Growth

• Mold growth depends on four critical factors: spores, food, temperature and a considerable amount of moisture. If even one of these factors is not suitable, mold growth will be limited; however, mold spores are virtually everywhere and cannot possibly be eliminated from the environment. It is impossible to remove mold food because the oil in human skin left behind after touching any object provides food for spores. Mold grows at the same temperatures that people prefer, so temperature is not a means of controlling mold growth.
  
  

Moisture

• The only factor that can be used to control mold growth is moisture. Mold requires a considerable amount of moisture to grow. People can reasonable control the amount of mold and mildew growth in their homes by keeping moisture levels at a minimum. Humidity levels higher than 70 percent can cause mold growth. Large, health risk outbreaks of mold growth in buildings happens when porous materials remain in liquid water over a period of time.
  
  

Color

• Visible mold colonies found on objects in the home are typically white to greenish or black in color. These types of mold can often be controlled with dehumidification systems. Unseen mold colonies that can grow inside walls will eventually stain walls a yellowish or pinkish color. If you discover discoloration on walls, a professional should be called to determine the source of serious moisture accumulations within the drywall.
  
  

Species

• The most common species of mold and mildew found in home can have effects on humans that range from allergy symptoms to serious health problems. Alternaria is most often found in plant soil and around windows and can cause common allergy symptoms. Memnoniella is found on wood, paper and cotton and generally grown in conjunction with stachybotrys, which is considered to be a toxic black mold. Penicillium is very common in homes. It is found in soil, food and dust and can accumulate in the air. Penicillium is known to cause allergies, infections and other serious health problems.