Survival of Streptococcus salivatius subsp. thermophilus and Lactobacillus debnceckii subsp. bulgariclcs was determined under various processing conditions for spray drying. Numbers of both microorganisms decreased with increased outlet or inlet air temperature, and atomizing air pressure. Outlet air temperature was a major parameter affectingnumber of survivors. Suitable-conditions were inlet air 160°C outlet air 60°C. atomizinz air nressure 98 kPa. hot air flow 0.28 m3/ min, and feed temperatuG 3tiC. Spray-dried yogurt powder showed lower survival for S. thermophilus and similar survival for L. bulgaricw as compared to freeze-dried powder.

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