The heat-mixing process (initial temperature of 65 or 70 C)
achieved only 1.2 to 2.9 log Salmonella reduction respectively in
20 min (final temperature 55 C). The reduction was none (65 C) or
very slow (0.65 log cfu at 70 C) after 10 min of the heat-mixing
process. It is believed that the distribution of salmonella in highfat
low-water activity product is grossly heterogeneous that
results in its decreased heat sensitivity over time (Shachar & Yaron,
2006.). A portion of the bacteria would be located in a relatively wet
environment, others in a dryer environment but still in a low-fat
area, or in a more fatty environment. Upon exposure to heat, the
least protected bacteria would die rapidly, followed more slowly by
the other bacterial groups. Furthermore, the difference in temperature
profile before and after 10 min of the heat-mixing process
may have affected the survival. Although, the heated
ingredient mixing of peanut butter flavored fondant ingredients
and room temperature storage together in this study achieved a 5-
log reduction of Salmonella after 5 weeks, there was a presence of
Salmonella in samples even after a year of storage. Therefore, the
need for good sanitation procedures exists to prevent contamination.
In practice, the level of Salmonella inoculum that may associate
in a potential contamination is much lower than the level used
(about log 7) in this study. This high level of inoculum is required to
see if 5 log reductions can be achieved. Therefore, future study with
low level of inoculum needs to be carried out to check the effect of
processing and storage in the survival of Salmonella.