Mycotoxins are toxic and carcinogenic metabolites produced by fungi that colonize food crops. The most agriculturally important mycotoxins known today are aflatoxins, which cause liver cancer and have also been implicated in child growth impairment and acute toxicoses; fumonisins, which have been associated with esophageal cancer (EC) and neural tube defects (NTDs); deoxynivalenol (DON) and other trichothecenes, which are immunotoxic and cause gastroenteritis; and ochratoxin A (OTA), which has been associated with renal diseases. This review describes the adverse human health impacts associated with these major groups of mycotoxins. First, we provide background on the fungi that produce these different mycotoxins and on the food crops commonly infected. Then, we describe each group of mycotoxins in greater detail, as well as the adverse effects associated with each mycotoxin and the populations worldwide at risk. We conclude with a brief discussion on estimations of global burden of disease caused by dietary mycotoxin exposure.

Mycotoxins, toxins produced by fungi that colonise food crops, can pose a heavy economic burden to the US corn industry. In terms of economic burden, aflatoxins are the most problematic mycotoxins in US agriculture. Estimates of their market impacts are important in determining the benefits of implementing mitigation strategies within the US corn industry, and the value of strategies to mitigate mycotoxin problems. Additionally, climate change may cause increases in aflatoxin contamination in corn, greatly affecting the economy of the US Midwest and all sectors in the United States and worldwide that rely upon its corn production. We propose two separate models for estimating the potential market loss to the corn industry from aflatoxin contamination, in the case of potential near-future climate scenarios (based on aflatoxin levels in Midwest corn in warm summers in the last decade). One model uses the probability of acceptance based on operating characteristic (OC) curves for aflatoxin sampling and testing, while the other employs partial equilibrium economic analysis, assuming no Type 1 or Type 2 errors, to estimate losses due to proportions of lots above the US Food and Drug Administration (USFDA) aflatoxin action levels. We estimate that aflatoxin contamination could cause losses to the corn industry ranging from US$52.1 million to US$1.68 billion annually in the United States, if climate change causes more regular aflatoxin contamination in the Corn Belt as was experienced in years such as 2012. The wide range represents the natural variability in aflatoxin contamination from year to year in US corn, with higher losses representative of warmer years.

Growth impairment is a major public health issue for children in Tanzania. The question remains as to whether dietary mycotoxins play a role in compromising children's growth. We examined children's exposures to dietary aflatoxin and fumonisin and potential impacts on growth in 114 children under 36 months of age in Haydom, Tanzania. Plasma samples collected from the children at 24 months of age (N = 60) were analyzed for aflatoxin B1-lysine (AFB1-lys) adducts, and urine samples collected between 24 and 36 months of age (N = 94) were analyzed for urinary fumonisin B1 (UFB1). Anthropometric, socioeconomic, and nutritional parameters were measured and growth parameter z-scores were calculated for each child. Seventy-two percent of the children had detectable levels of AFB1-lys, with a mean level of 5.1 (95% CI: 3.5, 6.6) pg/mg albumin; and 80% had detectable levels of UFB1, with a mean of 1.3 (95% CI: 0.8, 1.8) ng/ml. This cohort had a 75% stunting rate [height-for-age z-scores (HAZ) < -2] for children at 36 months. No associations were found between aflatoxin exposures and growth impairment as measured by stunting, underweight [weight-for-age z-scores (WAZ) < -2], or wasting [weight-for-height z-scores (WHZ) < -2]. However, fumonisin exposure was negatively associated with underweight (with non-detectable samples included, p = 0.0285; non-detectable samples excluded, p = 0.005) in this cohort of children. Relatively low aflatoxin exposure at 24 months was not linked with growth impairment, while fumonisin exposure at 24-36 months based on the UFB1 biomarkers may contribute to the high growth impairment rate among children of Haydom, Tanzania; which may be associated with their breast feeding and weaning practices.

The endogenous cannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA) play vital roles during nervous system development. The degradation of 2-AG and AEA is mediated by monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), respectively. These enzymes are inhibited following developmental chlorpyrifos (CPF) exposure. To investigate whether this inhibition is persistent or whether accumulation of endocannabinoids in the brain occurs, 10-day-old rat pups were orally exposed daily for 7 days to either corn oil or increasing dosages of CPF (1, 2.5, or 5mg/kg), and forebrains were collected at 4, 12, 24, and 48h following the last administration. All dosages inhibited cholinesterase (ChE), FAAH, and MAGL, and elevated AEA and 2-AG levels with the greatest effect occurring at 12h with ChE, FAAH, AEA, and 2-AG and at 4h with MAGL. With the high dosage, return to control levels occurred with 2-AG (48h) only. With the medium dosage, return to control levels occurred with MAGL, 2-AG, and AEA (48h) but not with ChE or FAAH. With the low dosage, return to control levels occurred with MAGL (12h), ChE and 2-AG (24h), and AEA (48h) but not with FAAH. With the lowest dosage, peak inhibition of FAAH (52%) is greater than that of ChE (24%) and that level of FAAH inhibition is sufficient to induce a persistent pattern of elevated AEA. It is possible that this pattern of elevation could alter the appropriate development of neuronal brain circuits.

In this study, we developed a social network model of the global trade of maize: one of the most important food, feed, and industrial crops worldwide, and critical to food security. We used this model to analyze patterns of maize trade among nations, and to determine where vulnerabilities in food security might arise if maize availability was decreased due to factors such as diversion to nonfood uses, climatic factors, or plant diseases. Using data on imports and exports from the U.N. Commodity Trade Statistics Database for each year from 2000 to 2009 inclusive, we summarized statistics on volumes of maize trade between pairs of nations for 217 nations. There is evidence of market segregation among clusters of nations; with three prominent clusters representing Europe, Brazil and Argentina, and the United States. The United States is by far the largest exporter of maize worldwide, whereas Japan and the Republic of Korea are the largest maize importers. In particular, the star‐shaped cluster of the network that represents U.S. maize trade to other nations indicates the potential for food security risks because of the lack of trade these other nations conduct with other maize exporters. If a scenario arose in which U.S. maize could not be exported in as large quantities, maize supplies in many nations could be jeopardized. We discuss this in the context of recent maize ethanol production and its attendant impacts on food prices elsewhere worldwide.