Ideally, validation of targeted process control points can be simulated in a laboratory setting so appropriate Salmonella strains could be used for the evaluation.
Petfood
processors have become increasingly aware of the need to control Salmonella during production due to the
risk of associated pet and human illness. Processors know how problematic
this pathogen can be but may not fully understand the scientific dynamics
surrounding effective elimination and potential for recontamination during
processing based on heat resistance and persistence in low-moisture products
such as petfood.
Control
of Salmonella for petfood processors
requires a lethality, or “kill,” step as a critical point(s) during processing
to consistently support the production of Salmonella-free
products. Like other low-moisture food products, petfoods and treats require
special consideration in the development, validation and implementation of an
effective kill step based on the unique ability of Salmonella to resist thermal processing.
Moreover,
Salmonella can persist indefinitely
in a dehydrated state such that it remains viable and available for
recontamination of thermally processed, low-moisture food products and, thus, can
represent a food safety risk. Validation of processing steps used to reduce and
control Salmonella is necessary to
scientifically prove and ultimately demonstrate that a process is effective.
Collectively,
validation includes:
Salmonella can persist indefinitely in a dehydrated state such that it remains viable and available for recontamination.- Reviewing
scientific data for related products and processes;
- Determining
a proper log reduction for the specific process based on the expected, incoming
levels;
- Determining
defined critical limits to achieve the targeted reduction; and
- Confirming
that the equipment and process can consistently deliver the required parameters
to meet these limits.
Like other low-moisture food products, petfoods and treats require special consideration in developing and validating an effective kill step based on the unique ability of Salmonella to resist thermal processing.
Verification
activities and supportive records that demonstrate the process is consistently performing
according to the established parameters are also key to ensuring the validated
process has been properly implemented and maintained. This may include
equipment calibration and performance records as well as product performance
data possibly comprised of both chemical and microbiological data of raw
materials as well as in-process and finished products.
Validation
studies must also be designed to encompass the entire process being used to
prevent, reduce and control recontamination of the finished product. Further, use
of raw materials in the validation should represent those routinely used to
best assess process performance and therefore adequately validate actual
conditions.
Effectiveness
of a process should be determined considering the worst case scenario, using a Salmonella serotype with the greatest
level of resistance and handling conditions that would be representative of
those likely to occur during normal handling and distribution. Validation
conditions must be carefully developed, in particular for low-moisture food
products.
Based
on previous studies, it would be expected that thermal inactivation of Salmonella in low-moisture activity
matrices would not follow a linear pattern. It is crucial to identify process
authorities with knowledge and experience in conducting process validation
studies for similar matrices.
Effectiveness of a process should be determined considering the worst case scenario.Ideally,
validation of targeted process control points could be simulated in a
laboratory setting so appropriate Salmonella
strains could be used for the evaluation. Unique processes or those not
adequately simulated may need to be validated using a surrogate microorganism
that would be expected to react similarly to Salmonella. Such a microorganism could be applied to test products
and subjected to the process in the facility without representing a food safety
risk.
It
is possible that a combination of laboratory data based on process simulation,
combined with in-process data generated using surrogate organisms as well as
process verification records (e.g., time/temperature and pressure) may be
required to adequately establish critical control points (CCPs) and associated
parameters. Ultimately, validated CCPs established for the entire process would
demonstrate control of Salmonella
well beyond the minimum expectation that complete inactivation occurs within a
normal process.