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目的研究乳酸链球菌素(Nisin)对原料乳中菌落总数的影响。方法冷藏温度(4℃)和室温(20℃)条件下在原料乳中添加不同浓度的乳酸链球菌素(Nisin),计数原料乳中的细菌总数,分析Nisin添加浓度以及储存温度、时间对原料乳中菌落总数的影响。结果与对照组比较,添加Nisin的原料乳菌落总数显著减少,且随着Nisin浓度的升高,Nisin的抑菌效果增强;细菌在4℃条件下的繁殖速度比在20℃时慢;超过一定的储存时间内,即便添加Nisin并4℃冷藏,原料乳中的细菌总数仍会快速增长。结论在4℃的条件下,国家允许添加的范围内添加500 mg/L浓度的Nisin在一定的储存时间内可有效控制原料乳菌落总数的增长。
Objective To study the effect of nisin on the total number of colonies in raw milk. Methods Different concentrations of Nisin were added into the raw milk under the condition of refrigerating temperature (4 ℃) and room temperature (20 ℃). The total number of bacteria in the raw milk was counted. The concentration of Nisin, storage temperature and time were analyzed. Effect of total number of colonies in milk. Results Compared with the control group, the total count of raw milk added with Nisin significantly decreased, and the antibacterial activity of Nisin increased with the increase of Nisin concentration. The rate of bacteria proliferation at 4 ℃ was slower than that at 20 ℃. Of the storage time, the total amount of bacteria in the raw milk will grow rapidly even if Nisin is added and refrigerated at 4 ° C. Conclusion Under the condition of 4 ℃, the addition of 500 mg / L Nisin in the range allowed by the country can effectively control the growth of total count of raw milk in a certain storage time.