23 C for 1 year. They suggested that, because of the
close link of streptococci and lactobacilli in fermentation,
both types of organisms were important in survival of
bacterial cultures.
L. acidophilus and B. lactis decreased rapidly in control
samples. The viable counts were 105 cfu g1 by the end of
the 90 day storage period. The decrease in the numbers of
L. acidophilus and B. lactis in samples supplemented with
inulin was less than those of the control samples and the
viable count at the end of 90 days storage period was
106 cfu g1. In all samples, the number of B. lactis was
higher than that of L. acidophilus. Hekmat and McMahon
(1992) found that the viability of L. acidophilus in a standard
ice-cream mix decreased by 2log cycles after storage
for 17 weeks at 29 C.
Since ice-cream is a whipped product, oxygen is incorporated
in large amounts. Bifidobacterium is strictly anaerobic;
therefore, oxygen toxicity may be a major factor of
cell death (Kailasapathy & Sultana, 2003). Kailasapathy
and Sultana (2003) reported that the viability of B. lactis
decreased by 1.8 and 2.4 log cycles, respectively, when present
in non-fermented types of ice-creams. Haynes and
Playne (2002) found that in a low fat ice-cream, B. lactis
BLC-1 survived better than did L. acidophilus LaftiTM L10
and L. paracasei subsp. paracasei LCS-1 over 52 weeks at
25 C.