Plastics in which cornstarch is incorporated into the polymer network have been developed. The effect of cornstarch in plastic film on the survival of spoilage and pathogenic bacteria was evaluated. Cornstarch-containing polyethylene film (CSPE) and control polyethylene film (PE) were inoculated with Salmonella typhimurium, Aeromonas hydrophila, Bacillus cereus, and Pseudomonas fragi and held under various combinations of temperature and relative humidity to mimic food storage conditions. Bacterial recovery from film samples indicated that, in general, survival was not enhanced by the presence of cornstarch. Enhanced growth of S. typhimurium, A. hydrophila, and P. fragi was observed under saturated relative humidity at some storage temperatures when a CSPE-supplemented minimal salts medium was used as compared to PE-supplemented medium. Enhanced growth was not apparent when a nutritionally complex growth medium supplemented with CSPE or PE was used. These results indicated that, from a microbiological viewpoint, cornstarch-containing polyethylene film could be successfully used to package foods.
Published as paper No. 19656 of the contribution series of the Minnesota Agricultural Experiment Station based on research conducted under project 18-5, supported by Hatch Funds and by funds from the Agricultural Utilization Research Institute, Crookston, Minnesota.