January 28, 2016–Global Food Forums, Inc. — The following is an excerpt from the “2015 Clean Label Report,” sponsored by Loders Croklaan, RiceBran Technologies and SunOpta.
PROCESSING PANEL, Speaker 2: Kathiravan Krishnamurthy, Ph.D., “High-pressure Processing: Opportunities and Challenges”
High-pressure processing is an old technology that has become economically feasible through advances in engineering. Indeed, it is estimated that the cost of this processing technology has been reduced thousands of times over the last 100 years.
There are a number advantages to foods offered by the technology, noted Kathiravan Krishnamurthy, Ph.D., Assistant Professor of Food Science and Nutrition, Illinois Institute of Technology, as the second speaker on the clean label processing panel.
These benefits include:
• Extended shelflife and improved food safety
• Pressure inactivates yeast, molds, bacterial cells and most viruses
• Minimal change in food flavor, color, texture, nutritional value, providing fresh-like characteristics
• Improved food quality
• Fewer/no additives, which helps answer demands for clean labels
• Can alter products high in protein/starch and produce novel food products
In high-pressure processing, the pressure is transmitted uniformly throughout the product. The product is not crushed, yet vegetative cells of both spoilage and pathogenic microorganisms are inactivated. It will also inactivate viruses and denature some enzymes. Because high-pressure processing will not destroy spores, high-acid or acidified products may be more safely processed. They must also be refrigerated to protect quality.
In addition, most products that are now being processed using this technology are high-value items, such as guacamole, oysters and ready-to-eat (RTE) meats. Oysters have been a real success story. High-pressure processing has been shown to inactivate viruses, extend shelflife, increase the yield of meat and minimize the labor involved in shucking.
One challenge with RTE meats has been the potential for Listeria monocytogenes contamination following processing. High-pressure processing of packaged RTE meats eliminates this concern and extends shelflife.
Applying this technology to juices and other agricultural commodities has been shown to enhance shelflife, provide a fresh-tasting product and enhance product safety with minimal adverse effects on nutritional content. However, any processor wishing to adopt the technology as a means for ensuring food safety has another challenge. They must validate that the process will deliver a minimum of a 5-log reduction (99.999%) to the target pathogen or a non-pathogenic surrogate which has been shown to have similar resistance as the target organism.
There are a number of potential opportunities for high-pressure processing. These include extended shelflife yogurts, fresh fruit and yogurt products; cheeses that have the flavor of raw milk cheeses or those with improved texture; products in which post-packaging microbial contamination may be removed, such the RTE meat example cited earlier; and enhancing functional properties of different products and ingredients, such as those with bioactive properties.
High-pressure processing is one of the few novel, non-thermal processes that has become commercially viable. Combining high-pressure processing and heat (pressure-assisted thermal sterilization) can be used for producing shelf-stable foods by inactivating spores. Processors wishing to adopt high-pressure processing need to do their homework beforehand and closely examine the pros and cons of the technology, including equipment costs.
Kathiravan Krishnamurthy, Ph.D., Assistant Professor of Food Science and Nutrition, Illinois Institute of Technology, firstname.lastname@example.org, www.iit.edu/ifsh