Infrared pasteurization of raw almonds

Due to outbreaks of salmonellosis associated with whole raw almonds, an infrared (IR) pasteurization process was investigated for its efficacy in improving the safety of raw almonds. After almonds were heated to 100, 110 and 120 °C with IR, they were cooled at ambient temperature to a holding temperature of 70, 80 or 90 °C before being transferred to a custom-designed holding device for different time periods up to 60 min. We observed that holding almonds at 90 °C for 10–15 min reduced the Pediococcus population size by more than 5-log and holding at 80 °C for longer than 22 min provided more than 4-log reduction, thus satisfying the targeted 4-log reduction required in the almond industry. The L∗a∗b∗ color values of whole almonds were not affected significantly (P > 0.05) by the IR process whereas the a∗ and b∗ color values of ground almonds changed significantly (P < 0.05). The sensory panel did not detect any significant difference (P > 0.01) in appearance, texture, flavor and overall quality of pasteurized almonds compared with untreated samples.