CUTTING BOARDS OF PLASTIC AND WOOD CONTAMINATED EXPERIMENTALLY WITH BACTERIA

microbiology of plastic and wooden cutting boards was studied, regardi ng cross-contamination of foods in home kitchens. New and used plastic (four polymers plus hard rubber) and wood (nine hardwoods) cutting bo ards were cut into 5-cm squares (''blocks''). Escherichia coli (two no npathogenic strains plus type 0157:H7), Listeria innocua, L. monocytog enes, or Salmonella typhimurium was applied to the 25-cm(2) block surf ace in nutrient broth or chicken juice and recovered by soaking the su rface in nutrient broth or pressing the block onto nutrient agar, with in 3-10 min or up to ca. 12 h later. Bacteria inoculated onto plastic blocks were readily recovered for minutes to hours and would multiply if held overnight. Recoveries from wooden blocks were generally less t han those from plastic blocks, regardless of new or used status; diffe rences increased with holding time. Clean wood blocks usually absorbed the inoculum completely within 3-10 min. If these fluids contained 10 (3)-10(4) CFLT of bacteria likely to come from raw meat or poultry, th e bacteria generally could not be recovered after entering the wood. I f greater than or equal to 10(6) CFU were applied, bacteria might be r ecovered from wood after 12 h at room temperature and high humidity, b ut numbers were reduced by at least 98%, and often more than 99.9%. Mi neral oil treatment of the wood surface had little effect on the micro biological findings. These results do not support the often-heard asse rtion that plastic cutting boards are more sanitary than wood.The micr obiology of plastic and wooden cutting boards was studied, regarding c ross-contamination of foods in home kitchens. New and used plastic (fo ur polymers plus hard rubber) and wood (nine hardwoods) cutting boards were cut into 5-cm squares (''blocks''). Escherichia coli (two nonpat hogenic strains plus type 0157:H7), Listeria innocua, L. monocytogenes , or Salmonella typhimurium was applied to the 25-cm(2) block surface in nutrient broth or chicken juice and recovered by soaking the surfac e in nutrient broth or pressing the block onto nutrient agar, within 3 -10 min or up to ca. 12 h later. Bacteria inoculated onto plastic bloc ks were readily recovered for minutes to hours and would multiply if h eld overnight. Recoveries from wooden blocks were generally less than those from plastic blocks, regardless of new or used status; differenc es increased with holding time. Clean wood blocks usually absorbed the inoculum completely within 3-10 min. If these fluids contained 10(3)- 10(4) CFU of bacteria likely to come from raw meat or poultry, the bac teria generally could not be recovered after entering the wood. If gre ater than or equal to 10(6) CFU were applied, bacteria might be recove red from wood after 12 h at room temperature and high humidity, but nu mbers were reduced by at least 98%, and often more than 99.9%. Mineral oil treatment of the wood surface had little effect on the microbiolo gical findings. These results do not support the often-heard assertion that plastic cutting boards are more sanitary than wood.