Contamination by spores is often the cause of fungal food spoilage. Some distinct strains of the food spoilage fungus Paecilomyces variotii are able to produce airborne conidia that are more heat-resistant than similar species. These ellipsoid asexual spores can vary in size between strains, but also within strains. Here, we compared four measurement techniques to measure conidia size and distribution of five heat-sensitive and five heat-resistant P. variotii strains. Light microscopy (LM), Scanning Electron Microscopy (SEM) and Coulter Counter (CC) were used to measure and compare the spherical equivalent diameter, while CC and flow cytometry were used to study spore size distributions. The flow cytometry data was useful to study spore size distributions, but only relative spore sizes were obtained. There was no statistic difference between the method used of spore size measurement between LM, SEM and CC, but spore size was significantly different between strains with a 2.4-fold volume difference between the extremes. Various size distribution and shape parameters were correlated with conidial heat resistance. We found significant correlations in mean spore size, aspect ratio, roundness and skewness in relation to heat resistance, which suggests that these parameters are indicative for the conidial heat resistance of a P. variotii strain.

孢子污染通常是真菌食物变质的原因。食物腐败真菌Paecilomyces variotii的一些独特菌株能够产生比相似物种更耐热的空中分生孢子。这些椭圆体无性孢子的大小在菌株之间也可以在菌株内变化。在这里，我们比较了四种测量技术，以测量五个热敏性和五个耐热性天花粉虱的分生孢子大小和分布。株。光学显微镜（LM），扫描电子显微镜（SEM）和库尔特计数器（CC）用于测量和比较球形当量直径，而CC和流式细胞仪用于研究孢子大小分布。流式细胞仪数据可用于研究孢子大小分布，但仅获得相对孢子大小。LM，SEM和CC之间使用的孢子大小测量方法之间没有统计学差异，但是菌株之间的孢子大小显着不同，极端之间的体积差为2.4倍。各种尺寸分布和形状参数与分形耐热性相关。我们发现平均孢子大小，长宽比，圆度和偏度与耐热性之间存在显着相关性，P. variotii菌株。