Mold belongs to the microorganism, although it's one of the lowest living things, it's like any other living things, in the process of life activities, there is a close relationship with the surrounding environment. Mold growth mainly depends on nutrients, oxygen, water, temperature four living conditions.

　　1)Nutrients

　　Mould has the law of life activity that general organisms has, need to absorb nutrient material from outside environment constantly and make use of them, get from it the energy that carries on life activity to need, synthesize new cell material. Molds, like other living things, are made of carbon, hydrogen, oxygen, nitrogen and other chemical and mineral elements, in the process of its growth and reproduction, it is necessary to continuously absorb the necessary nutrients from the external environment, such as carbon, nitrogen, inorganic salt, auxin and so on.

　　2)Oxygen

　　There are mainly two kinds of aerobic mold and facultative aerobic bacteria, among which aerobic mold must be in the aerobic environment to grow and reproduce. Some foods are often placed in the "Oxygen Absorber" to make the food packaging environment is anaerobic state, destroy the necessary condition of mould growth and reproduction thereby, in order to achieve the purpose of extending food shelf life.

　　3)Water

　　Water is the most basic nutrient element for molds, Mold cells contain a lot of water, water content is about 85%~90%. The propagation of microorganisms such as molds is closely related to water, when AW(Water Activity)< 0.64, no mold can grow. The dry environment is not good for the growth and reproduction of microorganisms, drying can cause the cells to lose water, increase intracellular salt concentration or denaturate proteins, microorganisms will die gradually in dry conditions. Therefore, some dry food with low water content, often use "Food Desiccant" to make the environment in the food packaging dry, destroying the necessary conditions for the growth and reproduction of mold, in order to achieve the purpose of extending the shelf life of food.

　　4)Temperature

　　The range of temperatures required for the growth and reproduction of various microorganisms are different. The temperature range of adaptation for Halophilic Microorganism is below 20℃, the spoilage of refrigerated foods is mostly caused by these microbes. The temperature range of medium temperature microorganisms is 20~40℃, and most microorganisms in nature belong to this category. High-temperature microorganisms adapt to a temperature range of more than 45℃, such as microorganisms in hot springs. The mildew in common bread, moon cake and other foods belongs to medium-temperature microorganism, so these foods can be put in the refrigerator to extend their shelf life.

　　Through the above introduction we know that mold growth mainly depends on nutrients, oxygen, water, temperature four major living conditions. During the transportation, storage and shelf life of food after leaving the factory, nutrients and temperature are two factors that cannot be controlled artificially. Therefore, the quality of food is mainly controlled by "Oxygen Absorber " and "Food Desiccant". The former controls oxygen and the latter controls water. All kinds of food should use "Oxygen Absorber" or "food desiccant" need to be decided according to the moisture content of the food itself.