Antimicrobial efficiency and sorbic acid migration from active films into pastry dough

Antimicrobial films of 25 and 70 mu m thickness, incorporated with 7 and 3% sorbic acid, respectively, were layered with pastry dough without additive and evaluated for sorbic acid migration and antimicrobial efficiency. Pastry dough containing potassium sorbate layered with low-density polyethylene films (LDPE) was used as a control. The films/pastry sandwiches were stored in LDPE bags at 8 +/- 1 degrees C. After 40 days of storage, the dough layered with 25 mu m/7% films showed a reduction of 2log cycles in the aerobic mesophilic count; however, there were no significant differences (p >= 0.05) for the psychotropic and Staphylococcus spp. counts. For the dough layered with 70 mu m/3% films there were reductions of 2 and 1.5log cycles in the mesophilic and psychotropic counts, respectively. In the control dough, the aerobic mesophilic, psychotropic and Staphylococcus spp. counts increased by 1.5, 1 and 2log cycles, respectively. Regardless of the film, the counts of filamentous fungi, yeasts and coagulase-positive staphylococcus were < 1.0 x 10(2)CFU/g, whereas the coliform counts at 35 and 45 degrees C, and Escherichia coli were < 3.0 x 10 degrees NMP/g. The diffusion coefficients of the sorbic acid from the films into the dough had values in the order Of 10(-18)m(2)/s. There were no differences (p >= 0.05) between migration values among the films. The maximum additive release from the 25 mu m/7% film into the dough after 20 days was 0.07%, and from the 70 mu m/3% film after 9 days was 0.09%. Both values are below the maximum limit allowed by current legislation. Copyright (c) 2007 John Wiley & Sons, Ltd.