Environmental swabs in this study highlighted that the surfaces
of the transfer conveyors,
especially the surfaces of out-feed transfer
belt and swings of out-feed transfer belt of chiller and freezer
(Table 1) were the main contamination sites and thus they could
be the major source of product contamination since they directly
contacted with the products, Therefore, it was deemed to be
worthwhile to study and establish a model of the cleaning and sanitizing
process of those conveyors to manage the appropriate
method and conditions, of the process.
In addition, the model could
be use to predict the probability of viable microorganisms still
residing in the zone when the cleaning conditions were adjusted.
Steps 3–5 of the cleaning and sanitizing process were selected
for this analysis and model development since these steps likely
represent where most of the reduction in viable bacteria on the
surfaces occurs. The risk factors involved in these steps can also
easily be inadvertently changed by the factory, but may be important
or critical and thus some form of predictive understanding of
their importance and overall affects would be of a great advantage.
Therefore, the risk factors for each of the three selected steps of
cleaning and sanitizing analyzed were (i) the contact time of Quorum
Pink II HF detergent, (ii) the concentration of acetic acid and
(iii) the contact time of chlorine, for steps 3–5, respectively. It
should be pointed out that the contact time of detergent and chlorine
were selected excluding their concentrations, despite the clear
importance of this, simply because the concentration of these two
reagents were usually fixed by the factory and somewhat easily
and reliably controlled, whereas the contact time was frequently
changed, knowingly or not, by the factory staff. This might be