The release of cellular constituents of Lactobacillus lactis by freezing and freeze-drying

Lactobacillus lactis cell was markedly damaged when shocked by freezing and freeze-drying. The supernatant of shocked cells in 1％ phosphate buffer (pH7.3) showed a maximum u.v. absorption spectra at 260nm after further incubation for 90min at $37-^{\circ}C.$ The leakage of cellular constituents by shocking could be prevented by dimethyl sulfoxide, glycerol, dextrose and $MgCl_2.$ Among them, $MgCl_2$ showed the preventing effect before and after freezing wh-ereas the rests, only before the treatment. This leakage was proved not to be related to the cellular repairing mechanism.