevent mycotoxin accumulation in cereals.

An in vitro study of alkaline phosphatase sensitivity to mixture of aflatoxin B1 and fumonisin B1 in the hepatopancreas of coastal lagoon wild and farmed shrimp Litopenaeus vannamei

This study aimed to establish the combined effect of aflatoxin B1 (AFB1) and fumonisin B1 (FB1) on wild Litopenaeus vannamei hepatopancreas alkaline phosphatase (AP) activity compared with that of farmed shrimp. AP activity in hepatopancreas extract was confirmed by several specific inhibitor assays. AP activity of wild shrimp was higher than that of farmed shrimp (p < 0.05). However, AP activity from both wild and farmed shrimp was inhibited when incubated with AFB1 and FB1. The greatest inhibition occurred when AP was incubated with a mixture of AFB1 and FB1. The IC50 for AFB1 on AP activity of wild and farmed shrimp hepatopancreases was 0.790 and 0.398 μg/mL, respectively. The IC50 of FB1 was 0.87 μg/mL for wild shrimp and 0.69 μg/mL for farmed shrimp. These results suggest that, at the mycotoxins concentrations used in the study, AP from farmed L. vannamei was sensitive to the presence of both mycotoxins; however, AP is more sensitive to the combination of AFB1 + FB1 suggesting a possible synergistic or potentiating inhibitory effect.