Monitoring poultry farms for Salmonella by drag-swab sampling and antigen-capture immunoassay

Drag-swab (DS) sampling, at the rate of four DS gauze pads per flock (house); modified culture procedures (novobiocin-supplemented plating media and delayed secondary selective enrichment); and Salmonella antigen-capture (SAC) technology were combined in screening one layer flock and 38 market-age broiler flocks. The results showed that low (negative) SAC sample-to-positive control (S/P) ratios were related to the negative culture recovery of Salmonella. Similarly, high (positive) S/P ratios were related to and indicative of positive culture recoveries. Extensive sampling and testing of 18 of the 39 flocks disclosed A) that five flocks with negative culture recoveries from feathers and freshly voided feces had essentially no positive DS-SAC values, and B) that 13 flocks with positive culture recoveries from feathers and/or fresh feces all had positive DS-SAC values.