Ensuring Pecan Safety Through Conditioning

With these encouraging data in hand, the next step was to get some consumer feedback on kill step-validated, hot water-conditioned pecans. To that end, Dr. Adhikari and his team evaluated consumer acceptance and purchase intent of dehulled and roasted pecans that had been preconditioned in hot water according to the aforementioned protocol. Results were published in January 2019.

“We presented 112 consumers with roasted raw pecans as a control and roasted pecans pre-treated with hot water at three respective time-temperature combinations,” Dr. Adhikari says. “The volunteer panel included LSU faculty, staff, and students, roughly equal numbers of males and females. Consumer acceptance was higher for hot water-treated pecans, with higher ratings on color/appearance and aroma. No effect of hot water pretreatment was observed by consumers on other sensory properties, such as texture and flavor.”

Based on all of these results, Dr. Adhikari believes hot water conditioning holds greater promise than ever before for the commercial pecan industry. “Hot water conditioning has the potential to be regarded as a kill step to ensure the safety of pecans,” he emphasizes. “The treatment will also enhance the color and aroma of the pecan without affecting its texture and flavor. Since hot water conditioning is already in practice by most U.S. pecan shellers, no additional cost is required for setting up the system.”

During the Louisiana Pecan Growers fall field day in September 2018, Dr. Adhikari surveyed the producers and processors in attendance after he presented the results of his hot water conditioning research. “Some 80 percent of the respondents agreed that they will evaluate the microbial food safety risks associated with their pecan production and processing practices,” he reports. “About 75 percent of the growers said they would be willing to adopt this technology within the next two to three years.”

Dr. Adhikari says the hot water treatment process may hold promise for application to other nut species. “Hot water treatment has already been extensively used for tree nuts, especially almonds,” he relates. “Recent research indicates that pine nuts, black walnuts, and chestnuts could benefit from hot water treatment by reducing food safety risks and increasing shelf life. However, thermal processes validated for one nut type cannot be generalized to all tree nuts. The efficacy of hot water treatment may be affected by the shape, size, surface area, or other characteristics associated with each specific nut species. Therefore, validation of hot water treatment for each type of nut must be performed before commercial use.”