Researchers have introduced a promising new sterilization technique that leverages X-ray irradiation to effectively decrease the viability of Aspergillus flavus in corn that is contaminated. This approach allows for sterilization while leaving the dangerous aflatoxin B1 (AFB1), produced by the fungus, intact.
Corn is a vital food source for billions of people and animals globally, but it is often tainted by aflatoxin B1, a potent carcinogen generated by the Aspergillus flavus fungus.
Consuming aflatoxin can lead to severe health problems for both humans and animals, along with economic setbacks for agricultural sectors. However, due to the fungus’s high infectivity and the risks posed by its toxin, conducting research and developing control methods in laboratories can prove challenging.
A recent study featured in the journal Toxins by researchers from Arizona State University and their global collaborators has revealed a promising sterilization method employing X-ray irradiation to limit the viability of Aspergillus flavus in contaminated corn. This technique ensures sterilization without damaging the hazardous aflatoxin B1 (AFB1) that the fungus generates.
By rendering Aspergillus flavus inactive, this method prevents the fungus from spreading spores and generating further aflatoxins. This is crucial for enabling more laboratories to participate in addressing the issue of fungal toxins. Stabilizing the levels of toxins allows researchers to devise and assess additional remediation methods aimed at aflatoxin degradation without the complications of ongoing fungal proliferation. Results indicated that a low radiation dose effectively halted the growth of Aspergillus flavus.
This research is part of a broader initiative involving Arizona State University researchers and international partners, backed by the National Institutes of Health, to explore affordable strategies to reduce aflatoxin transmission and exposure in underserved communities.
“We have recognized the issue of aflatoxin since the 1960s, yet it continues to be a widespread problem,” states Hannah Glesener, the study’s lead author. “X-ray irradiation of naturally contaminated corn is an exciting advancement in our research team’s efforts to develop solutions to aflatoxin-related challenges, such as chronic malnutrition.”
Glesener is a graduate research assistant at the Biodesign Center for Health Through Microbiomes and a PhD student in biological design at ASU’s School for Engineering of Matter, Transport, and Energy.
The research team is now assessing home cooking techniques for controlling this fungal toxin and examining the potential role of the human gut microbiome in detoxifying foods before they enter the bloodstream.
The Global Challenge of Mycotoxin Contamination
Aflatoxins are a variant of mycotoxins, which are harmful substances produced by molds or fungi that can infest various crops. Mycotoxins, such as aflatoxins, possess strong cancer-causing properties.
These toxins are created by Aspergillus species and are commonly found in crops like corn, cottonseed, and nuts, particularly in warm, humid climates that encourage mold growth. Fungi that produce aflatoxins can contaminate crops at multiple points including in the field, during harvesting, and while in storage.
Aflatoxin contamination is a significant concern worldwide, especially in humid tropical and subtropical regions. It’s most prevalent in Africa, Asia, and parts of South America, where warm conditions promote the growth of Aspergillus species.
According to the Food and Agriculture Organization of the United Nations, about 25% of the world’s food supplies are affected by mycotoxins, including aflatoxins. Countries like Nigeria, Kenya, India, and China are significantly impacted due to their climates and agricultural methods.
The Danger of Aflatoxin Contamination
Acute aflatoxin poisoning, known as aflatoxicosis, can occur following the ingestion of large amounts of contaminated food. Symptoms may include liver damage, nausea, vomiting, abdominal pain, and in severe cases, death.
Aflatoxins are particularly linked to a higher risk of liver cancer. The International Agency for Research on Cancer categorizes aflatoxins as Group 1 carcinogens, meaning they are scientifically confirmed to cause cancer in humans. Long-term exposure can also result in stunted growth in children and weakened immune systems, increasing vulnerability to infections.
The World Health Organization estimates that aflatoxins are responsible for 5% to 28% of global liver cancer cases, with the highest incidence in sub-Saharan Africa, Southeast Asia, and China. Each year, aflatoxin exposure is believed to lead to between 25,000 and 155,000 liver cancer fatalities worldwide. Moreover, even minimal exposure to aflatoxins can have severe impacts on animals.
Climate change is thought to worsen the aflatoxin threat by extending the geographical range of toxin-producing fungi, potentially raising contamination risks in new areas. Furthermore, the economic impact of aflatoxin contamination is substantial, especially in developing nations.
Study Overview
The main goal of the study, led by corresponding author and Assistant Research Professor Lee Voth-Gaeddert, was to establish the ideal irradiation dose needed to eliminate fungal viability while maintaining the concentration of aflatoxin B1 for later detoxification research.
These findings pave the way for the safe handling and study of contaminated food products without compromising the necessary structural and chemical properties for scientific investigation. It is hoped that these approaches will lead to scalable and efficient solutions to the issue of mycotoxin contamination across various regions, particularly in developing countries where food safety measures may be inadequate.
