Microorganisms can be divided into five major categories based on particle size and characteristics: filterable viruses, bacteria, actinomycetes, fungi, and algae. According to existing literature, there are as many as 60,000 to 80,000 known species of fungi. Fungi play a purifying role in the Earth’s ecological environment and serve specific functions in the production of pharmaceuticals and fermented foods; they are not entirely without benefit to the human body. However, the damage caused by fungi to food, homes, and buildings not only affects aesthetics but also poses hygiene risks; furthermore, they may lead to human illness or trigger allergies.

Microbial growth requires three essential conditions: a source of nutrients, warmth, and moisture. Microorganisms thrive in temperatures ranging from 15 to 20 degrees Celsius and in humid environments. Their spores float in the air and can attach to various surfaces at any time; when conditions are favorable, hyphae emerge from the spores to facilitate reproduction.

Effects on the Human Body: Damp environments are most prone to causing mold growth on food and other items. People living in such conditions may inhale microbial toxins, which can affect the respiratory system and lead to allergies or other chronic diseases. The health issues caused by microorganisms can be divided into three categories: infection, poisoning, and allergies. These conditions develop when airborne microorganisms, spores, or microbial metabolites enter the body through the mouth, food, or direct contact and accumulate over time. In severe cases, they can damage internal organs and nervous system function, and even lead to cancer.

By Michael Chiu, MWS, CI
Previously published in Ming Pao Daily News