HPP: Power of Water Pressure in Food Preservation

Traditional food preservation technologies, like heat pasteurization, have significantly increased the safety of the food supply over the years. Unfortunately, many of these commonly used preservation techniques negatively impact the flavor, texture, nutrients, and color of food products. Additionally, consumers have become familiar with the not-so-fresh flavors of products with chemical preservatives. These concerns combined with the food production industry’s latest focus on keeping labels as clean as possible have made High Pressure Processing (HPP) a popular technology in the food production industry.

Having evolved from a novel food preservation concept to a go-to method called for by food manufacturers and their retail partners, many companies are finding themselves under pressure to learn more about how to best use the pressure of water. The following is a primer on what HPP is and can do, and the best practices companies can adhere to when making the transition to the HPP.

The 411 on HPP

Unlike heat pasteurization, which often negatively impacts food vitamins and nutrients when addressing bacteria, HPP’s cold pasteurization offers the opportunity to enhance food safety, while at the same time maintaining the fresh taste, bite, and color of the product in its natural state. HPP interrupts the cellular function of microorganisms by applying enormous pressure to foods for a period of just a few minutes. In most cases, this isostatic (equal from all sides) pressure is applied after the food is packaged, virtually eliminating any chance of recontamination.

Most HPP foods are technically non-sterile, i.e. not shelf-stable, but research studies completed on a wide range of food products and categories confirm that HPP technology effectively inactivates vegetative bacteria like Listeria monocytogenes, Salmonella, E. coli 0157:H7, and Campylobacter as well as yeasts, molds, and other fungi. It is a log-reduction food preservation technology which, in simplest terms, means that the higher the process pressure and longer the hold time, the greater the reduction of microorganisms—to a point. HPP is not effective on some enzymes and bacterial spores, including Clostridium botulinum. Producers need to tap into other techniques, such as blanching (for vegetables), and possibly adding a very small amount of natural antimicrobials or anti-clostridia ingredients to address those components not affected by HPP.

HPP provides additional value beyond its food safety benefits in the form of significantly increased shelf life. Because HPP inactivates most spoilage organisms, food processors frequently report dramatically increased product shelf life, often by more than twice the results without HPP.

Delivering a high-quality, cleaner-label product with prolonged shelf life can unlock all kinds of value. Some processors use HPP as an opportunity to increase their batch size and reduce the frequency of production runs. Because of the much longer product shelf life, a manufacturer on the East Coast can now tap markets in the Midwest and the West Coast. Others have seen HPP as an opportunity to provide new kinds of offerings or foods in different parts of the store. For example, avocados have traditionally been sold as a perishable item in the produce section and must be sold, donated, or thrown out within a matter of days. Avomex/Fresherized Foods was able to slice, pit, hermetically seal, and process avocado halves using HPP for a new product in the retail refrigerated sections. With HPP, the avocados last 30 days without turning brown or losing their optimal taste and quality—all done without the use of chemical preservatives.

Four Keys to Implementing HPP

While the benefits of switching from thermal pasteurization to HPP are often well worth the cost, changing processing methods is a major step that ought to be carefully considered before any definitive action is taken. The following four points are what food brands should keep in mind as they consider making the switch.