Growth modelling of Listeria monocytogenes in packaged fresh green asparagus

Growth of Listeria monocytogenes in packaged fresh green asparagus was investigated at different temperatures The present study monitored the growth of L. monocytogenes in packaged fresh green asparagus stored at 2, 4, 8, 12 and 20 degrees C. Changes in carbon dioxide, oxygen concentrations and pH were determined. Growth data were fitted to the Baranyi equation The influence of storage temperature was very apparent, at higher temperatures (8, 12 and 20 degrees C) an increase of two logarithmic units of L. monocytogenes took place, criteria used for the determination of the sanitary risk. The recommended storage temperatures for the optimal and safe conservation of asparagus are the lower ones studied (2 and 4 degrees C), because growth of L. monocytogenes is not allowed, although it can survive, so in cases of a high contamination of this micro-organism it could be a sanitary risk. Predictive modelling appears to be a useful tool in estimating growth rates of L. monocytogenes in these products. (C) 2000 Academic Press.