Comparison of PCR, electrochemical enzyme-linked immunosorbent assays, and the standard culture method for detecting salmonella in meat products

Abstract

An electrochemical enzyme-linked immunosorbent assay (ELISA) coupled with flow injection analysis (ELISA-FIA) and a PCR-based method using ST11 and ST15 primers for detecting salmonellae in meat were evaluated in comparison with the International Organization for Standardization (ISO) culture method. The methods were applied to experimentally contaminated and naturally contaminated meat samples. The results showed that both ELISA-FIA and PCR allowed detection of salmonella in a product contaminated with a low number of the microorganisms (1 to 10 salmonellae/25 g) after only 5 h of incubation of preenrichment broth, and they were just as effective as the ISO method.

FIG. 1.

Naturally contaminated sample underwent ELISA-FIA (A) and PCR (B) testing after different preenrichment times.(A) The bars represent the standard deviation obtained for the results of three replicates. (B) Lane 1, 100-bp DNA Ladder Plus marker (M-Medical Genenco); lane 2, preenrichment broth aliquot collected after 8 h of incubation; lane 3, preenrichment broth aliquot collected after 6 h of incubation; lane 4, preenrichment broth aliquot collected after 5 h of incubation; lane 5, preenrichment broth aliquot collected after 4 h of incubation; lane 6, preenrichment broth aliquot collected after 2 h of incubation; lane 7, preenrichment broth aliquot collected before incubation (time zero); lane 8, positive control; lane 9, internal control; lane 10, negative control.