Hammer P, Richter E, Rüsch-Gerdes S, Walte H-G C, Matzen S, Kiesner C
Department of Safety and Quality of Milk and Fish Products, Max Rubner-Institute, Federal Research Institute of Nutrition and Food, 24103 Kiel, Germany.
National Reference Center for Mycobacteria, Forschungszentrum Borstel, 23845 Borstel, Germany.
J Dairy Sci. 2015 Mar;98(3):1634-9. doi: 10.3168/jds.2014-8939. Epub 2015 Jan 15.
Experiments to determine the efficacy of high temperature, short time (HTST) pasteurization of milk in terms of inactivation of pathogenic microorganisms were mainly performed between 1930 and 1960. Among the target organisms were Mycobacterium bovis and Mycobacterium tuberculosis. As a result, the Codex Alimentarius prescribes that HTST treatment of milk should lead to a significant reduction of pathogenic microorganisms during milk pasteurization. Due to the development of improved methods for the detection of survivors and of more advanced heating technology, verification of this requirement seemed to be necessary. To address recent outbreaks of tuberculosis in cattle caused by M. bovis ssp. caprae (M. caprae) in the southern regions of Germany, this organism was tested and compared with M. bovis ssp. bovis (M. bovis). Experiments were performed in a pilot plant for HTST pasteurization of milk with 3 strains of M. caprae and 1 strain of M. bovis. In preliminary trials at a fixed holding time of 25 s, the temperature at which significant inactivation occurred was 62.5°C for all strains. To determine D-values (decimal reduction times) for the inactivation kinetics, the strains were tested at 65, 62.5, and 60°C at holding times of 16.5, 25, and 35 s. At 65°C, the D-values of all strains ranged from 6.8 to 7.8 s, and at 62.5°C, D-values ranged from 14.5 to 18.1 s. Low inactivation was observed at 60°C. When the low slope of the inactivation curve allowed calculation of a D-value, these ranged from 40.8 to 129.9 s. In terms of log10 reductions, the highest values for all strains were 4.1 to 4.9 log at 65°C, with a holding time of 35 s. The tested strains of M. caprae and M. bovis showed similar low resistance to heat. Standard HTST treatment should result in a high reduction of these organisms and thus the requirements of the Codex Alimentarius for inactivation of pathogens by this process are far exceeded.
确定高温短时（HTST）巴氏杀菌法对牛奶中致病微生物的灭活效果的实验主要在1930年至1960年间进行。目标微生物包括牛分枝杆菌和结核分枝杆菌。因此，食品法典规定，牛奶的HTST处理应在牛奶巴氏杀菌过程中使致病微生物显著减少。由于检测存活菌的改进方法和更先进加热技术的发展，似乎有必要对这一要求进行验证。为应对德国南部地区由牛分枝杆菌山羊亚种（山羊分枝杆菌）引起的牛结核病近期疫情，对该菌株进行了测试，并与牛分枝杆菌牛亚种（牛分枝杆菌）进行了比较。用3株山羊分枝杆菌和1株牛分枝杆菌在牛奶HTST巴氏杀菌中试装置中进行了实验。在固定保温时间为25秒的初步试验中，所有菌株发生显著灭活的温度为62.5℃。为了确定灭活动力学的D值（十进制减少时间），在保温时间为16.5、25和35秒时，在65、62.5和60℃下对菌株进行了测试。在65℃时，所有菌株的D值范围为6.8至7.8秒，在62.5℃时，D值范围为14.5至18.1秒。在60℃时观察到灭活率较低。当灭活曲线的低斜率允许计算D值时，这些值范围为40.8至129.9秒。就log10减少量而言，所有菌株在65℃、保温时间为35秒时的最高值为4.1至4.9 log。所测试的山羊分枝杆菌和牛分枝杆菌菌株对热表现出相似的低抗性。标准的HTST处理应能使这些微生物大量减少，因此食品法典对通过该过程灭活病原体的要求被大大超过。
