Heat Resistance of G. Stearothermophilus and C. Sporogenes in Carrot and Meat Alginate Purees

Abstract

The main objective of this study was to investigate the heat resistance of nonpathogenic, heat‐resistant Geobacillus stearothermophilus and Clostridium sporogenes spores in meat and carrot alginate purees. Alginate is used as a viscosity modifier in liquid foods and has been used to fabricate thermally stable and firm simulated particles for biological validation studies of thermal processing, when conventional temperature gathering is not possible. Pureed carrot and meat were mixed with sodium alginate and inoculated with high concentrations of spores of G. stearothermophilus or C. sporogenes and filled into capillary tubes, flame sealed and heat treated in an oil bath for different times at selected temperatures. D values were computed from the slopes of log(N/N0) versus time, and z values from log(D) versus temperature curves. For meat alginates, D values for G. stearothermophilus ranged between 1.9 min and 40.8 min with a z value of 11.7C and D values for C. sporogenes ranged between 0.9 min and 28.7 min with a z value of 10.1C. For carrot alginates, D values for G. stearothermophilus ranged between 1.9 min and 42.6 min with a z value of 11.5C and D values for C. sporogenes ranged from 1.1 min and 31.0 min with a z value of 10.2C. The results were also fitted to Weibull model, but the model did not result in any better fit than the conventional first‐order model. PRACTICAL APPLICATIONS Thermal process establishment is generally based on gathered time temperature data from test cans under real processing conditions. There are many situation like aseptic processing, continuous flow biaxial rotary processing, etc. in which such temperature measurements are often difficult. Biological validation is generally considered useful in such processes to validate the processes as well as computer simulations. Such concepts have been tried to some limited extent in the past. With new thermal processing equipment and processes surfacing time and again, such concepts need to be redesigned. In order to successfully use such applications, thermal destruction kinetics data under controlled conditions are needed. This study provides thermal destruction kinetics baseline data for one such study making use of alginate‐impregnated meat and carrot‐simulated particles. Further, the study compare two modeling procedures: the conventional first‐order log‐linear model versus the log‐nonlinear Weibull models.

Evaluation of thermal destruction kinetics of Clostridium difficile spores (ATCC 17857) in lean ground beef with first‐order/Weibull modeling considerations

“…Hassan and Ramaswamy () reported that the β values were nearly 1.0 for all data sets except C. sporogenes in meat alginates, indicating suitability of log‐linear survivor curves. The Weibull model was found to be no better than the first‐order model for C. sporogenes and G. stearothermophilus .…”

“…Hence, the first-order model was considered to be more accurate and to give more conservative estimates of process times contributing to safer processes. Hassan and Ramaswamy (2011) reported that the β values were nearly 1.0 for all data sets except C. sporogenes in meat alginates, indicating suitability of log-linear survivor curves. The Weibull model was found to be no better than the first-order model for C. sporogenes and G. stearothermophilus.…”

Study of the combined effect of electro-activated solutions and heat treatment on the destruction of spores of Clostridium sporogenes and Geobacillus stearothermophilus in model solution and vegetable puree

“…Regression lines were established for each time temperature combination and individual D values were deduced as the inverse negative of the slope of the fitted curve, the coefficients of determination for individual survivor curves was also analyzed ( Table 4). It was noted that the survivor curves could be generally described by the first-order linear regression model with the coefficients of determination (R 2 ) above 0.8 [29]. In this study, the plotted curves of on the heat resistance of the spores, more specifically, the extract was more effective in reducing the spore count at high temperatures (Figs.…”

Dynamics of Microbial Inactivation and Acrylamide Production in High-Temperature Heat Treatments

“…To estimate the model parameters, several D-values (n = 113) for thermal inactivation of Geobacillus stearothermophilus were collected from the literature (Web of Science database) as described in [41]. A temperature range between 97.5 • C and 137.5 • C was considered, and only food matrixes (especially vegetable-based) were included [38,[42][43][44][45][46][47][48][49][50]. Non-linear regression was applied to obtain mean log 10 D(T re f )-values and z-values with their respective standard errors.…”