For the purposes of public health, corporate liability and reputation, neglecting food safety practices is not an option. But based on physical parameters alone, it often is unclear whether a food product will support growth of a pathogenic microorganism; how long a pathogen may take to produce a significant level of toxin or reach a population level to cause illness; or what actual processes are necessary to eliminate a pathogen hazard. However, well-designed challenge studies, thermal death time (TDT) studies, and process validations provide valuable scientific information that can be applied to ensure public safety.

“To minimize public health risk and prevent regulatory violations, food safety studies must be done on foods in which risks are present,” adds Wilfredo Ocasio, Ph.D., vice president of Microbiology and Process Research at The National Food Laboratory - the NFL (Dublin, Calif.), an FDA- and USDA-recognized processing authority.

Challenge studies help food processors understand which contaminating pathogenic microorganisms are likely to either survive or grow in their products.

“When food processors venture outside safe harbor parameters, say for quality or yield, it's necessary to validate the process with a challenge study,” said Scott Stillwell, director of Food Safety and Regulatory Compliance for Tyson Foods (Springdale, Ark.), a world leader in producing and marketing chicken, beef, and pork. “Under Hazard Analysis Critical Control Point (HACCP) rules, companies must establish the safety of their products themselves, but many may not have the expertise to comfortably change from safe harbor standards to HACCP rules. That's where having an objective third party expert really helps. Bottom line, companies need a safe product that's not only defensible with regulators, but also defensible in court if necessary.”

Once a pathogen is found to have the ability to reproduce in a food product, TDT studies can help determine formulation-specific heat resistance of the pathogen in that product. This helps identify the proper cook time and temperature needed to kill the pathogen, and allows existing processes to be fine-tuned in order to optimize product quality and reduce cost.

After challenge and TDT studies have been completed, process validation is needed to verify that the processes work as planned under real manufacturing conditions. Typically, this may include conducting heat penetration, heat distribution, and inoculated pack testing to support process filings with regulatory agencies.

“Process validation is a critical final step in assuring food safety, in essence, like putting theory into practice,” says the NFL's Ocasio. “And if there ever is a safety issue that needs to be looked into, regulators look not just at the sample but also investigate the processing facility, its records, and documentation used to assure the efficacy of the process. These documents include any scientific basis on which the process was designed. Process validation ensures and proves that the food safety process does, in fact, work as intended.”

Though Tyson Foods has the resources to internally conduct several types of studies, the company still seeks independent validation, protocol development, and surrogate pathogen modeling. “For these types of studies, third party expertise brings an added level of safety to consumers as well as rigor and credibility to process designs,” adds Stillwell.

For more information

Dr. Paul Gerhardt at 925-551-4285
GerhardtP@TheNFL.com
www.TheNFL.com National Food Laboratory Write in 402

Borrowed Parameters

“Without adequate TDT expertise, a food processor may fail to recognize attenuating or exacerbating factors—such as fat, salt, water, pH level or other conditions—that contribute to pathogen death or survival. That's why using results from other studies in your process can be dangerous. If a product isn't very similar to the one you're producing, the results won't be applicable.”

— Scott Stillwell, Tyson Foods