What is High Pressure Processing (HPP)?
Pascalization, bridgmanization, or high pressure processing (HPP), is a method of preserving and sterilizing food, in which a product is processed under very high pressure, leading to the inactivation of certain microorganisms and enzymes in the food. The technique was named after Blaise Pascal, a French scientist of the 17th century whose work included detailing the effects of pressure on fluids. During pascalization, more than 50,000 pounds per square inch (340 MPa) may be applied for around fifteen minutes, leading to the inactivation of yeast, mold, and bacteria.
Pascalization stops chemical activity caused by microorganisms that play a role in the deterioration of foods. The treatment occurs at low temperatures and does not include the use of food additives. From 1990, some juices, jellies, and jams have been preserved using pascalization in Japan. The technique is now used there to preserve fish and meats, salad dressing, rice cakes, and yogurts. An early use of pascalization in the United States was to treat guacamole. It did not change the guacamole’s taste, texture, or color, but the shelf life of the product increased to thirty days, from three days without the treatment. However, some treated foods still require cold storage because pascalization does not stop all enzyme activity caused by proteins, some of which affects shelf life.
How does it work?
Most processed foods today are heat treated to kill bacteria, which often diminishes product quality. High pressure processing provides an alternative means of killing bacteria that can cause spoilage or food-borne disease without a loss of sensory quality or nutrients.
In a typical HPP process, the product is packaged in a flexible container (usually a pouch or plastic bottle) and is loaded into a high pressure chamber filled with a pressure-transmitting (hydraulic) fluid. The hydraulic fluid (normally water) in the chamber is pressurized with a pump, and this pressure is transmitted through the package into the food itself. Pressure is applied for a specific time, usually 3 to 5 minutes. The processed product is then removed and stored/distributed in the conventional manner. Because the pressure is transmitted uniformly (in all directions simultaneously), food retains its shape, even at extreme pressures. And because no heat is needed, the sensory characteristics of the food are retained without compromising microbial safety.
The advantages of High Pressure Processing
- Minimal changes in the fresh characteristics of foods such as taste, appearance, texture, and nutrition by eliminating thermal degradation.
- Inactive pathogens such as Listeria, Salmonella, E. coli, Norovirus etc. to ensure the food safety.
- Extend product shelf life: expand the distribution, improve customer satisfaction, lower returns.
- Avoid or reduce the need for food preservatives by serving the clean label foods.
- Environmentally friendly: only needs water which is recycled and electricity.
- Suitable for both liquid and solid foods such as RET meals, meat, avocado, salsa, dipping, juice, salad, seafood etc.