Ready for a Process Validation?

Sherman L. Mah
Senior Manager Technical Services
Almond Board of CA Approved Process Authority
Certified Laboratories of California

Process validation requests, driven by customer requirements for compliance with the Food Safety Modernization Act, have been on the rise.  Whether the process is non-thermal (irradiation, high-pressure processing, etc.) or thermal (steam, roasting, retorting, etc.), there are basic steps to consider when preparing for a validation on both existing or new equipment that can help increase the success of this process.

Process Parameters

Determining the proper process parameters in which to execute the validation in order to successfully achieve the desired log reduction while still maintaining the quality attributes of the product is key.  Depending on the process, parameters include but are not limited to: time of the process; temperature of the process; temperature of input material; percent moisture/water activity; pH of input material; treatment dosage; treatment pressure; wavelength and product throughput. 

If process parameters have not been established, conducting pre-validation trials using suitable microbial surrogates should be considered to evaluate if the proposed process parameters will achieve the desired log reduction or if adjustments to the parameters are necessary. In addition, it’s at this stage product quality can be reviewed to determine if over processing or degradation of the product is occurring and whether adjustments to the parameters are required.

Product Matrix

For manufacturers that process multiple matrices, determining which product to validate first will more than likely be dictated by their client’s request and priorities. If customer requests are not driving the validation, the first product matrix that should be considered is the highest-volume product processed.

Surrogate/Pathogen Selection

Identification of the target pathogen(s) and/or it’s surrogate(s) to use in the validation trial is crucial.  Depending on the product matrix this could be one organism (Enterococcus faecium as a surrogate for Salmonella) or a cocktail of organisms that could include but is not limited to E. coli O157:H7, Listeria monocytogenes, Salmonella, and possibly Clostridium botulinum. The proper surrogate selection is critical to a defensible process validation.  A process authority or laboratory can assist in this determination if needed.

Equipment and Material Readiness

Prior to executing the validation, a checklist review should be conducted to aid the processor in understanding the requirements of the validation process. Depending on the equipment, this checklist can include current calibrations records for resistance temperature detectors, thermocouples, dosimeters, pressure gauges, chart recorders and other recording devices. Calibrations should be conducted by an accredited third-party service provider.

Material readiness is another important factor to consider and should be agreed upon prior to the validation. In general, to provide the processor with maximum flexibility in production, the validation should be conducted using the worst-case scenario material conditions. For example, when processing material using an oven, the temperature of the input material should be at the lowest temperature the material would conceivably be processed. That temperature will then become the minimum critical control parameter for input temperature. This provides the processor flexibility to manufacture product at temperatures above the CCP with no concerns about any adjustments necessary to bring the input material temperature down.

Moisture control of the input material is also critical factor depending on the type of process. Minimum and maximum percentage moisture should be considered when determining the level at which to run the validation.

Addressing Post-Process Contamination Concerns

Air quality in the processing area should be addressed with air filtration units or systems preferably with filters with a Minimum Efficiency Reporting Value 13 but no lower than MERV 8.

Physical separation by a wall between the raw processing area and the finished product is preferable, but a robust pathogen environmental monitoring program in place to monitor the facility for harborage of pathogenic organisms is acceptable.

Validation Logistics

Once the above steps have been completed the following validation logistics should be executed:

  • Scheduling internally with plant operations or externally with a tolling facility/sterilizer
  • Scheduling of a process authority (if onsite management is required)
  • Coordination of samples to be inoculated and surrogate preparation for the validation

Certified Laboratories is a private, independent laboratory comprised of four laboratories located in New York, Illinois, southern California and northern California.

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