Risk Of Aflatoxin Contamination Research Articles

An improved simulation model to predict pre-harvest aflatoxin risk in maize

Aflatoxin is a potent carcinogen produced by Aspergillus flavus, which frequently contaminates maize (Zea mays L.) in the field between 40° north and 40° south latitudes. A mechanistic model to predict risk of pre-harvest contamination could assist in management of this very harmful mycotoxin. In this study we describe an aflatoxin risk prediction model which is integrated with the Agricultural Production Systems Simulator (APSIM) modelling framework. The model computes a temperature function for A. flavus growth and aflatoxin production using a set of three cardinal temperatures determined in the laboratory using culture medium and intact grains. These cardinal temperatures were 11.5°C as base, 32.5°C as optimum and 42.5°C as maximum. The model used a low (≤0.2) crop water supply to demand ratio—an index of drought during the grain filling stage to simulate maize crop's susceptibility to A. flavus growth and aflatoxin production. When this low threshold of the index was reached the model converted the temperature function into an aflatoxin risk index (ARI) to represent the risk of aflatoxin contamination. The model was applied to simulate ARI for two commercial maize hybrids, H513 and H614D, grown in five multi-location field trials in Kenya using site specific agronomy, weather and soil parameters. The observed mean aflatoxin contamination in these trials varied from <1 to 7143ppb. ARI simulated by the model explained 99% of the variation (p≤0.001) in a linear relationship with the mean observed aflatoxin contamination. The strong relationship between ARI and aflatoxin contamination suggests that the model could be applied to map risk prone areas and to monitor in-season risk for genotypes and soils parameterized for APSIM.

Exposure of children 4 to 6 months of age to aflatoxin in Kisumu County, Kenya

Contamination of foods by aflatoxins is a global health problem in both developed and developing countries. Exposure to the toxin s is associated with a range of effects on health including stunting in children. Commodities at high risk of aflatoxin contamination include cereals, legumes, milk, fish and meats. Children are more vulnerable to effects of aflatoxin exposure compared to adults. Being genotoxic , levels of aflatoxins in foods should be kept as low as possible, given that there is no known threshold at which they may pose a health risk . This study investigated the potential exposure of young children to aflatoxin contamination in Kisumu County, Kenya. Kisumu County may have the potential for low to high levels of aflatoxin contamination due to prevailing weather conditions as well as reliance on maize, sorghum, cassava and rice as the main staple foods, groundnuts as snack and omena ( Rastrienobola argentea ) and milk as cheap source s of protein. These foods are also used as weaning foods in the County. Samples of omena , rice, groundnuts, cassava, maize, and sorghum were collected from Kibuye wholesale market , Kibuye open air market , Ahero market , Oile market and Mamboleo market in Kisumu County using a combination of cluster and systematic sampling. Processed cow’s milk samples were collected from supermarkets and raw cow’s milk samples from 3 market milk bazaars in the County . Analysis of solid foods was done using HELICA Total Aflatoxin Assay, intended for quantitative detection of aflatoxin B 1 , B 2 , G 1 and G 2 . Milk sampling was done using the European model outlined in the Codex Alimentarius. Aflatoxin M 1 levels in milk were analyzed using HELICA Aflatoxin M 1 Assay. Aflatoxin levels in the foods ranged from 0 to 34.5 ppb aflatoxin B 1 , 0.012 to 0.127 ppb aflatoxin M 1 in processed milk and 0.0002 to 0.013 ppb aflatoxin M 1 in raw milk . All the food products , except cassava, had samples with detectable aflatoxin levels. Daily aflatoxin consumption ranged from 35 ng (4.43/kgBw/day) to as high as 872 ng (110.4 ng/kgBW ). These findings indicate that weaning children in Kisumu County are potentially exposed to levels of aflatoxins above the permissible amounts , given that the food stuffs that were analyzed are the commonly used weaning food items. Its effects on their health should be assessed and efforts taken to reduce potential exposure both from the commonly suspected sources as well as from milk.

