The effect of growth phase, cryoprotectants and freezing rates on the survival of selected micro-organisms during freezing and thawing

The effect of growth phase of cells, cryoprotectant agents and freezing rat e on the survival of selected micro-organisms (Bacillus cereus, Lactobacill us plantarum, Escherichia coli, Pseudomonas fluorescens, Saccharomyces cere visiae, Kluyveromyces lactis, Candida utilis, Mucor racemosus, Aspergillus niger) during freezing and thawing was studied. In cases where significant differences were observed stationary phase cells always survived better tha n exponential phase ones, while of the two cryoprotectant agents studied, h orse serum + inositol was always superior to skimmed milk powder + inositol . The effect of freezing rate was different among the studied micro-organis ms.