Internally-pH-controlled, phosphate containing and non-phosphate
containing Italian bulk starter media were compared to
reconstituted nonfat dry milk and commercial bulk starter media
for their ability to support the growth and activities of
commercially frozen thermophilic lactic acid cultures. Cultures
grown in internally-pH-controlled media demonstrated superior
acid-production capability. The cheese made from cultures grown
in internally-pH-controlled media was comparable to that made
from the culture grown in commercial medium. However, the
internally-pH-controlled media were not bacteriophage inhibitory,
nor were the reconstituted nonfat dry milk or two of the three
commercial bulk starter media. Hence, cheese whey and nonfat milk
based, low solids, bacteriophage inhibitory bulk starter media
were formulated for the cultivation of mixed cultures of
Streptococcus thermophilus and Lactobacillus bulgaricus. The new
media supported the growth of lactobacilli better than the
commercial media. Even at low solids levels, the buffering
capacities of the new media were comparable to commercial media.
Late addition of magnesium hydroxide as a neutralizing agent to
commercial as well as experimental bulk starter media resulted in
increased growth and improved activities of rod-coccus cultures.
The cultures also retained their activities longer under
refrigerated storage. Late addition of magnesium hydroxide did
not encourage the proliferation of bacteriophages in the growth
media. / Graduation date: 1987
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/38252 |
| Date | 01 August 1986 |
| Creators | Rajagopal, S. N. |
| Contributors | Sandine, William E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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