Spray Drying, Freeze Drying, or Freezing of Three Different Lactic Acid Bacteria Species


  • This research was funded by Dairy Management Inc. through the Wisconsin Center for Dairy Research. Dr. Mark Johnson, Ms. Julie Johnson, and Ms. Beth Jones provided invaluable assistance with species procurement, cultivation and enumeration procedures.


Lactococcus lactis ssp. cremoris D11, Lactobacillus casei ssp. pseudo-plantarum UL137, and Streptococcus thermophilus CH3TH, were separately frozen, freeze dried or spray dried, and tested for survival and lactic acid production before and after processing. Virtually all cells survived freezing. Of the survivors, 60 to 70% survived the dehydration step of freeze drying. In contrast to freezing and freeze drying, spray drying caused considerable delay in lactic acid production and reduction in survival. After spray drying, survival was greatest for S. thermophilus and lowest for Lc. cremoris.