Effect of Ethanol Vapor Fumigation on Survival of Salmonella enterica biofilms on Whole Black Peppercorns

Abstract

Salmonella embedded biofilms were formed on whole black peppercorns and treated with ethanol vapor under atmospheric pressure conditions and under vacuum assisted pressure conditions. The effect of ethanol vapor, heat and vacuum pressure on the survival of multiple Salmonella enterica serovars within a biofilm contained on low moisture food products (Aw 0.30-0.40) was observed in this study. Samples were exposed to zero, one, five and ten minute ethanol vapor treatments at atmospheric boiling temperature (Atmospheric Pressure Boiling Method, AB), and at reduced temperature and pressure conditions, -20 inHg (Vacuum-Assisted Boiling Method, VB). The AB treatments showed 4.0 log CFU/g reductions on nonselective media that included native microbiota, and 6.0 log CFU/g reductions on Salmonella selective media. The VB treatments showed 2.69 log reductions on Tryptic Soy Agar and 4.55 log reductions on Xylose Lysine Tergitol-4 agar. Ethanol vapor treatments should be further investigated as an alternative to ethylene oxide or ionizing radiation processes to treat dry spices to control Salmonella.