This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Speck, M. L. Articles by Koburger, J. A. Search for Related Content PubMed Articles by Speck, M. L. Articles by Koburger, J. A. Agricola Articles by Speck, M. L. Articles by Koburger, J. A.

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1962 November; 10(6): 496-499

Activation of Dry Starter Cultures in Milk¹

Department of Food Science, North Carolina State College, Raleigh, North Carolina

ABSTRACT

The revitalization of mixed strain dried starter cultures at 22 and 32 C in sterile skim milk was materially accelerated when the substrate was fortified with 0.2% pancreas-extract solids. At 22 C, all cultures grew up satisfactorily in 18 hr, and in unfortified milk none of the cultures reached comparable growth in this period. When the cultures were grown at 32 C, the dried cultures developed adequately in 7.5 hr, but required 9 to 10 hr in plain milk. Culture growth was enhanced in milk containing pancreas extract to the extent that the amount of dried culture required to produce adequate acidity in normal incubation times could be markedly reduced. At 32 C, certain cultures could be reduced to 12.5% of recommended amounts, and at 22 C certain ones could be reduced by 50%. Revitalization of the dried cultures in milk containing pancreas extract did not affect the growth of subcultures in plain milk. Also, when dried cultures initiated growth in fortified milk at 32 C their subsequent growth at 22 C in milk alone was not affected. The faster rate of culture growth in milk containing pancreas extract should permit, with more certainty, the establishment of active mother and bulk starters. Furthermore, economy of dried cultures, as well as of time, could be realized by the use of fortified milk.

¹ Contribution from the Department of Food Science, North Carolina Agricultural Experiment Station, Raleigh. Published with the approval of the Director of Research as Paper no. 1443 of the Journal Series.