A multistate outbreak of Salmonella enterica serovar Typhimurium recently occurred in the USA, which
was traced back to various food products made with contaminated peanut butter. This study was conducted
to investigate the efficacy of radio-frequency (RF) heating to inactivate S. Typhimurium and
Escherichia coli O157:H7 in peanut butter cracker sandwiches using creamy and chunky commercial
peanut butter and to determine the effect on quality by measuring color changes and sensory evaluation.
Samples were treated for a maximum time of 90 s in a 27.12 MHz RF heating system. Samples were
prepared in the form of peanut butter cracker sandwiches and placed in the middle of two parallel-plate
electrodes. After 90 s of RF treatment, the log reductions of S. Typhimurium and E. coli O157:H7 were 4.29
and 4.39 log CFU/g, respectively, in creamy peanut butter. RF treatment of chunky peanut butter for 90 s
also significantly (P < 0.05) reduced levels of S. Typhimurium and E. coli O157:H7 by 4.55 log CFU/g and
5.32 log CFU/g. Color values and sensory characteristics of the RF treated peanut butter and crackers were
not significantly (P > 0.05) different from the control. These results suggest that RF heating can be
applied to control pathogens in peanut butter products without affecting quality.