Cold lability of Bacillus cereus bacteriophage CP 51

Phage CP 51 was rapidly inactivated when stored at the usual refrigerator temperatures (2 to 4 C) and even more rapidly when exposed to 0 C. The loss in viability resulting from exposure to cold appeared to correlate with the increase in number of phage particles having contracted tails. High concentrations (0.01 M) of Mg²⁺, Ca²⁺ or Mn²⁺ stabilzed the phage considerably, but even in the presence of these divalent cations, it was much less stable at 0 C than at 15 C.