环酸芽孢杆菌的分离及其不同生长参数的影响。
Isolation of Alicyclobacillus and the influence of different growth parameters.
机构信息
Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch) 7602, South Africa.
出版信息
Int J Food Microbiol. 2011 Mar 15;146(1):63-8. doi: 10.1016/j.ijfoodmicro.2011.02.002. Epub 2011 Mar 2.
Alicyclobacillus species are thermo-acidophilic, endospore-forming bacteria that are able to survive pasteurisation and have been implicated in a number of spoilage incidents involving acidic foods and beverages. The aim of this study was to compare three isolation methods used for the detection of Alicyclobacillus acidoterrestris and to investigate the influence of incubation temperature on the growth of A. acidoterrestris and A. acidocaldarius. Peach juice samples inoculated with A. acidoterrestris K47 were analysed using either the International Federation of Fruit Juice Producers (IFU) Method No. 12 (Method A), which involved spread plating onto Bacillus acidoterrestris (BAT) agar at pH 4.0; Method B, which involved pour plating using potato dextrose agar (PDA) at pH 3.7; or Method C, which made use of membrane filtration followed by incubation on K agar at pH 3.7. The performance of the three methods differed significantly, with the IFU Method No. 12 recovering the highest percentage of cells at 75.97%, followed by Method B at 66.79% and Method C at 3.43%. These findings strengthen the proposal of the IFU for the use of the IFU Method No. 12 as a standard international method for the detection of Alicyclobacillus. To investigate the effect on growth of different incubation temperatures A. acidoterrestris (three strains) and A. acidocaldarius (two strains) were incubated at either 45 °C or 25 °C. Growth at 25°C was slower and maximum cell concentrations were lower (1 x 10⁵-10⁶ cfu/mL compared to 1 x 10⁷-10⁸ cfu/mL) than at 45 °C for A. acidoterrestris. A. acidocaldarius was unable to grow at 25°C and cell concentrations decreased by 1-2 logs. Since a growth temperature of 25 °C could not inhibit growth of A. acidoterrestris, cooling to room temperature (20°-25 °C) is not an effective control measure for A. acidoterrestris inhibition.
环状芽孢杆菌是一种嗜热嗜酸、产芽孢的细菌，能够在巴氏消毒后存活，并与许多涉及酸性食品和饮料的变质事件有关。本研究的目的是比较三种用于检测耐热嗜酸菌和耐热环酸芽孢杆菌的分离方法，并研究培养温度对耐热嗜酸菌和耐热环酸芽孢杆菌生长的影响。将接种了耐热嗜酸菌 K47 的桃汁样品分别用国际果汁生产者联合会（IFU）方法 12（方法 A）、方法 B 和方法 C 进行分析。方法 A 是在 pH4.0 的 Bacillus acidoterrestris（BAT）琼脂上进行划线分离；方法 B 是在 pH3.7 的土豆葡萄糖琼脂（PDA）上进行倾析分离；方法 C 是利用膜过滤后在 pH3.7 的 K 琼脂上进行培养。这三种方法的性能差异显著，IFU 方法 12 回收的细胞百分比最高，为 75.97%，其次是方法 B，为 66.79%，方法 C 为 3.43%。这些发现支持了 IFU 提出的使用 IFU 方法 12 作为耐热嗜酸菌检测的国际标准方法的建议。为了研究不同培养温度对生长的影响，将耐热嗜酸菌（三株）和耐热环酸芽孢杆菌（两株）分别在 45°C 或 25°C 下培养。在 25°C 下生长较慢，最大细胞浓度较低（1x10⁵-10⁶cfu/mL 相比 1x10⁷-10⁸cfu/mL）比 45°C 下的耐热嗜酸菌。耐热环酸芽孢杆菌不能在 25°C 下生长，细胞浓度下降 1-2 个对数级。由于 25°C 的生长温度不能抑制耐热嗜酸菌的生长，冷却至室温（20°C-25°C）不是抑制耐热嗜酸菌的有效控制措施。
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