The objectives of this study were: to assess the efficiency of high hydrostatic pressure or ultra-high pressure homogenization against Mycobacterium smegmatis in milk and to discuss whether M. smegmatis can be considered a suitable surrogate for other Mycobacterium spp. in high pressure inactivation trials using milk. Three strains of this specie (CECT 3017, 3020 and 3032) were independently inoculated into both skimmed (0.2% fat) and whole milk (3.4% fat) at an approximate load of 6.5 Log CFU/ml and submitted to HHP treatments at 300, 400 or 500 MPa for 10 m at 6°C and 20°C. Evolution of the surviving cells of the inoculated strains was evaluated analysing milk immediately after the treatments and after 5 and 8 d of storage at 6°C. HHP treatments at 300 MPa were seldom efficient at inactivating M. smegmatis strains, but lethality increased with pressure applied in all cases. Generation of sub-lethal injured cells was observed only after 400 MPa treatments since inactivation at 500 MPa was shown to be complete. Significant differences were not observed due to either temperature of treatment or fat content of milk, except for strain CECT3032, which was shown to be the most sensitive to HHP treatments. Milk inoculated with strain CECT3017 was submitted to ultra-high pressure homogenization (UHPH) treatments at 200, 300 and 400 MPa. Maximum reductions were obtained after 300 and 400 MPa treatments, although less than 3.50 Log CFU/ml were inactivated. UHPH did not cause significant number of injured cells. The usefulness of this species as a marker for pressure-based processing seems limited since it showed greater sensitivity than some pathogenic species including other Mycobacteria reported in previous studies.

中文翻译：

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评价耻垢分枝杆菌作为高静水压力和超高压均质处理在牛奶中类似巴氏杀菌的效果的指标

本研究的目的是：评估高静水压力或超高压均质化的效率耻垢分枝杆菌在牛奶中并讨论是否耻垢分枝杆菌可以被认为是其他合适的替代品分枝杆菌spp. 在使用牛奶的高压灭活试验中。该物种的三个菌株（CECT 3017、3020 和 3032）以大约 6.5 Log CFU/ml 的负荷分别接种到脱脂牛奶（0.2% 脂肪）和全脂牛奶（3.4% 脂肪）中，并在 300 时进行 HHP 处理， 400 或 500 MPa，在 6°C 和 20°C 下 10 m。在处理后以及在 6°C 下储存 5 天和 8 天后立即分析牛奶，评估接种菌株的存活细胞的进化。300 MPa 的 HHP 处理在灭活方面很少有效耻垢分枝杆菌菌株，但在所有情况下，随着压力的施加，杀伤力增加。仅在 400 MPa 处理后才观察到亚致死损伤细胞的产生，因为在 500 MPa 下的失活显示是完全的。由于处理温度或牛奶的脂肪含量没有观察到显着差异，除了菌株 CECT3032，它被证明对 HHP 处理最敏感。用菌株 CECT3017 接种的牛奶在 200、300 和 400 MPa 下进行超高压均质 (UHPH) 处理。在 300 和 400 MPa 处理后获得了最大的减少，尽管小于 3.50 Log CFU/ml 被灭活。UHPH 不会导致大量受损细胞。分枝杆菌在以往的研究中报道。