The aim of this study was to monitor viability of probiotic Lactobacillus paracasei NFBC 338 during: (a) two-stage yoghurt fermentation with starter cultures Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, (b) following spray drying, and (c) during storage for 42 days. During the initial fermentation phase (10 h), probiotic Lactobacillus numbers increased 7-fold to 3.9 x 10(9) cfu g(-1) and these numbers were maintained during fermentation for a further 3 h in the presence of the yoghurt starters. Following spray-drying, the probiotic culture survived best, followed by S. thermophilus and L delbrueckii subsp. bulgaricus (yielding 3.4 x 10(8), 1.2 x 10(8) and 4.0 x 10(5) cfu g(-1) powder, respectively). L paracasei NFBC 338 and S. thermophilus were stable during storage at 4 degrees C and 15 degrees C (for 42 days) with viable counts exceeding 10(7) cfu g(-1), while viability of L. detbrueckii subsp. bulgaricus decreased considerably throughout storage. (C) 2009 Elsevier Ltd. All rights reserved.