不同检测时间对原料乳中嗜冷菌检测结果的影响

目的]为提高原料乳中嗜冷菌检测的准确性，制定更加合理的嗜冷菌检测标准流程。方法]本试验根据《NY/T 1331—2007乳与乳制品中嗜冷菌、需氧芽孢及嗜热需氧芽孢数的测定》中的MPC中平板计数法对新疆地区10个不同养殖模式牧场，共计120份原料乳样品在不同检测时间下的嗜冷菌水平进行检测。结果]在10-2和10-3两个稀释梯度下，3个不同模式牧场嗜冷菌检测结果均随着检测间隔时间的增加而增加，其中现代化牧场和传统牧场嗜冷菌即时检测结果与间隔12 h和24 h的检测结果均存在显著性差异（P<0.05），养殖小区嗜冷菌即时检测和间隔24 h差异显著（P<0.05），间隔12 h检测结果与即时检测和间隔24 h检测结果无显著差异（P>0.05）。结论]检测间隔时间对原料乳中嗜冷菌检测结果存在影响，样品检测间隔时间越久，最终检测结果越大，导致最终结果不具有准确性和说服性。

Effect of Different Detection Time on the Detection Results of Psychrophilein Raw Milk

Objective]In order to improve the accuracy of the detection of psychrophile bacteria in raw milk,a more reasonable standard process for the detection of psychrophile bacteria was developed.Method]In this experiment,according to the MPC in NY/T 1331-2007 Determination of the Number of psychrophile Bacteria,Aerobic Spores and Thermophilic Aerobic Spores in Milk and Dairy Products,the level of psychrophile bacteria in a total of 120 raw milk samples from ten pastures with different cultivation modes in Xinjiang were detected at different detection times. Result] Under the two dilution gradients of 10^-2 and 10^-3,the results of psychrophile bacteria in the three pastures of different modes increased with the increase of the detection interval,and there were significant differences between the results of psychrophile bacteria in the modern pastures and traditional large-scale pastures and the detection results of psychrophile bacteria in the 12 h and 24 h intervals（P<0.05）. There were significant differences between the immediate detection and 24 h interval of psychrophile bacteria（P<0.05）,but there was no significant difference between the detection results of 12 h interval and immediate detection and 24 h interval（P>0.05）.Conclusion]The research results showed that the detection interval had an impact on the detection results of psychrophile bacteria in raw milk. The longer the detection interval,the larger the final detection results,resulting in the final results were not accurate and persuasive.