| 
      
        |  | Inoculation
            (CFU/surface) | Replicates | PDX-LIB | UVM-USDA | χ2 |  
        | Presumptive    Positives | Confirmed    positives | Confirmed    positives |  
        | Lm    21 | 1.50E+05 | 20 | 9 | 9 | 2 | 2.92 |  
        | Lm    42 | 1.30E+05 | 20 | 16 | 16 | 1 | 11.5 |  
        | Lm    & EF on3Stainless    steel | 2.50E+04 | 20 | 18 | 18 | 3 | 10.7 |  
        | Lm    464 | 1.60E+04 | 20 | 10 | 10 | 0 | 6.33 |  
        | Lm    10 &Ec5 onSealed    concrete | 7.20E+02 | 20 | 9 | 9 | 0 | 5.51 |  |