乳汁在消毒、浓缩干燥过程中，微生物的数量和种类构成有很大变化，大部分微生物受热死亡，这时，乳粉中的细菌多为耐热的和厌氧的细菌。市售乳粉多采用复合塑料袋包装，由于这种包装使乳粉处于真空．缺氧状态，对厌氧菌是一个良好的厌氧环境。为了解保质期内乳粉中细菌总数、 Milk in the disinfection, concentration and drying process, the number and type of microorganisms have greatly changed the composition, most of the microbes die of heat, then, the milk powder bacteria are mostly heat-resistant and anaerobic bacteria. Commercial milk powder and more use of plastic bags, as a result of this packaging milk powder in a vacuum. Anoxic, anaerobic bacteria is a good anaerobic environment. To understand the shelf life of milk in the total number of bacteria,