Decontamination of Plastic and Wooden Cutting Boards for Kitchen Use

Decontamination of Plastic and wooden cutting boards was studied, with a view to preventing cross-contamination of foods in home kitchens. New and used Plastic (four polymers plus hard rubber) and wood (nine hardwoods) boards were cut into 5-cm square blocks (25 cm² area) for these experiments. Bacterial contaminants-- Escherichia coli (two nonpathogenic strains plus serotype O157:H7), Listeria innocua , L. monocytogenes , or Salmonella typhimurium --applied to the block surface in nutrient broth or chicken juice, were recovered by soaking the surface in nutrient broth or pressing the block onto nutrient agar, within minutes or ≥12 h later. Persistence and overnight multiplication of bacteria on plastic surfaces depended on maintenance of humidity so as to prevent drying of the contaminant. New plastic cutting surfaces were relatively easy to clean and were microbiologically neutral, but plastic boards with extensive knife scars were difficult to clean manually, especially if they had deposits of chicken fat on them. Fewer bacteria were generally recovered from wooden blocks than from plastic blocks. Clean wood blocks rapidly absorbed all of the inoculum, after which the bacteria could not be recovered within 3 to 10 min. If the board surface was coated with chicken fat, some bacteria might be recovered even after 12 h at room temperature and high humidity. Cleaning with hot water and detergent generally removed these bacteria, regardless of bacterial species, wood species, and whether the wood was new or used.