Submitted to: Food Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/1/2012
Publication Date: 1/16/2013
Citation: Fang, T., Liu, Y., Huang, L. 2013. Growth kinetics of Listeria monocytogenes and spoilage microorganisms in fresh-cut cantaloupe. Food Microbiology. http://dx.doi.org/10.1016/j.fm.2012.12.05. Interpretive Summary: Listeria monocytogenes is a deadly foodborne pathogen and is a significant public health hazard. A recent multistate outbreak of listeriosis caused by contaminated cantaloupes resulted in 146 illnesses, including 30 deaths and 1 miscarriage. The objective of this research is to investigate the growth kinetics of L. monocytogenes in fresh-cut cantaloupe and develop mathematical models to predict the growth of this pathogen. The results of this research can be used by regulatory agencies to conduct risk assessments of L. monocytogenes in fresh-cut produce.
Technical Abstract: The main objective of this study was to investigate the growth kinetics of Listeria monocytogenes and background microorganisms in fresh-cut cantaloupe. Fresh-cut cantaloupe samples, inoculated with three main serotypes (1/2a, 1/2b, and 4b) of L. monocytogenes, were incubated at different temperatures, ranging from 4 to 43C, to develop kinetic growth models. During storage studies, the population of both background spoilage microorganisms and L. monocytogenes began to increase almost immediately, with little or no lag phase for most growth curves. All growth curves, except for two growth curves of L. monocytogenes 1/2a at 4C, developed to full curves (containing exponential and stationary phases), and can be described by a 3-parameter logistic model. There was no significant difference (P = 0.28) in the growth behaviors and the specific growth rates of three different serotypes of L. monocytogenes inoculated to fresh-cut cantaloupe. The minimum, optimum, and maximum growth temperatures and the optimum specific growth rate of spoilage microorganisms and L. monocytogenes in cantaloupe were estimated by the Ratkowsky square-root model, Cardinal model, and Arrhenius-type model, respectively. The kinetic models developed in this study can be used by regulatory agencies and food processors for conducting risk assessment of L. monocytogenes in fresh-cut cantaloupe, and estimate the shelf-life of fresh-cut products.