Aims: To assess the protective effect of gum acacia (GA) on the performance of Lactobacillus paracasei NFBC 338 during spray-drying, subsequent storage and exposure of the culture to porcine gastric juice. Methods and Results: For these studies, Lact. paracasei NFBC 338 was grown in a mixture of reconstituted skim milk (10% w/v) and GA (10% w/v) to mid log phase and spray-dried at outlet temperatures between 95 and 105 degreesC. On spray drying at the higher air outlet temperature of 100-105 degreesC, the GA-treated culture displayed 10-fold greater survival than control cells. Probiotic lactobacilli in GA-containing powders also survived dramatically better than untreated cultures during storage at 4-30 degreesC for 4 weeks. A 20-fold better survival of the probiotic culture in GA-containing powders was obtained during storage at 4 degreesC while, at 15 and 30 degreesC, greater than 1000-fold higher survival was obtained. Furthermore, the viability of probiotic lactobacilli in GA-containing powders was 100-fold higher when exposed to porcine gastric juice over 120 min compared with the control spray-dried culture. Conclusions: The data indicate that GA has applications in the protection of probiotic cultures during drying, storage and gastric transit. Significance and Impact of the Study: Gum acacia treatment for the manufacture of probiotic-containing powders should result in more efficient probiotic delivery to the host gastrointestinal tract.