Modeling the growth of Listeria monocytogenes in pasteurized white asparagus.

TítuloModeling the growth of Listeria monocytogenes in pasteurized white asparagus.
Publication TypeJournal Article
Year of Publication2007
AuthorsValero, A, Carrasco, E, Pérez-Rodríguez, F, García-Gimeno, RM, Zurera, G
JournalJ Food Prot
Volume70
Issue3
Pagination753-7
Date Published2007 Mar
ISSN0362-028X
Palabras claveAsparagus Plant, Colony Count, Microbial, Food Microbiology, Food Preservation, Kinetics, Listeria monocytogenes, Models, Biological, Predictive Value of Tests, Temperature, Time Factors
Abstract

Growth of Listeria monocytogenes in pasteurized white asparagus was monitored at different storage temperatures (4, 10, 20, and 30 degrees C). Among the main microbial kinetic parameters, growth rate (mu) per hour was calculated at each temperature using the Baranyi-Roberts model. L. monocytogenes was able to grow at all temperatures, although at 4 degrees C only a slight increment of the microbial population was observed (approximately 1 log CFU/g) after 300 h of storage. Subsequently, two different secondary modeling approaches were proposed to study the relationship between mu and storage temperature: the Arrhenius and Ratkowsky models. Although both models properly described the data observed, smaller values of root mean square error (RMSE) and standard error of prediction (SEP) were obtained with the Ratkowsky model, providing a better goodness of fit (Ratkowsky model: RMSE = 0.010, SEP = 21.23%; Arrhenius model: RMSE = 0.026, SEP = 54.37%). The maximum population density (MPD) was calculated at each temperature studied. A clear dependence between MPD and temperature was found; lower temperatures produced lower values of MPD. This finding confirmed the Jameson effect, indicating that multiple hurdles in the food-processing chain plus lower temperatures reduced L. monocytogenes growth. Predicting the growth of L. monocytogenes along the food chain will help to reduce microbial risks associated with consumption of pasteurized white asparagus.

Alternate JournalJ. Food Prot.