Mechanism of freeze-thaw damage in Pseudomonas F8

Pseudomonas F8 was tested for freeze-thaw sensitivity after being washed several times with water. Survival increased to 85% in the fourth wash. Addition of 1% sodium chloride decreased survival to the level obtained when cells were frozen in brain-heart infusion broth. No differences were observed between cells grown at 5 or 23 °C. The freeze-thaw sensitivity of Pseudomonas may be due to the cell's exposure to concentrated medium salts during cooling and warming.