Utilization of zein coating and sorbic acid to reduce Listeria monocytogenes growth on cooked sweet corn

Several proteins, lipids and waxes were tested as edible coatings on sweet corn. Only zein, a natural constituent of corn, gave a continuous adhesive and stable coating with satisfactory sensory properties. After 8 days at 10 degreesC, the population of L. monocytogenes was 10-fold lower on coated sweet corn than on non-coated sweet corn indicating a barrier effect of zein coating. Sorbic acid was incorporated in the coating at a concentration required to inhibit L. monocytogenes growth (approximately 1 mg sorbic acid/g of sweet corn). The inhibitory concentration was the same for both coated and non-coated sweet corn. Zein coating therefore did not improve the preservative effect of sorbic acid.