Mycotoxin and Its Impact on Human Health

Introduction

Contamination of food items and feedstuffs by mycotoxins is a global phenomenon that results in various adverse health effects and complications. Fungi and mold produce toxic secondary metabolites known as mycotoxins. More than hundreds of mycotoxins have been identified, such as ochratoxins, aflatoxins, zearalenone, trichothecenes, patulin, and fumonisins. These mycotoxins are considered natural contaminants of agricultural products and food items worldwide. Several factors are responsible for the presence of mycotoxins in food items and crops, such as pest infection, climatic conditions, poor harvest, and improper storage practices. Exposure to mycotoxins mainly occurs due to ingestion and results in various diseases, such as mycoses and mycotoxicoses. These diseases cause adverse health effects in the body and eventually lead to death if untreated.

What Are Mycotoxins?

Mycotoxins are natural, toxic compounds produced by certain types of fungi (mold). Fungi that produce mycotoxins can grow on foodstuffs like nuts, cereals, dried fruits, and spices. Mold growth in these foodstuffs may occur before or after harvesting and storage under damp, warm, and humid conditions. Fungi consume organic matter under humid and favorable temperature conditions, proliferate into colonies, and produce high levels of mycotoxins. These mycotoxins help the fungi to grow in host cells by weakening the host's immune response.

Therefore, the production of mycotoxins and their toxic effects on the host tissues depends on the infected organism, immune response, metabolism, and susceptibility of the host tissues. The most commonly observed mycotoxins associated with adverse health effects in humans and livestock are patulin, aflatoxin, ochratoxin A, nivalenol, fumonisins, and zearalenone. Exposure to these mycotoxins can happen when a person eats the infected food or indirectly from animals that eat these contaminated feeds, primarily from milk and meat.

What Are the Different Types of Mycotoxins Found in Food?

According to reports from the Food and Agriculture Organization (FAO), in the United States, around 25 percent of the agricultural products in the world are contaminated with mycotoxins.

The most common types of mycotoxin, naturally occurring in foodstuffs, are the following.

• Aflatoxins.

• Zearalenone.

• Trichothecenes.

• Ochratoxins.

• Patulin.

• Fumonisins.

• Citrinin.

What Are the Health Effects Associated with Mycotoxins?

The effects of different mycotoxins on human health depend on various factors like age, weight, sex, exposure to other infectious agents, diet patterns, presence of other mycotoxins, amount of toxins exposed, and presence of pharmacologically active substances in the body. However, the severity of the toxic effects of mycotoxins may be aggravated by factors such as alcohol abuse, vitamin deficiency, infectious diseases, and low-calorie intake.

Mycotoxicosis is a disease condition that occurs due to poisoning with mycotoxins. These mycotoxins can induce acute and chronic health effects in humans through skin contact, ingestion, and inhalation. Through these sources, they enter the body and reach the lymphatic system and bloodstream. After reaching the body cells, they inhibit the synthesis of proteins, increase sensitivity to bacterial endotoxins, damage macrophages, and disrupt lung functions.

The health effects associated with common mycotoxins are the following.

• Aflatoxins - They cause hepatotoxicity (liver damage) and suppression of immune responses.

• Fumonisins - Induce nephrotoxicity (kidney damage), carcinogenicity (increased risk for cancer), hepatotoxicity, and immunosuppressive effects.

• Ochratoxin A - They are responsible for upper urinary tract diseases, nephrotoxicity, genotoxicity (chromosomal and DNA damage), carcinogenicity, and reduced body immune response.

• Trichothecenes - Toxic effects associated with trichothecenes cause genotoxicity, hepatotoxicity, and increased chance of infections.

• Deoxynivalenol - They cause diarrhea, nausea, reproductive defects, vomiting, and toxic health effects.

• Patulin - These mycotoxins may cause gastrointestinal irritation, stomach pain, gastritis, and neurological damage.

• Zearalenone - Ingestion of these mycotoxins causes hormonal imbalances, reproductive defects, and an increased cancer incidence.

What Are the Methods To Prevent Mycotoxins?

Mycotoxins can be prevented through physical, mechanical, chemical, and biological control methods.

• Mechanical Control - It aims to prevent fungus and mold growth in foodstuffs and crops. Continuous surveillance of mycotoxin in general products and agricultural crops is done in mechanical control. It can be achieved through agricultural practice techniques involving crop rotation techniques, reducing plant stress, and practicing proper cultivation and harvesting techniques. Mechanical sorting of clean products and infected products can also be done to prevent mycotoxins in foodstuffs.

• Physical Control - This technique involves thorough cleaning to remove generalized dirt. It can be done by proper washing using water or sodium carbonate.

• Chemical Control - Many chemicals, such as acids, bases, oxidizing agents, salts, chlorinating agents, and formaldehyde, effectively eliminate mycotoxins. Ammoniation can be done for contaminated feeds to detoxify ochratoxin and aflatoxin. In addition, chemicals such as ozone, sodium bisulfite, and ammonia can be used in stored grains to prevent fungal growth.

• Microbiological Methods - In this method, microbes and their enzymes can be used for mycotoxin detoxification. For example, lactic acid and propionic acid bacteria can inhibit the growth of fungi and, thus, mycotoxins.

How To Minimize the Risk From Mycotoxins?

Fungi that produce mycotoxins can grow on different types of crops and foodstuffs. This is because they can penetrate deep into the food rather than just expanding on the surface.

Certain preventive measures can be taken to minimize the exposure to mycotoxins as given below:

• Buy fresh nuts and grains as much as possible.

• Inspects foodstuffs like whole grains, dried fruits, and nuts for evidence of mold contamination before eating.

• Store grains and foodstuffs properly inside pest and insect-free dry containers or packets.

• Practice proper cultivating and harvesting procedures to avoid contamination.

• Try to avoid keeping foods for an extended period without using them.

Conclusion

Mycotoxins are toxic metabolites produced by fungi. Through ingestion of contaminated crops and foodstuffs, inhalation, or dermal contact, mycotoxins reach humans and cause mycotoxicoses. Mycotoxins cause several human health effects, such as cancer, liver damage, reproductive defects, neurological defects, and genetic mutations. Therefore, adequate measures must be taken to prevent and control these toxic substances in agricultural products during the cultivation, harvesting, and storage phases.