HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

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 Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Harmon, L. G. Articles by Nelson, F. E. Search for Related Content PubMed Articles by Harmon, L. G. Articles by Nelson, F. E.

Interrelationships of Microorganisms in Cream. III. Candida pseudotropicalis, Aerobacter aerogenes, and Streptococcus lactis¹

Department of Dairy Industry, Iowa State College, Ames

ABSTRACT

1. Candida pseudotropicalis and Aerobacter aerogenes, individually and in combination with Streptococcus lactis, were inoculated into sterile cream and incubated at 10°, 20°, and 30° C. for 10 days or until the cream was no longer of acceptable commercial quality, whichever occurred first.
   
2. Neither of the organisms, individually or in combination with S. lactis, produced as much as 400 mg. of W.I.A. per 100 g. of fat.
   
3. C. pseudotropicalis, alone or in combination with S. lactis, and A. aerogenes alone caused negligible increases in free tryptophan. The combination of A. aerogenes and S. lactis produced 32 p.p.m. of free tryptophan in 3 days at 20° C. and 15 p.p.m. in 1 day at 30° C.
   
4. At 20° C. the combination of S. lactis with C. pseudotropicalis diminished the rate of increase and maximum C. pseudotropicalis population attained. The presence of A. aerogenes caused a reduction in the rate of increase and maximum population attained by S. lactis.
   
5. At 20° and 30° C., addition of S. lactis did not alter the rate of organoleptically determined deterioration caused by C. pseudotropicalis, but at 10° C. the presence of S. lactis extended the commercial life of cream containing C. pseudotropicalis. Deterioration in organoleptic quality appeared to be more closely related to increases in organism populations than to chemical factors studied.
   

¹ Journal paper No. J-2939 of the Iowa Agricultural Experiment Station, Ames. Project No. 1050.

² Present address: Department of Dairy, Michigan State University, East Lansing.