Response Surface Plots for the Behavioral Pattern of Yersinia enterocolitica in Chocolate Milk as Affected by Trans-Cinnamaldehyde, a Spice Essential Oil Constituent

Abstract

Response surface plots were generated to determine the behavior of a native food isolate of Yersinia enterocolitica CFR 2301 in chocolate milk with added trans-cinnamaldehyde, an active spice essential oil constituent. The minimum inhibitory and bactericidal concentrations (MIC and MBC) for Y. enterocolitica in broth systems were 0.1 and 0.3 µl/ml, respectively, while in chocolate milk, the MBC was 0.9 µl/ml. In chocolate milk devoid of cinnamaldehyde, the culture of Y. enterocolitica CFR 2301 was able to reach risk-causing population levels in 12 h at 30 °C. In the presence of cinnamaldehyde, an inactivation model was generated for the behavior of Y. enterocolitica in chocolate milk, which revealed that, irrespective of initial inoculum levels, the death time (DT) was primarily influenced by trans-cinnamaldehyde concentrations and incubation temperatures. The death times were found to decrease with higher cinnamaldehyde concentrations and incubation temperatures. Validation of the model revealed the adequacy of predictions derived for this inactivation model and potential application of compatible possibility to develop food formulations with inhibitory principles.