Quantifying the Performance of Pediococcus sp. (NRRL B-2354: Enterococcus faecium) as a Nonpathogenic Surrogate for Salmonella Enteritidis PT30 during Moist-Air Convection Heating of Almonds

Pediococcus sp. NRRL B-2354 was investigated as a potential nonpathogenic surrogate for Salmonella enterica serovar Enteritidis phage type 30 (SE PT30) on the surface of almonds subjected to moist-air heating. Both microorganisms were subjected to various time, temperature, and humidity regimens on almonds processed in a computer-controlled, laboratory-scale, moist-air convection oven. Overall, the mean log reductions for Pediococcus sp. were 0.6 log and 1.4 log lower than those for SE PT30 (P < 0.05) at predicted reductions of 3 and 5 log, respectively. Also, the D(ref)-values for Pediococcus sp., calculated using a modified inactivation model (accounting for moisture) for SE PT30 on the surface of almonds subjected to moist-air heating (30 to 90% moisture by volume) were similar to 30% larger than those for SE PT30. Based on these findings, Pediococcus sp. NRRL B-2354 can be used as a conservative surrogate for SE PT30 during moist-air heating, and this organism is also likely to be an acceptable surrogate for steam heating.