Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/29/2017
Publication Date: 4/30/2017
Citation: Huang, L. 2017. Growth of Salmonella Enteritidis in liquid egg whites during refrigerated storage and temperature abuse: A one-step dynamic analysis. Meeting Abstract. IAFP [abstract].
Technical Abstract: Introduction: Salmonella Enteritidis is a foodborne pathogen that affects the safety of eggs and egg products. Egg-associated salmonellosis is a serious public health problem in the United States and many parts of the world. Understanding the growth and survival of S. Enteritidis in egg products may help prevent and reduce foodborne salmonellosis. This study was conducted to investigate the growth and survival of this pathogen in liquid egg whites. Methods: Pasteurized liquid egg white samples were inoculated with a 5-strain cocktail of S. Enteritidis and incubated under dynamically changing temperature conditions between 2 and 37 degrees C to observe the growth and survival of the bacterium. Two differential equations were used in combination with the Huang square-root secondary model to describe the growth and survival of S. Enteritidis. A one-step dynamic analysis method was used to determine the kinetic parameters using least squares optimization by minimizing the sum of squared residuals. Results: No lag phase was observed in the growth curves. The growth and survival of S. Enteritidis was accurately analyzed using the one-step dynamic analysis method. The estimated minimum growth temperature (Tmin) of the bacterium was 7.76 degrees C, matching well with the general characteristics of S. Enteritidis. At temperatures below Tmin, the bacteria would die at 0.136 log CFU/g per day per degrees C. For model development, the root mean square error (RMSE) was only 0.43 log CFU/g. About 70% of the residual errors were within 0.5 log CFU/g of observations. For validation, about 69% of the residual errors with within 0.5 log CFU/g of observations. Significance: This study demonstrated that the one-step dynamic analysis is an effective method for studying the growth and survival kinetics of foodborne pathogens. The results obtained from this study can be used to predict the growth of S. Enteritidis in liquid egg whites and to conduct risk assessment of this pathogen.