Perform the 5-tube MPN Presumptive and Confirmed Test for Fecal Coliforms in Shellfish as described above in Section 3, except use EC-MUG tubes instead of EC for the confirmed test. Determination of fluorescence in EC-MUG broth requires the use of 3 control tubes, one inoculated with E. coli as positive control; one with Enterobacter aerogenes (ATCC 13048) or K. pneumoniae as negative control; and an uninoculated tube as EC-MUG medium batch control. Inoculate the positive and negative controls at the time when Confirmed test is being performed and incubate all tubes at 44.5°C ± 0.2°C for 24 h.