Decontaminate nuts
Researchers at the Fraunhofer Institute for Environment, Safety and Energy Technology (UMSICHT; Oberhausen, Germany; www.umsicht.fraunhofer.de) have developed a new process that uses compressed carbon dioxide to decontaminate almonds, nuts and other dry foodstuffs. In a joint project with the University of Alberta (Canada) and supported by the German Federal Ministry of Education and Research (BMBF; Bonn), UMSICHT researcher Karen Fuchs and her team investigated technologies that could serve to decontaminate almonds.
“It is common knowledge that pressurized CO2 can kill pathogenic bacteria in liquids, such as orange juice. Our research has shown that under certain conditions this also works with dry food,” says Fuchs. In one process step, almonds are decontaminated and impregnated with antimicrobial oils using compressed CO2 in a high-pressure autoclave. The oil extract coats the almond, making it difficult for germs to re-contaminate the fruit. The advantage of this process is that almonds retain their characteristic flavor and quality. Fuchs and her team carried out tests with Staphylococcus carnosus, a surrogate organism known for an even more resistant reaction than Salmonella, proving that the process in the autoclave does not adversely affect the shelf life, rancidity or lipid composition of almonds. This process also lends itself to other foods.