Evaluation of Optoflow Microcyte(R) flow cytometer

Optoflow Microcyte flow cytometer has been evaluated with regard to its user-friendliness and ability to detect different types of bacteria. Bacillus cereus and Escherichia coli are tested at different concentrations and in presence of various contaminants such as wheat flour, icing sugar, baking powder, table salt, melted snow and river water. ToProTM-3 has been used as fluorescent dye. The tested bacteria show characteristic and reproducible fluorescence intensity vs scatter plots, which are little influenced by contaminating compounds except for very high concentrations of table salt. The observed detection limits are in the order of 104 organisms/ml. The may need to be improved for example by selecting other fluorescent dyes and/or different sample preparation techniques. The flow cytometer is characterised by easy handling, small size and an apparently sturdy construction. The contribution of this system in detection of micro organisms is depending on to what extent it is possible to establish a comprehensive library of various types of bacteria, effect of living conditions and potential interfering particulate materials and chemicals.