Percentages of encapsulated cells found viable after 30 days frozen storage were about 54 and 69 for L. casei and B. lactis, respectively (Fig. 4). Percentages of survival among the free cells were much lower, about 22 and 40 for L. casei and B. lactis, respectively. Cells of L. casei were much larger (1.5 3 lm) than those of B. lactis (0.5 1.5 lm) (figures not shown) suggesting that the larger cells were much more susceptible to mechanical damage than smaller cells. Entrapped cells survived freezing better than free cells (P < 0.05) when compared within the same strain. Probiotics survived 30% more when they were encapsulated in calcium alginate than when they were not encapsulated. Protection by microencapsulation was significant (P < 0.05) both in the ice cream freezer and during frozen storage.