Effect of ripeness stage during processing on Listeria monocytogenes growth on fresh-cut

Abstract

There are several factors that affect the shelf life of fresh-cut fruit, including the cultivar, the ripeness stage of the fruit during processing and the fruit's storage atmosphere and temperature. The effect of fruit ripeness during processing on the survival and growth of Listeria monocytogenes on fresh-cut 'Conference' pear slices at different temperatures (5, 10 and 20 °C) was studied. The four ripeness stages studied in this work (assessed by a fruit's firmness) were mature-green (54<br>60 N), partially ripe (43<br>53 N), ripe (31<br>42 N) and overripe (<31 N). In our studies, pH, acidity and soluble solids content did not significantly change during conditioning at 20 °C. L. monocytogenes grew under all experimental conditions, showing an increase of approximately 2 log CFU g−1 after 8 days of storage at 5 °C. There were significant differences in the L. monocytogenes population between different ripeness stages at the end of the experiments at 10 and 20 °C. Regardless of the ripeness stage of a fresh-cut pear, the growth potential of L. monocytogenes increased with increasing temperature. A pear's ripeness stage during processing is an important consideration to ensure the quality of a fresh-cut pear, but it is not as important for preventing L. monocytogenes growth at common storage temperatures.

The authors are grateful to the University of Lleida, Grupo Alimentario Citrus and Banco Santander for Pilar Colas Meda PhD grant (UdL-Impuls Program) and to the Spanish Government(Ministerio de Economia y Competitividad, research project AGL- 2012-38671) for its financial support.