What do Labels Tell Us?
Some sanitizers and disinfectants are labeled only for use on hard, nonporous surfaces; this does not include, for example, any wood surface. Reading a label is the one way to obtain information on how to use a given product. However, directions for use on labels can be somewhat misleading. Even if a label for a non-FCS chemical, such as a phenol, suggests that it can be used on inside walls, floors of a mushroom house, breezeways and track alleys before spawning or on spawning and casing equipment and then also tells us to apply only to surfaces that do not come in contact with compost, casing or crop —the grower has to use common sense and apply these non-FCS disinfectants carefully and MUST thoroughly rinse all surfaces with potable water prior to contact with any crop, compost or casing. Is it realistic to assume that one can spray disinfectants inside a mushroom house and not have some splash onto a porous surface or compost before spawning? Although labels are a good source of direction on how to use a chemical, the warning and limits on a label supercede any suggested application. With any application it is important to remember that unintentional but secondary contact is not tolerable.
Growers should read the disinfectants and sanitizer labels to know the percent active ingredient. Different brands of the same generic compound may have various percent active ingredients. Often, the percent active ingredient or ppm for final, terminal sanitation is much lower for FCS compared to that for general sanitation of walls, floors and equipment. The higher acceptable ppm is with non-FCS disinfectants.