Table 2.

Robustness of bleach sterilization step

E. coli dose	C. sporogenes dose	Growth in Luria broth	Growth in YCFA broth
6.95 × 108	8.79 × 104	No	No
Contamination error	8.79 × 104	No	No
2.23 × 108	8.79 × 104	No	No
2.17 × 1010	8.79 × 104	No	No

The ability of the 25% bleach solution to kill contaminating microbes in the time frame given by the procedure was tested by a spike experiment. K-12 E coli grown at 37°C and 200 rpm for at least 15 h and spores isolated from C. sporogenes were both spiked into eggs isolated by the procedure prior to sterilization. A 250 μL aliquot of both bacterial suspensions was used as the spike volume. A 100 μL aliquot was removed from the eggs before and after the protocol bleach step and subsequent washes and spiked into LB broth aerobically and YCFA broth anaerobically. Unbleached egg sample spikes resulted in growth in both culturing conditions (related to step 4).