Implication of Aflatoxin Contamination in Agricultural Products

Aflatoxins are secondary fungal metabolites that contaminate agricultural commodities and can cause sickness or death in humans and animals. Risk of aflatoxin contamination of food and feed in Africa is increased due to environmental, agronomic and socio-economic factors. Temperature, food substrate, strain of the mould and other environmental factors are some parameters that effect mycotoxin production. Preventing mycotoxin production at farm level is the best way to control mycotoxin contamination. Advances in molecular techniques and other decontamination methods such as gamma-irradiation and microwave heating could help to deal with these issues. Mycotoxins could be used as an energy source for a group of aerobic microorganisms, which are suitable to mycotoxin biodegradation. Several protocols have been provided to biodegrade mycotoxins in food and feed using potential bacteria such as Lactobacillus and Bifidobacterium. However, there are varieties of responses between different microorganisms against mycotoxins. For example, Bacillus brevis were not affected by high concentrations of trichothecene. Application of microorganisms needs to be evaluated from a safety point of view. Application of microorganisms on mycotoxin degradation, food and feed materials also need to be investigated. Further studies need to be conducted to address the seasonal variation of aflatoxin contamination in food and feed. Understanding the seasonal variation could help demonstrate and develop more effective decontamination methods. For example, it is postulated that mycotoxin issues due to monsoons in Hungary could possibly be concluded to technical difficulties in pre- and post-harvest operations. Application of advanced methods such as DNA biosensors and infrared spectroscopy for rapid and accurate detection of mycotoxin and related fungi is increasing dramatically. Application of new and advanced detection techniques could enable the agricultural industry to deal more effectively with the occurrence of aflatoxin contamination.

Assessment of mycotoxin risk on corn in the Philippines under current and future climate change conditions.

This study attempts to assess the risk of mycotoxins (aflatoxins and fumonisins) contamination on corn in the Philippines under current and projected climate change conditions using fuzzy logic methodology based on the published range of temperature and rainfall conditions that favor mycotoxin development. Based on the analysis, projected climatic change will reduce the risk of aflatoxin contamination in the country due to increased rainfall. In the case of fumonisin contamination, most parts of the country are at a very high risk both under current conditions and the projected climate change conditions.

Assessing Purdue Improved Crop Storage (PICS) bags to mitigate fungal growth and aflatoxin contamination

Storing maize in regions of the world without sufficient drying and storage capacity is challenging due to the potential risk of aflatoxin contamination produced by Aspergillus flavus. This study sought to determine if storage of maize in Purdue Improved Crop Storage (PICS) bags prevents mold growth and aflatoxin accumulation. PICS bags are a three-layer, hermitic bag-system that forms a barrier against the influx of oxygen and the escape of carbon dioxide. Maize conditioned at 12, 15, 18, and 21% grain moisture was inoculated with 50 g of maize kernels infected with fluorescent-marked strain of A. flavus. The grain was stored in either PICS or woven bags at 26 °C, and percent oxygen/carbon dioxide levels, fungal growth, aflatoxin, moisture content, and kernel germination were assessed after 1 and 2 months incubation. Maize stored in woven bags was found to equilibrate with the ambient moisture environment over both storage periods, while PICS bags retained their original moisture levels. Aspergillus flavus growth and aflatoxin accumulation were not observed in maize stored in any PICS bags. No aflatoxin B1 was detected in woven bags containing low-moisture maize (12 and 15%), but detectable levels of aflatoxin were observed in high moisture maize (18 and 21%). The percentage of oxygen and carbon dioxide within PICS bags were dependent on initial grain moisture. Higher carbon dioxide levels were observed in the bags stored for 1 month than for 2 months. High initial moisture and carbon dioxide levels correlated with low kernel germination, with the 18 and 21% treatment groups having no seeds germinate. The results of the study demonstrate that storage of maize in PICS bags is a viable management tool for preventing aflatoxin accumulation in storage.

Potential for aflatoxin B1 and B2 production by Aspergillus flavus strains isolated from rice samples

In this study, we investigated the potential for aflatoxin B1 (AFB1) and B2 (AFB2) production in rice grain by 127 strains of Aspergillus flavus isolated from rice grains collected from China. These strains were inoculated onto rice grains and incubated at 28°C for 21days. AFB1 and AFB2 were extracted and quantified by high-performance liquid chromatography coupled with fluorescence detection. Among the tested strains, 37% produced AFB1 and AFB2 with levels ranging from 175 to 124101μgkg−1 for AFB1 and from not detected to 10329μgkg−1 for AFB2. The mean yields of these isolates were 5884μgkg−1 for AFB1 and 1968μgkg−1 for AFB2. Overall, most of the aflatoxigenic strains produced higher levels of AFB1 than AFB2 in rice. The obtained information is useful for assessing the risk of aflatoxin contamination in rice samples.

