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Updated: Nov 6, 2025
Formulations for Freeze-drying of Bacteria and Their Influence on Cell Survival
Published on: August 3, 2013
Impact of Oscillating Magnetic Field Assisted Freezing on Lactobacillus plantarum Viability: Effects of Frozen
L Cartagena1, E Puertolas2, I Martinez de Maranon2
1AZTI, Food Research Division. Parque Tecnologico de Bizkaia. Astondo Bidea, Edificio Derio (Bizkaia), Spain. epuertolas@azti.es.
Background:
Oscillating magnetic field (OMF) assisted freezing has been proposed for improving the frozen preservation of biological materials. However, contradictory results have been reported on foods, tissues and cells, and so doubts exist in its actual benefit.
Objective:
To study the effect of OMF-assisted freezing on the viability of fermentation starter Lactobacillus plantarum.
Materials And Methods:
L. plantarum bacteria were frozen in a batch air blast freezer (-20ºC, 5 m s-1) by OMF-assisted freezing (0.57 mT). Bacterial viability was examined after 60 days of frozen storage and 5 freeze-thaw cycles.
Results:
OMF showed no statistically significant effects (P > 0.05) in key freezing curve characteristics, refuting Cell Alive System (CAS) technology claims. OMF-assisted freezing did not improve bacterial preservation.
Conclusion:
There was no effect of the application of the maximum OMF (0.57 mT) on cell viability independently of the frozen storage time (up to 60 days) and freeze-thaw repetitions (up to 5 cycles).
