Contamination
Contamination is an infection. Actually everything which is unwanted can be considered as contamination. During the germination of the spores and the growing of the mycelium it's very important to keep an ideal growing environment.
In general infections are caused by bacteria, moulds, viruses and/or insects. The most common contaminations are caused by bacteria. Sterilized rye and rice cakes are especially vulnerable to bacteria.
In general contaminations can be divided in 2 groups. The first group includes infections which grow inside the substrate and compete with the mycelium for the available nutrient media. These are called 'competitors'. The second group includes the pathogens. These attack the mushrooms itself. In general competitors are more common.
Contaminations appear in all colors. The most common colors of infection are yellow, green, orange and black. Therefore if your mushroom culture is infected it's not difficult to recognize it. Thanks to the white color of the mycelium you can quickly spot most contaminations. In some cases, though, it can be difficult to determine whether or not an infection is taking place. The color blue can mean a contusion in the substrate (or an indication of psilocybin) and the color yellow sometimes can indicate the ageing of the substrate. Therefore both these colors aren't always a sign of contamination. To be sure you need an experienced eye.
It's better to immediately place away from the growing environment any pots with substrate or agar cultures which are contaminated. If they are infected they will most surely infect the other pots or cultures. Some infections are really resistant and tough to get rid off.
So work always with sterilized material and check everything regularly for infection.
