Bacillus cereus excretes large amounts of penicillinase
into growth media during incubation, hence the
widely-used penicillin selection technique for isolating
biochemical mutants of bacteria is not applicable to this
species. Genetic transfer in B. cereus has not been
reported; this is partly due to the lack of an effective
isolation...
The dairy industry relies primarily on consistent acid production
by the lactic streptococci for the manufacture of certain cheeses
and fermented dairy products. Variation in these cultures due to
genetic exchange has not been thoroughly investigated. This study
was undertaken to determine if genetic homology exists within the lactic
group,...
The public health and economic significance of rapid acid production
by lactic streptococci in controlled dairy fermentations is well
known. However, the fast acid-producing characteristic of these organisms
is not stable, and cultures of fast organisms have been shown
to contain slow cells. These studies were carried out to characterize...
To determine whether some bacteria are more susceptible
than others to quaternary ammonium compounds, the following bacteria
were grown on agar slants containing various concentrations of
alkyl dimethyl ethyl benzyl ammonium chloride (ADEBAC), and alkyl
dimethyl benzyl ammonium chloride (ADBAC): Aerobacter aerogenes
12658, Alcaligenes metalcaligenes, Brevibacterium linens, Chromobacterium
lividum, Escherichia...
Comparisons were made of the abilities of Streptococcus lactis,
Streptococcus cremoris and Streptococcus diacetilactis bacteriophages
to endure various laboratory isolation and storage treatments.
Neutralization of Cottage cheese whey containing phages offered no
survival advantage over unneutralized samples, refrigeration of
neutral and acid whey samples increased the survival of only the...
This study involved an investigation of lactic streptococci which
had irreversibly lost ability to produce the high levels of acid in milk
necessary during the manufacture of certain fermented dairy products.
The slow acid producing mutants studied were obtained from
a normal acid producing strain by natural selection following induction...
This study was carried out to compare the effects of a quaternary
ammonium compound (QAC) upon strains of Pseudomonas aeruginosa
which were either sensitive or resistant to the germicide. The cationic
QAC used was alkyldimethylbenzylammonium chloride. The resistant
types were isolated from the sensitive population by selection
of mutants which...
This study was undertaken to determine the role Leuconostoc
citrovorum may play in carbon dioxide production in milk. The
ability of L. citrovorum strains to produce gas was studied by two
methods. A qualitative method used visual measurement of gas where
an agar plug was forced up the neck of...