Growth kinetics of Listeria monocytogenes and spoilage microorganisms in fresh-cut cantaloupe

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 43 degrees C, to develop kinetic growth models. During storage studies, the population of both background 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 4 degrees C, 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 monogtogenes inoculated to fresh-cut cantaloupe. The effect of temperature on the growth of L monocytogenes and spoilage microorganisms was evaluated using three secondary models. For L. monocytogenes, the minimum and maximum growth temperatures were estimated by both the Ratkowsky square-root and Cardinal parameter models, and the optimum temperature and the optimum specific growth rate by the Cardinal parameter model. An Arrhenius-type model provided more accurate estimation of the specific growth rate of L monocytogenes at temperatures <4 degrees C. 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 for estimating the shelf-life of fresh-cut products. Published by Elsevier Ltd.