Non-thermal techniques to protect food in supply chain

Combining pulsed electric and magnetic fields could address the loss of food quality due to freezing and thawing in storage and transportation.

During the freezing process, water crystallization can result in damage to tissue structures resulting in harm to foods.

Dr Soojin Jun of the University of Hawai‘i at Mānoa’s College of Tropical Agriculture and Human Resources (CTAHR) received a grant to study a way to preserve food for storage and shipping.  

Jun, an associate professor in CTAHR's Department of Human Nutrition, Food and Animal Sciences (HNFAS), will look at the loss of quality in food due to freezing and thawing during storage and transportation, which leads to waste and economic consequences.

3 year project

Jun and co-principal investigator Dr Peter Berkelman, an associate professor in the UH Mānoa School of Engineering, received a three-year, $500,000 grant through the USDA’s National Institute of Food and Agriculture.

“As long as the developed freezing technology is applied, the implemented supercooling stage of food materials, i.e., meat, fruits, fish, etc., can be longer, we anticipate,” Jun said.

“We plan to investigate the max extension of the supercooling stage and its stability as well.”

The project aims to preserve food freshness by controlling the supercooling and ice crystallization of water using combined pulsed electric and magnetic fields.

Non-thermal techniques

Pulsed Electric Field (PEF) is a non-thermal method of food preservation that uses short pulses of electricity for microbial inactivation.

Pulsed Magnetic Field (PMF) sterilization is a technology for the nonthermal sterilization of food.

Both non-thermal technologies are believed to have less effect on food qualities than traditional thermal methods.  

Supercooling refers to water temperature dropping below the freezing point, but there is no transition to ice.

The grant includes work on a prototype freezer equipped with (PEF) and oscillating magnetic field generators, designed in the HNFAS lab.

The technology has the potential to ensure food quality and freshness during storage and benefit Hawai‘i and the Pacific Basin by ensuring food security and sustainability, said the researchers.