ficient to adequately control the hazard risk, additional controls
must be undertaken. To illustrate this and using the foot plate
source as described in Table 1, the frequent use of chlorine disinfectant may not be a sufficient control, and it may be necessary either to lift the equipment, decontaminate the area under
the foot plate and then reseal the foot plate to the floor or purchase new foot plates or equipment supports of a more hygienic design.
Subsequent controls should also be considered when assessing the risk of a cross-contamination event. In the theoretical
example in Table 2, operatives must insert a guillotine or spray
cap into the powder line to prevent clean-in-place (CIP) fluids
entering sensitive areas during the dryer CIP program, for example, the bag house where powder is removed from the airflow exiting the dryer. Any microbial contamination entering
the dryer, particularly during the removal of the guillotines,
would then be subjected to the dryer start-up procedure, which
could include the circulation of heated air for several hours
(e.g., 205 °C/400 °F for 2 hours).
In the second dryer intervention example in Table 2, the re-
moval, cleaning and insertion of the milk spray nozzles could
occur a number of times between CIP events of the dryer, such
that any microorganisms entering the dryer during these poten-
tial cross-contamination events would not be subjected to a
process control step. In this example, it is possible to do a risk
assessment on the cross-contamination event (particularly if the
cross-contamination event results in a high-risk score) or indi-
vidual vectors related to the event to determine which vectors
are most important to control. In this case, entry of air has
been identified as a vector and the risk assessment for the air in-
dicates that other vectors associated with the cross-contamina-
tion event may be more important.
