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Fcbruary 196 8
Charles G . P h e i l
The bactericidal and/or bacteriostatic effe cts at 30 and 55C of
a
glucose-fructose s yrup (25% alkali conversion, pH 4 .8, 68 %
solids) were
evaluated . The s yrup was inoculated with known concentrations
of the
foll owing microorganisms : Saccharamyces rouxii, xero l illic
fungi-M-2 ;
S . aureus, L . mesenteroides, E . coli, B. sub-tiTis, vege
tative cel is) ;
and Ps . fluorscens. After the im t al number of organisms was
de termined,
the seal ed tubes Tiere incubated at 30 and 55C . The number of
viable cell s
were determined at periodic intervals up to 10 days . The
results in the
following table indicate that the syrup s tored under the se
conditions
was bactericidal to all organisms e xcept B . subtilis (at 30C)
and M-2 .
The syrup was bacteriostatic to B . subtilis at 30C and M-2, in
that a
two slope curve was observed ; a fast initial rate (up to 3
days) foll owed
by a bacteriostatic effe ct (slight reduction in viable numbers
) .
Incubation Temperature
Ol-qanismest
Initial number
per ml
30C
D-vaTuel
(hrs)
55C
(hrs)l
S . rouxii 3 .3 x lOs 1 4 . 9 est . 13 . 0 2
M-2 1 . 3 x 1 0 ' ' 48 . 2 4 4 . 8
S . aureus 8 .4 x 107 est .3 9 . 1 est . 9 . 1
L . mesenteroides 6 . 6 x 7 0 ' ' est . 1 4 . 1 est . 1 4 .
9
F . coli 7 .0 x 107 e st . 9 . 2 est . 9 . 2
subtiles 1 .6 x 10518 .3 (to 1 day)
3 5 . 8. - (1-10 days)15 .P s . fluorscens 3 .4,x 106 20 . 4 est
. 1 1 . 0
1 D value is defined as time to reduce,viable population one log
cycle or
90% D _ time (hrs)logNo - logNt
2 Since the viable counts were les s than one/ml at time, t,
these values are
rough approximations and the se values may be much lowe r .
The e ffects of various concentrations of G-F syrups (55-65% sol
ids) at
other storage temperatures (35-50C) will be evaluated as s oon
as the
alkali-converted G-F syrup is available .
The e ffect of bagasse xyl ose on glucose-is omerase production
by
actinoraycete (S-2) and a fungi (M-4) was evaluated . The e
nzymatic activity
with S-2 was approximately equal to the control (RJR 2453-2)
using 1 & 2%
bagasse xylose (
