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  • Cornell AgriTech
The Cornell High-Pressure Processing (HPP) Validation Center opened in 2017, the first facility of its kind nationwide.

Have you wondered why guacamole on supermarket shelves can stay fresh and green for so long? Or how cold-pressed juice can taste freshly squeezed, even after days or weeks in the refrigerator? It's all thanks to High Pressure Processing (HPP). Instead of using heat, HPP uses massive amounts of pressure transmitted through water to destroy microorganisms and pathogens that can lead to food spoilage. 

Ann Charles Vegdahl is an extension associate with the Cornell HPP Validation Center. The Cornell HPP Validation Center was the first commercial-scale validation facility installed within a Biohazard Level 2 Facility. 

Ann spoke with us about her work with the HPP Validation Center, the types of food products made with HPP technology and why the facility at Cornell AgriTech is so unique.

What is your background in food science and how did you become involved in High Pressure Processing?

I earned a Bachelor's degree in molecular and biological sciences at the University of Connecticut and a doctorate in microbiology at Rutgers University. After graduating, I worked for three years at the Cornell Food Venture Center as a process authority helping bring new food products to market. When the opportunity to work at the HPP Validation Center presented itself, I accepted. I currently manage the Cornell HPP Validation Center and the Cornell Microbial Food Extension Lab under professor Randy Worobo's supervision. 

What advantages does HPP offer over other forms of food processing?

HPP is a non-thermal (cold pasteurization) technology that inactivates many foodborne pathogens and spoilage microorganisms, extending shelf life. This process has minimal effect on taste, texture, appearance or nutritional values. HPP meets growing consumer demand for clean-label ingredients and product freshness, without the use of chemical additives or preservatives. It's environmentally friendly because it only requires electricity and water, which can be recycled. 

Cornell AgriTech is home to the only HPP validation center combined with a biosafety level 2 lab. What does that mean for the work the Cornell HPP Validation Center can do?

That status creates a unique opportunity to work with foodborne pathogens and a commercial-grade HPP machine. When we conduct validation studies, we innoculate the food sample with a known amount of pathogens, run the food in the HPP machine and enumerate the microbial population. This is critical for regulator compliance, as they need to see a greater than a 5-log (100,000-fold) reduction. We also collaborate with other research groups within the university, as well as governmental agencies and the private sector industry. 

What are some of the more rewarding aspects of your job?

The most rewarding part of my role here at Cornell is when I got to my local supermarkets and see food products that we validated. It puts a smile on my face because I know that I helped this company reach its goal. 

What are some common food products you regularly work with? 

HPP works best with fruit and vegetable juices, smoothies and purees. Ready-to-eat meals, such as sauces, salsas, soups, dips, pesto, hummus, meats and seafood, are all excellent candidates for HPP. The ideal product has a pH of 4.6 or below and a water activity level above or equal to 0.96. Products containing entrapped air, such as whole fruits and vegetables, leafy vegetables, baked goods, dried spices, and nuts are not good candidates for HPP. 

What kind of responsibilities fall under your role?

I work with a team of proficient technicians, who interact with manufacturers and perform most of the laboratory experiments. I review and analyze the data and generate the final reports. Depending on the scope of the project, I sometimes design the experiment. 

What else should people know about HPP?

HPP is a unique technology that ensures the safety and extends shelf life. However, it is expensive, which can be a limiting factor for small manufacturers. 

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