INFLUENCE OF ENRICHMENT INCUBATION-TIME ON THE ISOLATION OF SALMONELLA

The optimum incubation times for Salmonella enrichment cultures were d etermined by inoculation of enrichment broths onto plating media after 24 hours at 37 C, after 48 hours at 37 C, after a 3-day delayed secon dary enrichment (DSE), and after a 5-day DSE procedure. The results sh owed a step-wise increase in Salmonella isolations with the longer inc ubation times. Inoculation of the enrichment broths onto plating media after 24 hours incubation followed by a 5-day DSE made possible the d etection of 96% to 98% of the Salmonella-positive samples and was the best combination of conditions.