Mold mites is a general term that refers to a variety of mites (e.g. members of the families Acaridae, Pyroglyphidae, Tarsonemidae) found in association with fungal growths such as mildew, moldy grain, and spoiled food. Many of these mites also are common in house dust.
Mold mites are very common but usually go unnoticed except when they become abundant. They can infest stored food and grain and cause tremendous losses although they are more commonly an annoyance and nuisance and not injurious. However, as with house dust mites, the exuviae and feces of dust mites may contribute to the development of atopic asthma, rhinitis, and other allergic reactions such as dermatitis in sensitive individuals. Mold mite populations develop to significant levels only where there are microclimates with sufficient humidity and a substrate that will support fungal growth, e.g. areas with leaky pipes and porous surfaces (e.g. wood, rugs, furniture), poorly sealed windows, attics with leaky roofs, hygroscopic foods, and containers of grains, flour, potatoes, etc. The longer you keep infested foods, the higher the mite populations.
Elimination of mold mites is an unrealistic goal: they are ubiquitous in human habitations and food stuffs and, even if they could be eliminated from a household, would soon reinfest. A more useful approach is to limit their population size by denying them the resources they need to develop: moldy organic matter and high local humidities. Mold mites are very small (typically a half millimeter or less in length) and the surface area to volume ratio applies to them: they find it difficult to retain body moisture. Anything that removes moisture (e.g. cleaning up spills, disposing of moldy food, fixing leaky pipes, increasing ventilation with fans, using air conditioning or central heating) from a home will reduce mold mite populations (as well as dust mites and molds - both of which are important sources of antigens).