Aspergillus parasiticusCommunities Associated with Sugarcane in the Rio Grande Valley of Texas: Implications of Global Transport and Host Association WithinAspergillusSectionFlavi

In the Rio Grande Valley of Texas (RGV), values of maize and cottonseed crops are significantly reduced by aflatoxin contamination. Aflatoxin contamination of susceptible crops is the product of communities of aflatoxin producers and the average aflatoxin-producing potentials of these communities influence aflatoxin contamination risk. Cropping pattern influences community composition and, thereby, the epidemiology of aflatoxin contamination. In 2004, Aspergillus parasiticus was isolated from two fields previously cropped to sugarcane but not from 23 fields without recent history of sugarcane cultivation. In 2004 and 2005, A. parasiticus composed 18 to 36% of Aspergillus section Flavi resident in agricultural soils within sugarcane-producing counties. A. parasiticus was not detected in counties that do not produce sugarcane. Aspergillus section Flavi soil communities within sugarcane-producing counties differed significantly dependent on sugarcane cropping history. Fields cropped to sugarcane within the previous 5 years had greater quantities of A. parasiticus (mean = 16 CFU/g) than fields not cropped to sugarcane (mean = 0.1 CFU/g). The percentage of Aspergillus section Flavi composed of A. parasiticus increased to 65% under continuous sugarcane cultivation and remained high the first season of rotation out of sugarcane. Section Flavi communities in fields rotated to non-sugarcane crops for 3 to 5 years were composed of <5% A. parasiticus, and fields with no sugarcane history averaged only 0.2% A. parasiticus. The section Flavi community infecting RGV sugarcane stems ranged from 95% A. parasiticus in billets prepared for commercial planting to 52% A. parasiticus in hand-collected sugarcane stems. Vegetative compatibility assays and multilocus phylogenies verified that aflatoxin contamination of raw sugar was previously attributed to similar A. parasiticus in Japan. Association of closely related A. parasiticus genotypes with sugarcane produced in Japan and RGV, frequent infection of billets by these genotypes, and the ephemeral nature of A. parasiticus in RGV soils suggests global transport with sugarcane planting material.

Aflatoxin contamination in tahini

Sesame seeds can be contaminated with aflatoxins during growth or storage. Therefore, tahini, a sesame seed-based product, has potential risk of aflatoxin contamination. In this study, a total of 104 tahini samples collected from Central Anatolian region of Turkey were analysed for aflatoxin contamination. Analysis of samples was carried out by high-performance liquid chromatography with fluorescence detection after immunoaffinity column clean-up, with recoveries ranging from 70.3 to 82.4%. In terms of incidence and quantity, aflatoxin B1 was the predominant mycotoxin detected in 15 samples, with contamination levels ranging from 0.31 to 2.53 μg/kg. The mean level of total aflatoxins in contaminated samples was found to be 1.17±0.55 μg/kg. Our data revealed that aflatoxin B1 and total aflatoxins levels determined in tahini samples were within the Turkish Food Codex limits. The incidence of contaminated tahini samples indicated that a regular surveillance program should be established to monitor the occurrence of aflatoxins in tahini.

Fungal species isolated from peanuts in major Kenyan markets: Emphasis on Aspergillus section Flavi

