Q&A from the Validation of Thermal Process Applied to Low-Water Activity Foods Webinar
Following the recent webinar titled "Validation of Thermal Processes Applied to Low-Water Activity Foods" experts Shirin Abd and Dr. Wilfredo Ocasio answered some frequently asked questions.
Q: I have a large number of similar low-moisture products. Do I have to conduct validation studies for all of them?
A: No, not necessarily. If you have a large number of products, Eurofins would be able to assist you by conducting a product/process assessment to review the intrinsic and extrinsic properties of the products and categorize them and if possible, select the “worst-case scenario” product from each category for use in the on-site validation study.
Q: Is a 5-log reduction always needed for a successful validation?
A: If the performance criteria is not defined for your specific product and process, a 5-log reduction is commonly selected. However, a lower target log reduction may be considered if you have done a risk assessment for your product and process and you have enough data to justify a lower log reduction. For example, the Almond Board of California collected extensive data over years and evaluated the risk associated with their product, and they were able to justify a 4-log reduction as the performance criteria for their process validation studies.
Q: Is the on-site microbiological validation study required by the FDA?
A: Not necessarily. If you have a clear understanding of the resistance of the target pathogen in your particular product and process, you may be able to collect temperature data and then correlate that data to the lethality of the target pathogen. However, in most situations, the product’s moisture level is significantly changing as it goes through the production process. The relative humidity of the chamber may change and other variables that are difficult to predict may change, hence the necessity of the surrogate microbial validation. It is not an absolute requirement, but the necessity of conducting an on-site microbial validation study would have to be looked at on a case-by-case basis.
Q: Can I use information available in the scientific literature instead of conducting an on-site microbiological validation study?
A: Connected a bit to the previous answer, if there is information in the scientific literature that can be applied to your product and process specifically, you may be able to use that information. Again, the preventative control rule opens the door to conducting a validation in different ways. The validation could be based on available scientific literature, via information from trade associations, industry standards, etc., as long as the source data is scientifically valid and specific to your product and process. Scientific literature is unlikely to be available for novel products or processes.
Q: Water activity changes throughout many of these processes, what water activity do you use to evaluate your surrogate?
A: Ideally, you want to evaluate the surrogate in different matrices. For example, if the water activity is changing in the process then you should evaluate the heat-resistance of the surrogate in the product at the beginning, middle, and end of the process, but this is not always possible. Therefore, the “worst case scenario” product, which is the finished product at presumably the lowest water activity, may be evaluated as the heat-resistance of the surrogate in this product matrix would be expected to be high or “worst-case”. However, determining which water activity to evaluate for the validation study needs to be done on a case-by-case basis. In some cases, evaluating only the finished product might lead to excessively severe thermal requirements and the intermediate product may be used for the surrogate evaluation instead. Again, each case needs to be considered, studied, and evaluated carefully to select an appropriate product matrix and surrogate for the evaluation.
Q: Is Salmonella always the target pathogen?
A: It is the most common pathogenic organism for low water activity products, but it's not the only target organism. Pathogenic E. coli, Listeria monocytogenes, and Cronobacter sakazakii have been the cause of foodborne outbreaks in low-moisture foods as well. For the selection of the organism, we recommend reviewing your food safety plan, considering also the risk associated with your product or similar products (and potentially product ingredients) based on previous foodborne outbreaks, associated illnesses, and recalls.
Q: What do you do if the surrogate evaluation shows that the target pathogen is more resistant than the surrogate organism?
A: It depends on the magnitude of the difference. In most situations, you would have to search for another surrogate organism that is a better candidate for use as a surrogate for the target pathogen. Usually, that is a significant effort, but other surrogate organisms do exist. If the pathogen is just slightly more resistant compared to the surrogate and you can quantify the magnitude of the difference, you may be able to adjust the inoculation level up higher to compensate for the lower resistance of the surrogate.
Learn more about our Validation of Thermal Process capabilities with this webinar, or contact us to learn more!
