The total number of colonies refers to the growth of samples per gram (per milliliter) under certain conditions (such as oxygen demand, nutritional conditions, pH, culture temperature and time, etc.) Total bacterial colonies 。 According to the national standard method, that is, under aerobic condition, the total number of bacterial colonies that can grow on the ordinary nutrient agar plate when cultured at 37 ℃ for 48h. Therefore, anaerobic or microaerobic bacteria, bacteria with special nutritional requirements and non mesophilic bacteria are difficult to reproduce and grow because the existing conditions can not meet their physiological needs. Therefore, the total number of colonies does not represent the actual total number of bacteria, and the total number of colonies can not distinguish the types of bacteria, so it is sometimes referred to as the number of miscellaneous bacteria, aerobic bacteria, etc.
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