TitleDevelopment and validation of a mathematical model for growth of salmonella in cantaloupe
NameLi, Di (author), Schaffner, Donald W. (chair), Chikindas, Michael L. (internal member), Matthews, Karl R. (internal member), Rutgers University, Graduate School - New Brunswick,
Salmonella food poisoning,
DescriptionThe United States is the largest importer of cantaloupes worldwide and domestic consumption of cantaloupe has been increasing steadily. Many salmonellosis outbreaks associated with the consumption of fresh-cut melons have also been reported. Cut melon pieces were most often contaminated due to poor hygienic practices and suffered temperature abuse. The objective of our research was to develop and validate a mathematical model that predicts the growth rate of Salmonella on fresh-cut cantaloupe over a range of storage temperatures. Bacterial growth experiments were conducted, and growth curves were constructed for five temperatures from 4 to 25°C. Exponential growth rates of Salmonella were calculated using DMFit software. The Ratkowsky or square root model was used to describe Salmonella growth rate as a function of storage temperature. Our results show that the levels of Salmonella on fresh-cut cantaloupe with an initial load of ~103 CFU/g can reach over 7 log CFU/g at 25°C within 24h. No growth was observed at 4°C. A linear correlation was observed between Salmonella growth rate vs. temperature: , R² = 0.9779. The model was validated with data collected from experiments conducted with other melon and pathogen combinations and compared with existing models. Our model is consistent with predictions from the ComBase Predictor model. Our research confirms that Salmonella can grow quickly and reach high concentrations when cut cantaloupe is stored at ambient temperatures without visual signs of spoilage. Our model provides a faster and more cost-effective alternative to laboratory studies to estimate the effects of storage temperature on cantaloupe safety and can also be used in subsequent quantitative microbial risk assessments.
NoteIncludes bibliographical references
Noteby Di Li
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.