Use of active packaging structures to control the microbial quality of a ready-to-eat meat product

Antimicrobial packaging appears to be a promising application of active food packaging technology. This project was undertaken to evaluate the effectiveness of selected antimicrobial packaging structures in improving the microbial quality of a ready-to-eat (RTE) meat product. Cooked ham samples (25 g) inoculated with a five-strain mixture of Listeria monocytogenes (2 or 4 log CFU g(-1)) were packaged into three different antimicrobial packaging structures, respectively, and samples in the non-antimicrobial packaging structure served as controls. The samples were stored at 4, 10, or 22 degrees C, and populations of total aerobic bacteria, Enterobacteriaceae, and inoculated L. monocytogenes were determined twice a week over a 4 w storage period. Packaging structures with an O-2 scavenger or a CO2 generator were more effective than the structure with an allyl isothiocyanate (AIT) generator. Listeria populations in the packaging structure with the O-2 scavenger were 1.80-2.65, 3.69-4.76, and 4.62-4.67 log CFU g(-1) lower than the controls at 4, 10, or 22 degrees C. Samples in the packaging structure with the CO2 generator were 1.11-1.63, 4.30-4.45, and 4.01-4.44 log CFU g(-1) lower than the controls at 4, 10, or 22 degrees C. Significant inhibitions on total aerobic bacteria and Enterobacteriaceae counts were also observed in packaging structures with the CO2 generator and O-2 scavenger. However, packaging structures with the AIT generator only significantly inhibited L monocytogenes, total aerobic bacteria, and Enterobacteriaceae in some samples, mainly those stored at 22 degrees C. These results suggest that some of the evaluated packaging structures can effectively control bacterial populations, particularly Listeria populations on RTE meat products. (C) 2012 Elsevier Ltd. All rights reserved.