Mold and Yeast

Introduction

Mold and yeast are also known as fungi. Molds produce microscopic spores that are released into the air. Spores are always present in indoor and outdoor air. When mold spores land on a damp surface indoors they germinate and produce filamentous colonies that produce more spores. Unlike plants, molds do not have chlorophyll and do not need sunlight to reproduce. Molds obtain their nutrients from a variety of sources such a wood, decaying plant material, cardboard, paper, carpets, and food. Mold is common in the humid Northwest and growth is especially prevalent during warm, rainy periods in spring and early fall.

Moisture and Indoor Mold Growth

Mold growth indoors is always associated with excessive moisture. This may be due to roof or gutter leaks, leaking plumbing, or flooding. Sometimes the leak is not apparent and mold growth occurs in spaces between walls or under flooring. In cases where moisture is obvious the area should be completely dried, within 24 to 48 hours, if possible. Otherwise the mold will continue to spread. After surfaces are dry they should be washed with hot water and detergent. Water damaged absorbent materials such as sheet rock, ceiling tiles, and carpets may have to be replaced. The leak or other source of moisture should be eliminated. Providing proper ventilation will help to prevent return of the problem.

Health Concerns

A small amount of indoor mold is insignificant. Often the first sign of more extensive mold contamination is a musty, moldy odor. Not all molds are pathogenic. However, extensive mold growth indoors is always undesirable. Inhalation of mold spores over time has been linked to allergic reactions, asthma and other respiratory problems.

Pathogenic Molds

Some molds may cause human infections, others release toxins, and some are associated with allergies and respiratory conditions. Small amounts of mold are always present indoors. In general, it is not necessary to test for specific molds unless their growth in a residence or building is excessive and noticeable.

Stachybotrys - Black Mold

Stachybotrys chartarum or "black mold" is a greenish black mold with a sooty appearance. It grows on material with a high carbohydrate content and is associated with humid conditions indoors. It grows quickly following flooding. This mold is often found in the space between walls, growing on the paper surface of sheetrock. It also flourishes on water damaged wood, cardboard, and fiberboard. Stachybotrys does not infect humans or animals. However some, but not all, strains produce potent toxins. These toxins have been shown to suppress and damage the immune system. Chronic exposure to toxins may cause flu-like symptoms, muscle pain and headaches, fatigue, dermatitis, memory loss and even cancer. Stachybotrys is common in the northwest and has caused the closure of several schools and other buildings.

Collection and Analysis

Mold samples are obtained in a few different ways. Airborne mold samples are collected using a Petri dish with broad spectrum nutrient mold agar. Mold growing on a surface may be sampled using either a simple Biotape slide test kit, or by cutting out a small section of the surface up to 4 x 4 inches. For more information on sample collection and sample analysis Pyxis Laboratories has knowledgeable and qualified staff to answer your questions and to perform the analysis. Contact customerservice@pyxislab.com or call (503) 254-1794.