.

1 1 11 2 1 1 20 3 1 1 75 0 1 2 9.2 1 1 2 15 2 1 2 27 3 1 2 120 0 1 3 12 1 1 3 19 2 1 3 34 3 1 3 160 0 2 0 6.2 1 2 0 11 2 2 0 21 3 2 0 93 0 2 1 9.3 1 2 1 15 2 2 1 28 3 2 1 150 0 2 2 12 1 2 2 20 2 2 2 35 3 2 2 210 0 2 3 16 1 2 3 24 2 2 3 42 3 2 3 290 0 3 0 9.4 1 3 0 16 2 3 0 29 3 3 0 240 0 3 1 13 1 3 1 20 2 3 1 36 3 3 1 460 0 3 2 16 1 3 2 24 2 3 2 44 3 3 2 1100 0 3 3 19 1 3 3 29 2 3 3 53 3 3 3 > 1100

      ^a Confidence intervals are not included to simplify the table (FDA Bacteriological Analytical Manual and other sources).

Figure 3.6 Dilution and inoculation scheme for most probable number technique.

After scoring MPN tubes, the score is converted into an MPN/g food sample using standard MPN tables (Table 3.2). There are equations and computer programs available for calculating MPN; online MPN calculators may also be useful. The MPN table is based on the amount of sample (i.e., food) that is present in the MPN tubes; therefore, column headings of MPN tables are usually