计数标准微球分散及浓度对酿酒酵母计数的比较

针对计数标准微球在微生物计数中的微球聚集、使用浓度及统计数量进行分析比较。以计数标准微球和酿酒酵母ATCC9080为实验对象，研究了Tween 20、Tween 80对计数标准微球的分散效果以及标准微球浓度、统计数量对酿酒酵母计数结果的影响，并将标准微球计数结果与平板计数结果进行比较。实验表明计数标准微球在0.08% Tween 20或0.06% Tween 80中的分散效果适宜，可使分散指数为3.30。对每毫升105、106、107个酿酒酵母悬液进行计数时，统计的标准微球总数依次应不小于2 000、1 500、1 000个，统计的细胞总数分别应不小于200、400、2 600个。在每毫升105~107个酿酒酵母浓度范围，以每毫升106个标准微球最适宜，且对酿酒酵母的计数结果与平板计数结果呈线性关系（R2=0.996 9）。结果表明Tween 20或Tween 80可有效分散计数标准微球，采用分散的、适宜浓度的计数标准微球可对微生物悬液进行准确计数，明确了计数标准微球用于微生物计数的适宜参数，补充 GB/T 39730-2020标准微球使用条件。

Comparison of Counting Standard Microsphere Dispersion and Concentration for enumerating Saccharomyces cerevisiae

The concentration and statistical numbers of counting standard microspheres used for cell counting of the Saccharomyces cerevisiae strain (ATCC9080) were selected for analyzing the effects of microsphere aggregation. The dispersion, concentration, and statistical numbers of microspheres in Tween 20 or Tween 80 suspension for S. cerevisiae counting were evaluated. In addition, we determined the linearity between standard microsphere counting and plate counting. Our study showed that the dispersion of microspheres in 0.08% Tween 20 or 0.06% Tween 80 suspension was suitable, with a dispersion index of 3.30. For counting 105, 106, and 107 cells/mL of S. cerevisiae, the total statistical numbers of standard microspheres should not be less than 2 000, 1 500, and 1 000, respectively. In addition, the total statistical numbers of cells should not be fewer than 200, 400, and 2 600. At 105 to 107 cells/mL of S. cerevisiae, the counting results by standard microspheres were consistent with those of the plate counting (R2=0.996 9), with 106 beads/mL of standard microsphere being the most suitable concentration. Our results indicated the standard microspheres could be effectively dispersed by Tween 20 or Tween 80. Hence, microbial cells in suspension can be accurately counted by using an appropriate concentration of dispersed standard microspheres. The suitable parameters of the standard microspheres for microbial counting were identified to provide the application conditions of standard microspheres in GB/T 39730-2020.