August 2016

Research and Development

Optimized High Pressure Processing Improves Food Safety


Januana Teixeria, post-doctoral fellow on this project.

New research is underway to determine the best combination of temperature and high pressure processing (HPP) to fully destroy Listeria monocytogenes – commonly referred to as Listeria – in ready-to-eat (RTE) meat products.

Listeria causes severe foodborne illness in humans, primarily from exposure to contaminated dairy products and prepared meat products.1

Presently, processors use HPP as a means to destroy Listeria from meat products during processing and prior to refrigeration. However, HPP does not always fully destroy Listeria. This allows the bacteria to grow during subsequent refrigeration.

Current data on RTE meats indicates that HPP processing at cold or ambient temperatures does not consistently result in a 5-log reduction of Listeria. Log reduction is used to show the relative number of live microbes eliminated from a food product by processing. A 5-log reduction of microbes means that less than one in 100,000 cells survive and indicates that the process destroys microbes to a safe level.

Dr. Lynn McMullen, from the University of Alberta, is currently researching combinations of heat and pressure to achieve greater than 5-log results using HPP to destroy Listeria. “The goal of this research is to find the right temperature and HPP blend to ensure a sufficient reduction of Listeria so the RTE meats are guaranteed free of Listeria and remain so during storage.”

With support from the Alberta Livestock and Meat Agency (ALMA), Dr. McMullen will also study the impact of natural antimicrobials on the lethality of HPP in meat products, and whether physiological or genetic mechanisms are responsible for the increased tolerance of Listeria to HPP treatments. The inclusion of natural antimicrobials may increase the efficiency of HPP treatments, while decreasing the risks to consumers.

Dr. Susan Novak, Executive Director of Strategic Initiatives with ALMA, sees the benefit in this type of research. “Development of a process to eliminate Listeria helps demonstrate Alberta and Canada’s commitment to providing safe meat products. This is key to a healthy and profitable livestock and meat industry, as it goes further to ensure food safety.”

For more information on this project, email Dr. Lynn McMullen at

1 Bortolussi, R, “Listeriosis: A Primer,” CANADIAN MEDICAL ASSOCIATION JOURNAL, Vol. 179, No. 8, pp. 795-7 (Oct. 7, 2008), online at: