Figure 6.

Effect of pre-exposure of bacterial parent cultures to coin metal (Australian $1) prior to survival on the same coinage. (A) L. monocytogenes; ○ non-exposed culture; ● pre-exposed culture; (B) E. coli; □ non-exposed culture; ■ pre-exposed culture. The bacterial inoculum in this experiment was facilitated by introducing a fixed aliquot of bacterial suspension to one side (heads only) of sterile coins. Data shown are the average and standard deviation of recoverable bacteria after a single extraction (n = 6).