Effect of grape seed extract on heat resistance of Clostridium perfringens vegetative cells in sous vide processed ground beef

Abstract

The heat resistance (57.5-65 degrees C) of a three-strain cocktail of Clostridium perfringens vegetative cells in sous vide processed ground beef supplemented with 0-3% grape seed extract (GSE) was quantified. The surviving cell population was enumerated on tryptose sulfite cycloserine agar. The decimal reduction (D)-values in beef that included no GSE were 67.11, 17.15, 4.02, and 1.62 min at 57.5, 60, 62.5, and 65 degrees C, respectively. Addition of 1.0% GSE resulted in concomitant decrease in heat resistance as evidenced by reduced bacterial D-values. The D values in beef with added 1.0% GSE were 62.89, 13.70, 3.47 and 1,46 min at 57.5, 60, 62.5, and 65 degrees C, respectively. The heat resistance was further decreased when the GSE concentration in beef was increased to 2 or 3%. The z-values in beef with or without GSE were similar, ranging from 4.41 to 4.56 degrees C. The results of this study would be beneficial to the retail and institutional food service establishments in estimating re-heating time and temperature for sous vide processed ground beef to ensure safety against C. perfringens.