Poisonous substances produced by molds or fungi on agricultural products like corn and peanuts as well as on animal feeds pose great health hazards to humans and livestock. These poisonous substances are generally called mycotoxins.

In ancient times, people attributed the ravages of fungi to the anger of the gods. Thus, the Romans even designated a deity, Robigus, as the god of the rust. To appease his wrath, they organized festival in his honor, which they called Robigalia.

The story also goes that a strange and horrible disease broke out in 1951 in the small village of Pont-St. Esprit in France. The villagers panicked and thought that some evil spirits attacked them. Some of them died, as physicians did not know what caused the disease.

Later, someone recognized the mysterious disease as ergotism or "St. Anthony's fire," which was prevalent in the Middle Ages in northern Europe, particularly in regions where the consumption of bread made of rye was high. In the case of French village, it was found out that the disease resulted from eating bread made of contaminated flour.

The cause of the disease, according to the Encyclopedia Britannica, was ergot or a fungus. Technically called sclerotium, an ergot is a special part of a fungus that develops on plants.

Thus, chances are great that your corn grains or peanuts are infected by mycotoxin if these have black powdery filaments attached to them. Aflatoxin is one of the mycotoxins or poisonous substances produced by molds on foods and feeds that pose economic and health hazards.

According to Dr. Ricardo L. Cachuela, executive director of the Bureau of Postharvest Research and Extension in the Science City of Muñoz, Nueva Ecija, aflatoxin is poisonous substance produced by molds or fungi on agricultural products. He said this substance has put the agriculture industry at risk due to its severe impact on humans and livestocks.

To avoid the ill effects of aflatoxin, it would do well for everybody to be familiar with what this poisonous substance is all about.

FUNGI AND MYCOTOXINS

The words fungi and mycotoxins are interrelated with each other. However, not all fungi are poisonous, as the edible mushroom is also a fungus.

Fungi constitute a group of living organisms without chlorophyll and, hence, depend on other organic matter for their nutrition. A fungus consists of a mass of branched, tubular or thread-like filaments, which are called hyphae or mycelium. It reproduces by means of spores, either sexually or asexually.

According to a BPRE primer, while a number of fungi are useful, some are also poisonous. For instance, yeasts and mycelial fungi are important in the fermentation of industrial products like bread, wines and beer, as well as in bioremediation such as the breakdown of tannins in tannery effluents. Fungi are also used in the commercial production of antibiotics, vitamins, enzymes, and organic acids.

On the other hand, some entomogenous fungi can be used for biological control, while others are important in biodegration and biodeterioration as well as the deterioration of plant debris.

Some fungi cause infection or allergic responses in animals like ringworm, plant diseases like late blight of potatoes, and contamination of consumer goods by mycotoxins. In foods like corn and peanuts, field fungi may invade before harvest and storage fungi occur after harvest.

Experts say that the prevailing high temperature and relative humidity in the Philippines are very conducive for mycotoxins production, most especially by aflatoxin-producing molds. Agricultural products with molds have very poor marketability or may not even be bought by consumers. Such products would surely fail to pass strict quality standards imposed by the local and global markets as well as by selective consumers.

AFLATOXIN

BPRE experts stress that aflatoxin is a potent cancer-causing substance or carcinogen formed by the fungi Aspergillus flavus and Aspergillus parasiticus. The mold grows when farm crops are exposed to prolonged hot weather, drought, insect damage, and high moisture content.

Corn, peanut, copra and cassava are usually contaminated by aflatoxin.

Among animals, mycotoxins ingestion could weaken their immune system, resulting in decreased productivity, reproductive dysfunctions, and even death. It can also cause sickness or even death among humans.

Aflatoxin infection in poultry animals is manifested by: reduced weight gain and feed conversion; refusal to consume the feeds and reduced feed intake; immunological disorders; lower egg production and size; lower hatchability and increased egg breakage; and liver and kidney damage.

In large ruminants like cattle and carabaos, the animals suffer from weight loss, poor feed conversion, reduced milk production and butterfat content, reduced feed intake, feed refusal, liver damage, and presence of aflatoxin M1 in the milk.

Pigs also suffer from weight loss, poor feed conversion, feed refusal, reduced feed intake, vomiting, skin necrosis, bleeding, as well as liver and kidney damage.

As a result, livestock raisers would suffer from financial losses resulting from low productivity and high mortality of their animals.

Among humans, intake of aflatoxin-contaminated foods results in serious illnesses like liver cancer and kidney failure. Inhalation of and direct contact with aflatoxin spores lead to skin itchiness, respiratory disorder, eye irritations, allergies, and poisoning.

Aflatoxins have also been linked with the occurrence of various chronic diseases like Indian childhood cirrhosis, chronic gastritis, kwashiorkor, and Reyes' syndrome. The latter has been reported in Thailand, Malaysia, New Zealand, Czechoslovakia, United States, Valenzuela, and Europe. It is characterized by fever, convulsions, vomiting, altered reflexes, as well as enlarged yellow liver and kidneys.

Consequently, impaired health would lead to diminished work efficiency and increased expenses related to the treatment of the disease or death of the afflicted individual.

In like manner, farmers, traders and millers also suffer severe losses from aflatoxin-contaminated products as a result of low returns, increased production cost, and fluctuating market conditions.

PREVENTION

As mentioned earlier, aflatoxin contamination can occur both in the field and in storage.

Under field condition, crops exposed to stress conditions and insect infestation are susceptible to aflatoxin contamination.

Farmers can prevent aflatoxin infection on their crops by adopting the following management practices: use fungus-resistant crop varieties, if any; practice crop rotation; adopt proper irrigation and fertilizer application techniques; and adopt integrated pest management practices.

Among corn farmers, mechanized planting promotes systematic, fast and efficient harvesting. Farmers can use the BPRE-developed 3-in-1 machine, which can be used as a planter, fertilizer applicator and cultivator, to increase their efficiency and productivity.

Farmers must take note also that harvested products are likewise prone to aflatoxin infection. Grains like corn deteriorate and spoil rapidly when recommended postharvest are not followed.

Thus, farmers would do well to observe the following: timely harvesting; immediate drying of grains to 14 percent moisture content; injury-free shelling; store the grains at 14 percent moisture content; keep the grains free from impurities; and apply integrated pest management practices.

It is also advisable to manually remove the moldy and discolored grains from the marketable grains. Another option is the water floatation method.

To prevent possible aflatoxin contamination, achieve better shelling recovery and minimize mechanical injury, shell the corn ears after these have been pre-dried to moisture content of 18 to 22 percent.

For faster and less expensive shelling, use the BPRE Improved Corn sheller. It can also cut down losses caused by manual shelling, as it is suitable to any size of corn ears. It can shell 2 tons of corn an hour with a shelling efficiency of 99.86 percent. Take note, damage on the kernel becomes an entry point of storage fungi.

Dry the shelled corn grains within 48 hours after shelling. During storage, the grains should be well aerated to prevent the accumulation of heat and water, which are the products of respiration, as the grains are still respiring.

Avoid the following as these favors the production of aflatoxin:

1. Storage of wet ears in plastic sacks for more than 10 days.

2. Shelling corn ears with moisture content of 26 percent or more.

3. Storage of shelled corn with 18 percent or more moisture content in plastic sack or spreading on floor with shed for more than 3 days.

4. Storage of unevenly dried corn grains.