A survey was conducted in Nairobi, Nyanza and Western provinces in Kenya between March and July 2009 with 1263 peanut products sampled out of which 705 samples underwent microbial analysis. The study aimed at determining the incidence of fungal species – emphasis on Aspergillus section Flavi – associated with peanut products. A 0.5 kg representative sample was obtained from each surveyed vendor and the colony forming units (CFU) of fungal species determined. The samples were also analyzed for total aflatoxin level while isolates of Aspergillus flavus and Aspergillus parasiticus were screened for production of aflatoxin B1, B2, G1 and G2. Eight fungal species were detected in the samples and were in decreasing order of CFU/g of sample: A. flavus S-strain (467), A. flavus L-strain (341), Penicillium spp. (326), Aspergillus niger (156), Aspergillus tamari (27), Aspergillus alliaceus (21), A. parasiticus (10), and Aspergillus caelatus (5). The overall incidence of A. flavus S-strain in samples from Nairobi was 92 and 1425% higher than samples from Nyanza and Western regions, respectively. The combined incidence of A. flavus and A. parasiticus was varied significantly (p ≤ 0.05) with peanut product: peanut flour (69%), shelled raw peanuts (53%), spoilt peanuts (49%), boiled podded peanuts (45%), podded peanuts (39%), peanut butter (31%), fried peanuts (22%) and roasted peanuts (20%). Seventy three percent of A. flavus and A. parasiticus isolates produced at least one of the aflatoxin types, with 66% producing aflatoxin B1. The total aflatoxin level among peanut products ranged from 0 to 1629 μg/g; and there was a positive correlation (r = 0.2711) between the incidence of A. flavus and A. parasiticus, and total aflatoxin level. The high incidence of aflatoxin producing fungi in peanuts traded in Kenyan markets implies a risk of aflatoxin contamination, highlighting the need for stakeholders to promote sound practices at all stages of the peanut value chain in order to minimize market access by non-complying products.

AFLA-maize, a mechanistic model for Aspergillus flavus infection and aflatoxin B1 contamination in maize

A mechanistic weather-driven model was developed based on the infection cycle of Aspergillus flavus on maize to predict the risk of aflatoxin contamination in field on a daily basis from silk emergence to harvest; hourly data of temperature, relative humidity and rain were used as model input. The work was done in four steps: (i) development of the model prototype; (ii) collection of Italian field data on aflatoxin contamination in maize with related crop and weather data; (iii) development of a probability index to exceed the legal limit of 5μg of aflatoxin B1 per kg of unprocessed maize by combining model predictions and field data in a logistic regression; and (iv) validation with Italian data of the probability index and release of the predictive model, named AFLA-maize. Predictions of maize contamination above the threshold of 5μg/kg in the data set used for parameterization of the regression equation were correct for 73% of field samples; 59% and 14%, respectively, were not contaminated and contaminated. In a second independent data set, 68% of samples were correctly predicted. The model AFLA-maize provides prediction of A. flavus infection and aflatoxin contamination along the growing season and at harvest. This information is useful to support decision-making for (i) crop management, (ii) harvest timing, (iii) maize lots cleaning and logistic, and (iv) maize sampling for aflatoxin analysis at consignment.

Economic Risks of Aflatoxin Contamination in Marketing of Peanut in Benin

Aflatoxin (AF) is a human health, nutrition, and financial risk to many people in the developing world. AF contamination in peanut is caused by the fungi:Aspergillus flavusandAspergillus parasiticus. AF is a potent carcinogenic toxin that also causes millions of dollars of financial losses to people in Africa. The fungus producing the AF can be reduced to an acceptable level by proper drying, sorting, storage, and cleaning of peanut. Government intervention and regulation can also encourage market participants to reduce AF contamination. In this paper, we examine the financial risk associated with sorting, and storing of peanut and peanut products along the marketing chain. Study results show that the prices paid for peanut, prices received, the costs of sorting and storage are dominant factors in reducing AF levels in peanut. Practices such as drying, sorting, and storing, however, pose financial risks to market traders of peanut. Unless government intervenes by requesting an AF-reduced peanut and provides assistance for market liberalization where market participants consider quality in trading decisions, suppliers of peanut will be reluctant to adopt AF-reducing techniques.

The Research of Impact Factor of Aflatoxins in Oil-Tea Camellia Seed and Oil-Tea Camellia Seed Cake

Through sampling from production enterprise, and testing methods design, the risk of aflatoxin contamination of Camellia oleifera seed was explored. It was proved that the chance of aflatoxin contamination is very small, for mainly processing happened in wintry and spring. After 7 days, 14 and 21 days artificial inoculation, the aflatoxin B1 in the cake was 1.7, 3.6 and 9.9 μg/kg, respectively, while the quality in camellia benevolence was 2.6, 1.8 μg/kg and below the detection limit 0.2 μg/kg. The results explained that Camellia oleifera seed can be untainted by aflatoxin in hot and humid climate conditions. The study answered the question whether the Camellia oleifera seed could be contaminated by aflatoxin, which wa an unresolved problem for a long-term. Also the conclusion was a warning for the safety of storage and production of Camellia oleifera seed in high temperature seasons.

