Three commercial sausage starter cultures were grown in
an internal-pH-controlled medium (PHASE 4) and in a soluble
phosphate-buffered medium. The cultures were tested by
comparing viable counts before and after freezing at -40 C
or freeze-drying and subsequent storage for 3 months in the
frozen or dried state. Strains varied...
Mutants of Streptococcus lactis 7962 with various combinations of plasmid molecular masses were screened for nisin production. Nisin was produced by both wild type and mutants that contained a 17.5 Md plasmid, which was usually obscured by the chromosomal fragments. No nisin was produced by plasmid-free mutants. Sucrose fermentation and...
Fast acid-producing streptomycin-resistant mutants for several
strains of lactic streptococci currently used in commercial Cheddar
cheese manufacture were isolated. Their isolation involved use of a
recently developed differential plating medium that allows identification
of fast acid-producing colonies. Both parents and mutants were characterized
with regard to growth, acid production, proteolytic...
The fecal flora of healthy bottle or breast-fed infants was
examined for the presence of Bifidobacterium. Identification was
based on the presence of fructose-6-phosphate phosphoketolase,
which is found only in these bacteria. No bifidobacteria were
recovered from bottle-fed infants. However, bifidobacteria were
readily isolated from 15 day to 3 month...
A method for rapid isolation of plasmid DNA from group N
streptococci was developed. Chief advantages of the method were
simplicity, the utilization of microliter quantities of reagents,
and the obtainment of preparations highly enriched for covalently
closed circular plasmid DNA. The method was also applied to over
15 Leuconostoc...
Lactobacilli are microorganisms with many applications in the
fermented food and dairy industries. In addition to the actual
fermentation of food products, lactobacilli are involved in the
metabolic breakdown of lactose in dairy products, enabling a large
population of lactose-intolerant humans to ingest milk. Lactobacilli
are also used as health...
A study of malolactic bacteria of the Leuconostoc
genus, especially L. oenos, and their bacteriophages was
conducted. A search for the presence of infectious
bacteriophages in grapes, musts, and juices employed in
malo-lactic fermentation (MLF) was conducted; no
evidence, either physical or biological, was found for
the existence of these...