Evaluation of the Thermal Inactivation of a Salmonella Serotype Oranienburg Strain During Cocoa Roasting at Conditions Relevant to the Fine Chocolate Industry

Abstract

Cocoa roasting produces and enhances distinct flavor of chocolate and acts as a critical control point for inactivation of foodborne pathogens in chocolate production. In this study, the inactivation kinetics of <i>Salmonella enterica subsp. enterica</i> serotype Oranienburg strain was assessed on whole cocoa beans using roasting protocols relevant to the fine chocolate industry. Beans were inoculated with 10⁷-10⁸ log₁₀ CFU/bean of <i>Salmonella</i> Oranienburg and roasted at 100-150°C for 2-100 min. A greater than 5 log₁₀ reduction of <i>S.</i> Oranienburg was experimentally achieved after 10-min roasting at 150°C. Data were fitted using log-linear and Weibull models. The log-linear models indicated that the roasting times (<i>D</i>) needed to achieve a decimal reduction of <i>Salmonella</i> at 100, 110, 115, 120, 130, and 140°C were 33.34, 18.57, 12.92, 10.50, 4.20, and 1.90 min, respectively. A Weibull model indicated a decrease in the <i>Salmonella</i> inactivation rate over time (<i>β</i> < 1). Statistical analysis indicated that the Weibull model fitted the data better compared to a log-linear model. These data demonstrate the efficacy of cocoa roasting in inactivation of <i>Salmonella</i> and may be used to guide food safety decision-making.