Comparison of different cultural techniques in isolation of Listeria monocytogenes from various samples

Received: 01/03/2014 Revised: 29/03/2014 Accepted: 29/03/2014 Abstract Two different enrichment procedures and plating methods for isolation of Listeria monocytogenes were compared while screening 1878 samples from animals (cattle475 Buffalo-70 and goats 385 ), human beings (240) and from environment (708). The methods of enrichment included a single step enrichment procedure using Buffered Listerial broth (BLEB) and another one with two step enrichment procedure using University of Vermount (UVM) broth. Polymixin Acriflavin Lithium Chloride Ceftazidime Mannitol agar (PALCAM) and Oxford agars were the solid media used. The results of the study showed that the two step enrichment procedure using UVM and PALCAM media combination yielded maximum isolates (4.04 per cent) followed by two step enrichment using UVM and plating to Oxford media (3.35 per cent), single step enrichment using BLEB and plating to PALCAM (2.02 per cent) and finally, single step enrichment using BLEB and plating to Oxford agar (1.91 per cent). The results indicated the superiority of two step enrichment especially when sample contained more background microflora.