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NOTE In order to restrict the range of enumeration to a given interval, especially if high numbers of microorganisms are foreseen (see Codex Stan [6]), it is possible to inoculate only the necessary decimal dilutions (at least two successive dilutions) needed to facilitate proper enumeration (see 9.1 and ISO 7218).
注:为了将计数范围限制在给定的时间间隔内,特别是在预见到大量微生物的情况下(参见Codex Stan [6]),可以仅接种必要的小数稀释度(至少两次连续稀释),以便于正确计数(见9.1和ISO 7218)。
Alternatively, apply automated spread preparation techniques, if validated with reference to this international Standard.
或者,如果参照本国际标准进行验证,则应用自动涂抹酱制备技术。

8.6 Duration of the procedure
8.6 程序的持续时间

The time between ending the preparation oi the primary dilution (initial dilution (eady-made) until addition of culture medium shall not exceed 15 min (see Reference [8]).
从结束制备到初级稀释(初始稀释(eady-made))到加入培养基之间的时间不得超过15分钟(参见参考文献[8])。

8.7 Incubation 8.7 孵化

Immediately after solidification of the medium, invert all Petri dishes in the anaerobic culture jar or anaerobic incubator (6.1) and incubate at for .
培养基凝固后,立即将所有培养皿倒置在厌氧培养罐或厌氧培养箱(6.1)中,并在 for 孵育。

8.8 Counting of the colonies
8.8 菌落的计数

Count the colonies after incubation by considering only the diution steps within the countable area [i.e. dilutions for which the expected average count per plate, CFU (see also ISO 7218)].
孵育后通过仅考虑可计数区域内的稀释步骤来计数菌落 [即每板预期平均计数的稀释液, CFU(另见 ISO 7218)]。
Count all plates of the selected dilutions by considering all colonies on the plate directly after completion of the incubation.
孵育完成后,通过直接考虑板上的所有菌落来计算所选稀释液的所有板。
Examine the plates under subdued light. To facilitate counting, use the suitable colony-counting equipment (6.3). Avoid mistaken particles of undissolved sample or precipitated matter in dishes for pinpoint colonies. Examine doubtful objects carefully, using a lens of higher magnification if required, to distinguish colonies from foreign matter.
在柔和的光线下检查板。为便于计数,请使用合适的菌落计数设备 (6.3)。避免在培养皿中误入未溶解的样品颗粒或沉淀物,以获得精确的菌落。仔细检查可疑物体,如果需要,请使用更高放大倍率的镜头,以区分菌落和异物。
After incubation, immediately examine the dishes, fossible. Alternatively, store the dishes in the refrigerator for 48 h maximum (see ISO 7218).
孵育后,立即检查培养皿,可旋转。或者,将菜肴存放在冰箱中最多 48 小时(参见 ISO 7218)。

8.9 Reading of the Petri dishes - confirmation
8.9 读取培养皿 - 确认

Identify bifidobacterial colonies by their whttish colour. Select typical colonies (see 3.1) from the plates used for counting and examine microscopically
通过白色识别双歧杆菌菌落。从用于计数的板中选择典型的菌落(见3.1)并进行显微镜检查
Optionally, a F6PPK-assay can be performed to confirm the results (see References [14][15]).
可选地,可以进行F6PPK测定以确认结果(参见参考文献[14][15])。
NOTE Some bifidobacterial strains can show differing colony sizes and appearances on the same plate. Most bifidobacterial colonies give off an acetic acid odour.
注意:一些双歧杆菌菌株可以在同一平板上显示不同的菌落大小和外观。大多数双歧杆菌菌落散发出醋酸气味。

9 Calculation and expyession of results
9 结果的计算和计算

9.1 Calculation 9.1 计算

Use all counts from plates originating from the dilution steps within the countable area as obtained in 8.7. The countable area includes all dilutions for which the expected average count per plate, .
使用源自可计数区域内稀释步骤的板的所有计数,如8.7中所得。可计数面积包括每个板的预期平均计数的所有稀释液
Calculate the number of CFU of presumptive bifidobacteria per gram of product, , using the equation
计算每克产品中推定的双歧杆菌的 CFU 数, 使用以下公式
where 哪里
is the sum of colonies counted on all dishes retained (8.8);
是所有保留的培养皿上计算的菌落总和 (8.8);
is the number of dishes retained in the first countable dilution;
是第一可数稀释液中保留的培养皿数量;
is the number of dishes retained in the second dilution;
是第二次稀释中保留的培养皿数量;
is the number of dishes retained in the third dilution;
是第三次稀释中保留的培养皿数量;
is the dilution factor corresponding to the first countable dilution retained.
是对应于保留的第一个可计数稀释的稀释因子。
If there are only two countable dilutions, modify the equation to
如果只有两个可计数的稀释度,则将公式修改为
Determine the reliability of the colony counts obtained from parallel plates and subsequent dilution steps according to ISO 14461-2||DF 169-2. For the calcularion of the result, use only reliable counts (see also ISO 7218).
根据 ISO 14461-2 确定从平行板获得的菌落计数和后续稀释步骤的可靠性||DF 169-2型。对于结果的计算,仅使用可靠的计数(另请参阅 ISO 7218)。

9.2 Expression of results
9.2 结果表达

Express the results to two significant figures as the number of CFU of bifidobacteria per gram of product, representing a number between 1,0 and 9,0 multiplied by the appropriate power of 10 . For the validity of results see 10.4 .
将结果表示为两个有效数字,即每克产品的双歧杆菌 CFU 数,表示 1,0 和 9,0 之间的数字乘以 10 的适当幂。有关结果的有效性,请参见 10.4 。
If the last figure is below 5, the precedjing figure is not modified. If the last figure is 5 or more, increase the preceding figure by one unit. Proceed stepwise until two significant figures are obtained (see ISO 7218).
如果最后一个数字小于 5,则不会修改前面的数字。如果最后一个数字是 5 或更多,则将前一个数字增加一个单位。逐步进行,直到获得两个有效数字(参见 ISO 7218)。
EXAMPLE 1 Assuming that a coun of bifidobacteria on the medium gave the results shown below (two Petri dishes per dilution incubated), the final result can be calculaled as shown.
实施例 1 假设培养基上的一组双歧杆菌得到如下所示的结果(每次孵育稀释液两个培养皿),最终结果可以如图所示计算。
Table 1-Example 1 表1-示例1
Dilution 稀释 Plate 1 板 1 Plate 2 板块 2
D4 (decimal dilution 10-4)
D4(十进制稀释度 10-4)
300 298
D5 (decimal dilution 10-5)
D5(十进制稀释度 10-5)
30 25
D6 (decimal dilution 10-6)
D6(十进制稀释度 10-6)
2 3
Insertion of the figures into Equalion (1) gives
将数字插入均衡 (1) 可得到