Factors associated with the incidence of Aspergillus section Flavi and aflatoxin contamination of peanuts in the Busia and Homa bay districts of western Kenya

The aim of this study was to identify agronomic, ecological and sociocultural factors that could be modified to reduce the risk of aflatoxin contamination of peanuts from western Kenya. Presence of fungi within section Flavi of the genus Aspergillus and levels of total aflatoxin were determined for 436 peanut samples from the Busia and Homa bay districts. A total of 1458 cultures of Aspergillus flavus or A. parasiticus isolated from the samples were assayed for production of aflatoxin B1, B2, G1 and G2. Associations among the incidences of fungal species, incidences of samples with ≥10 μg kg−1 aflatoxin, production of specific aflatoxin types and various agronomic, ecological and sociocultural factors were modelled with chi‐squared and logistic regression methods. The predominant species were A. flavus L‐strain (78% incidence), A. flavus S‐strain (68%) and A. niger (65%). Occurrence of A. caelatus, A. alliaceus and A. tamarii in Kenya was also documented. Samples from the Busia district were three times (odds ratio = 3·01) as likely to contain ≥10 μg kg−1 of total aflatoxin as were samples from the Homa bay district, while samples containing A. flavus S‐strain were 96% more likely to exceed this threshold compared with samples from which this fungus was not isolated. Grading, planting improved cultivars and membership of a producer marketing group were negatively associated with the incidence of A. flavus, while crop rotation was negatively correlated with the incidence of B aflatoxins. These sociocultural factors can be modified to reduce the risk of peanut contamination with aflatoxin.

Modelling the effect of water activity and temperature on growth rate and aflatoxin production by two isolates of Aspergillus flavus on paddy

This study was conducted to characterize the growth of and aflatoxin production by Aspergillus flavus on paddy and to develop kinetic models describing the growth rate as a function of water activity (a(w)) and temperature. The growth of A. flavus on paddy and aflatoxin production were studied following a full factorial design with seven a(w) levels within the range of 0·82-0·99 and seven temperatures between 10 and 43°C. The growth of the fungi, expressed as colony diameter (mm), was measured daily, and the aflatoxins were analysed using HPLC with a fluorescence detector. The maximum colony growth rates of both isolates were estimated by fitting the primary model of Baranyi to growth data. Three potentially suitable secondary models, Rosso, polynomial and Davey, were assessed for their ability to describe the radial growth rate as a function of temperature and a(w). Both strains failed to grow at the marginal temperatures (10 and 43°C), regardless of the a(w) studied, and at the a(w) level of 0·82, regardless of temperature. Despite that the predictions of all studied models showed good agreement with the observed growth rates, Davey model proved to be the best predictor of the experimental data. The cardinal parameters as estimated by Rosso model were comparable to those reported in previous studies. Toxins were detected in the range of 0·86-0·99 a(w) with optimal a(w) of 0·98 and optimal temperature in the range of 25-30°C. The influences of a(w) and temperature on the growth of A. flavus and aflatoxin production were successfully characterized, and the models developed were found to be capable of providing good, related estimates of the growth rates. The results of this study could be effectively implemented in minimizing the risk of aflatoxin contamination of the paddy at postharvest.

