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 Arne Hansen, P. Search for Related Content PubMed Articles by Arne Hansen, P.

A Study in Cheese Ripening. The Influence of Auto-Lyzed Cells of Streptococcus Cremoris and Streptococcis Lactis on the Development of Lactobacillus Casei

Department of Bacteriology, Georgetown University School of Medicine, Washington, D. C.

ABSTRACT

There is a gradual change in the bacterial flora of cheese during the process of ripening. In the hard cheeses, which have not been heated to a high temperature, Streptococcus lactis and Streptococcus cremoris are predominant at first, later being replaced by Lactobacillus casei (Orla-Jensen) Holland (Bacillus casei alpha v. Freudenreich and Thöni, Streptobacterium casei Orla-Jensen), a bacterium which is of importance for the cheese ripening process on account of its proteolytie activity. Many strains of this species show active break-down of casein when inoculated into milk containing calcium carbonate (Orla-Jensen 1919 (1)). No satisfactory explanation for the general occurrence of L. casei has so far been given.¹ In the present work a factor for the development of L. casei has been studied, namely the influence of the cell content of Str. lactis and Str. cremori.

EXPERIMENTAL

In the course of the study the following strains were used:

From the collection of Dr. S. Orla-Jensen, Copenhagen: Streptococcus cremoris No. 37, Str. lactis No. 7, Str. lactis No. 17, Str. lactis No. 22, Beta-coccus cremoris No. 7, Streptobacterium casei No. 7, Streptobacterium casei No. 11 and Thermobactermm helveticum No. 12.

¹ This organism should not be confused with Lactobacillus helveticus (Orla-Jensen) Bergey et al. {Bacillus casei epsilon v. Freudenreich and Thoni, Thermooacterium helveticum Orla-Jensen) which is of the greatest significance for the ripening of Swiss cheese, but, unlike L. casei, it is not generally found in all kinds of cheeses.