Application of Far Infrared Radiation and Ethanol Vapor as Alternative Treatment Methods for Reduction of Salmonella enterica Tennessee in Dried, Ground Spices


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Virginia Tech


The consumption of spiced food is steadily increasing, subsequently leading to increased incidence of spice-related food illnesses. Many outbreaks can be traced to human pathogens that can survive in low moisture content of spices, prompting development of additional inactivation treatments that reduce bacterial pathogens while maintaining spice quality. Spices are currently treated by fumigation with ethylene oxide, pasteurization with ionizing radiation, or steam treatment. However, these treatments exhibit flaws pertaining to consumer preference, regulatory issues, and quality degradation. In this study, two novel treatments were evaluated for reduction of Salmonella enterica Tennessee: far infrared radiation (FIR), a short time â " high temperature treatment, and pasteurization with ethanol vapor (EV). Both treatments were effective in reducing levels of Salmonella Tennessee between 3-5 logs. FIR treatment showed increased efficacy at longer treatment times with a maximum reduction of 5 log CFU/g in paprika at 24s. EV reduced Salmonella Tennessee by 3 log CFU/g within 120s when applied to inoculated paprika and black pepper without detrimentally affecting spice quality. However, the samples receiving FIR treatments suffered reductions in volatile content and color changes to the spices. High levels (up to 1% w/w) of residual ethanol were also detected on samples treated for 300s. Concluding, both treatment show similar results when comparing efficacy; however, based on the magnitude of change in volatile content associated with FIR being significantly greater than those samples receiving EV, FIR treatment requires additional research before recommending for use with dried, ground paprika, black pepper, or sage.



Spices, Salmonella, Ethanol, Far Infrared Radiation