Aflatoxin B1 degradation by Bacillus subtilis UTBSP1 isolated from pistachio nuts of Iran

Pistachio nuts are among the commodities with the highest risk of aflatoxin contamination in Iran. Aflatoxin B1 (AFB1) is one of the most hazardous mycotoxins for humans and livestock. In nature, there are microorganisms which are capable of reducing aflatoxins contamination in food and feed products. In this study, Bacillus subtilis strain UTBSP1 was isolated from pistachio nuts and studied for the degradation of AFB1. The AFB1 contents were determined by the use of HPTLC and HPLC as well as multiple reactions monitoring (MRM) method in LC–MS/MS. The results indicated B. subtilis UTBSP1 could considerably remediate AFB1 from nutrient broth culture and pistachio nut by 85.66% and 95%, respectively. Cell free supernatant fluid caused an apparent 78.39% decrease in AFB1 content. The optimal conditions for AFB1 degradation by cell free supernatant appeared at 35–40 °C, during 24 h. Furthermore, the results indicated that AFB1 degradation is enzymatic and responsible enzymes are extracellular and constitutively produced. The destructive AFB1 differed from standard AFB1 chemically, and lost a fluorescence property.

Susceptibility of steeped and heat dried cowpea flour to fungal growth and aflatoxins production

In vitro studies were carried out to determine the susceptibility of flours from steeped and heat dried cowpea to fungal growth and aflatoxins production. A 2 × 7 factorial experimental design with 2 levels of steeping time of cowpea grain in water (0 and 3 min steeping) and 7 levels of drying temperatures of the grains ranging from 35 to 120°C were used for flour production. Processed flours were used to prepare solid Cowpea Flours Agar media (CFA). Aflatoxigenic strain (Aspergillus flavus) was inoculated to these media and incubated at 30°C for 7 days. Yeast Extract Sucrose (YES) was used as control. Radial growth of colonies formed was measured and aflatoxins production was determined using High Performance Liquid Chromatography (HPLC). After incubation period, maximal growth of A. flavus colonies was observed in all CFA. The aflatoxin levels detected in CFA prepared with flour dried at 35 to 50°C ranged from 4.40 to 29.63 µg toxin /kg flour, while higher levels ranging from 27.45 to 75.00 µg toxin /kg flour were detected in CFA prepared with flours dried at 60 to120°C. The effect of steeping cowpea in water on aflatoxin production was dependent on drying temperatures. The average aflatoxin levels in CFA flours obtained from non steeped and steeped grains were 11.16 and 16.14 µg toxin /kg flour respectively and were statistically similar at P= 0.05 at 35 to 50°C drying temperatures. It was concluded that drying steeped or non steeped cowpea at temperatures less than 60oC exposes cowpea flour to minimal risk of aflatoxin contamination. Key words: Cowpeas flour, aflatoxins, drying temperature.

Aflatoxin control and prevention strategies in key crops of Sub-Saharan Africa

Aflatoxins are secondary fungal metabolites that contaminate agricultural commodities and can cause sickness or death in humans and animals. Risk of aflatoxin contamination of food and feed in Africa is increased due to environmental, agronomic and socio-economic factors. Environmental conditions especially high humidity and temperature favour fungal proliferation, but also drought conditions increase risk of aflatoxin contamination. Low-input farming practices compound fungal and aflatoxin contamination of crops. The socio-economic and food security status of the majority of inhabitants of sub-Saharan Africa leaves them few options for choosing low-risk and high quality products. Several technologies have been tested in Africa to reduce aflatoxin risk. Field management practices that increase yields can reduce the risk of aflatoxin development. They include use of resistant varieties, crop rotation, well-timed planting, weed control, pest control especially control of insect pests and avoiding drought and nutritional stress through fertilization and irrigation. Measures to stop the infection process by controlling the aflatoxin causing fungi in the field are achieved through use of pesticides and atoxigenic fungi to competitively displace toxigenic fungi, and timely harvest. Post-harvest interventions that reduce aflatoxin include rapid and proper drying, proper transportation and packaging, sorting, cleaning, drying, smoking, post harvest insect control, and the use of botanicals or synthetic pesticides as storage protectants. Another approach is to reduce the frequent consumption of ‘high risk’ foods (especially maize and groundnut) by consuming a more varied diet, and diversifying the diet into less risky staples like sorghum and millet. Chemo-preventive measures that can reduce aflatoxin effect include daily consumption of chlorophyllin or oltipraz and incorporating hydrated sodium calcium alumino-silicates into the diet. Reduction and detoxification of aflatoxin is often achieved physically (sorting, physical segregation, flotation etc.), chemically (e.g. calcium hydroxide, ammonia) and microbiologically by incorporating pro-biotics or lactic acid bacteria into the diet. Millers can use blending of less and more contaminated products to reduce the overall risk. There is need for efficient monitoring and surveillance with cost-effective sampling and analytical methods to reduce risk in Africa. Public education and awareness can sensitize the population on aflatoxin risk and its management. Key words: Aflatoxin, Sub-Saharan Africa, control measures.

