Evaluation of method. Using 6 h of resuscitation
when necessary, 58 samples of fresh and
frozen chicken, minced meat, unpasteurized liquid
egg, and desiccated coconut were tested for
the presence of Salmonella by both methods.
The results are given in Table 2, and the ratios
obtained by the radiometric method are shown
in Fig. 5. The most important result of the
comparative testing was that the radiometric
method detected Salmonella in all cases where
Salmonella cells were also isolated by the routine
method. There were five (9%) false positives,
and in only one case was the radioactivity ratio
marginal (Fig. 5). With these samples, particularly
the three meat samples, it was noted that
the number of lactose-fermenting organisms on
the brilliant green agar plus sulfadiaxine plates
were so numerous that it would have been impossible
to detect the typical Salmonella colonies.
Recovery of Salmonella on bismuth sulfite
agar was poor in this study.