A frozen concentrate of Lactobacillus acidophilus was used as inoculum for milk solids-not-fat (MSNF) reconstituted to 25 and 40% solids. Initial count of the two milks was 1.2 × 109 and 7.0 × 108 CFU/g of solids, respectively. Sublots of these two concentrates were spray-dried at 85-, 80-, and 75-C exit air temperature in a Coulter/Townley pilot dryer (vertical, venturi nozzle spray system). Survival of L. acidophilus was greatest at the lowest outlet air temperature investigated, and in the milk of lower solids content. At 75-C exit air temperature the count following drying was 2.6 × 107 per gram of solids at 40 percent solids, and 9.8 × 107 per gram of solids at 25% solids. Percent survival after 30 days storage under nitrogen at 4 C was 1.29 and 4.17, respectively, for the two solids levels.
1Paper No. 10327, Scientific Journal Series, Minnesota Agricultural Experiment Station, St. Paul.
2Current address: Centro Tecnologico de la Leche, Universidad Austral, casilla 47, Valdivia, Chile, South America.