Treatment of primary hepatocellular carcinoma

Primary hepatocellular cancer is the fifth most common solid tumor worldwide. Its incidence is the highest in the Third World, however, a risen incidence has been observed recently also in developed countries, due to increasing migration. In Asia and Africa the main etiological factor for HCC is chronic HBV infection, whereas in the Western world HCV etiology predominates. Additional increase in HCC incidence is expected as a consequence of climate change, since risk of aflatoxin contamination in agricultural products increases with hot and dry growing conditions. Aflatoxins are the most potent hepatocarcinogens in nature; therefore minimization of aflatoxin exposition will be a main task of food security in the future. The majority of HCC patients are diagnosed in advanced stages, and treatment possibilities are limited for this patient population. Follow-up of risk populations by means of tumor surveillance is therefore essential. Experience with systemic chemotherapy has been disappointing with low response rates and high toxicity. Recently, novel treatment options have emerged, including the use of specific targeted agents, blockers of signaling pathways involved in hepatocarcinogenesis. Sorafenib, an oral multikinase-inhibitor is the first systemic agent to demonstrate survival benefit in advanced hepatocellular cancer. Several new, promising therapeutic options are being tested in clinical trials.

Correlation Between Aflatoxin Contamination and Various USDA Grade Categories of Shelled Almonds

The California almond industry is interested in determining if there is a correlation between aflatoxin contamination and almonds classified into various U.S. Department of Agriculture (USDA) grades. A 12 000 g sample was taken from each of 50 lots of shelled almonds. The almonds in each sample were then partitioned into five USDA grades: high quality (HQ), insect damage (ID), mold damage (MOD), mechanical damage (MED), and other defects (OD). Across all 50 samples, kernels in the HQ grade accounted for 83.7% of the kernel mass and 3.2% of the aflatoxin mass. Conversely, kernels in the remaining four damage grades (ID, MOD, MED, and OD) accounted for 16.3% of the kernel mass and 96.8% of the aflatoxin mass. ID kernels had the highest risk for aflatoxin contamination. Almonds in the ID grade accounted for 76.3% of the total aflatoxin mass and 7.2% of the kernel mass. Regression equations were developed to predict the aflatoxin concentration in each 12 000 g sample by measuring the aflatoxin mass in one or more of the four damage grades. Regression equations demonstrated that aflatoxin mass only in the insect damaged kernels was also an effective way to predict the aflatoxin concentration in each 12 000 g sample.

Modelling climatic risks of aflatoxin contamination in maize

Aflatoxins are highly carcinogenic mycotoxins produced by two fungi, Aspergillus flavus and A. parasiticus, under specific moisture and temperature conditions before harvest and/or during storage of a wide range of crops including maize. Modelling of interactions between host plant and environment during the season can enable quantification of preharvest aflatoxin risk and its potential management. A model was developed to quantify climatic risks of aflatoxin contamination in maize using principles previously used for peanuts. The model outputs an aflatoxin risk index in response to seasonal temperature and soil moisture during the maize grain filling period using the APSIM’s maize module. The model performed well in simulating climatic risk of aflatoxin contamination in maize as indicated by a significant R2 (P ≤ 0.01) between aflatoxin risk index and the measured aflatoxin B1 in crop samples, which was 0.69 for a range of rainfed Australian locations and 0.62 when irrigated locations were also included in the analysis. The model was further applied to determine probabilities of exceeding a given aflatoxin risk in four non-irrigated maize growing locations of Queensland using 106 years of historical climatic data. Locations with both dry and hot climates had a much higher probability of higher aflatoxin risk compared with locations having either dry or hot conditions alone. Scenario analysis suggested that under non-irrigated conditions the risk of aflatoxin contamination could be minimised by adjusting sowing time or selecting an appropriate hybrid to better match the grain filling period to coincide with lower temperature and water stress conditions.