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Dynamic Predictive Model for Growth of Salmonella Enteritidis in Egg Yolk
Author(s) -
Gumudavelli V.,
Subbiah J.,
Thippareddi H.,
Velugoti P.R.,
Froning G.
Publication year - 2007
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2007.00444.x
Subject(s) - salmonella enteritidis , yolk , isothermal process , growth function , mean squared error , exponential function , growth rate , mathematics , growth model , exponential growth , bacterial growth , salmonella , zoology , chemistry , statistics , biology , food science , thermodynamics , physics , mathematical analysis , genetics , geometry , mathematical economics , bacteria
Salmonella Enteritidis (SE) contamination of poultry eggs is a major human health concern worldwide. The risk of SE from shell eggs can be significantly reduced through rapid cooling of eggs after they are laid and their storage under safe temperature conditions. Predictive models for the growth of SE in egg yolk under varying ambient temperature conditions (dynamic) were developed. The growth of SE in egg yolk under several isothermal conditions (10, 15, 20, 25, 30, 35, 37, 39, 41, and 43 °C) was determined. The Baranyi model, a primary model, was fitted with growth data for each temperature and corresponding maximum specific growth rates were estimated. Root mean squared error (RMSE) values were less than 0.44 log 10 CFU/g and pseudo‐ R 2 values were greater than 0.98 for the primary model fitting. For developing the secondary model, the estimated maximum specific growth rates were then modeled as a function of temperature using the modified Ratkowsky's equation. The RMSE and pseudo‐ R 2 were 0.05/h and 0.99, respectively. A dynamic model was developed by integrating the primary and secondary models and solving it numerically using the 4th‐order Runge–Kutta method to predict the growth of SE in egg yolk under varying temperature conditions. The integrated dynamic model was then validated with 4 temperature profiles (varying) such as linear heating, exponential heating, exponential cooling, and sinusoidal temperatures. The predicted values agreed well with the observed growth data with RMSE values less than 0.29 log 10 CFU/g. The developed dynamic model can predict the growth SE in egg yolk under varying temperature profiles.