Comparison of drag-swab environmental protocols for the isolation of Salmonella in poultry houses

Three surveys were conducted during November 1995 and March and May 1996 to compare the use of double-strength skim milk (wet) or no transport media (dry) drag swabs for the detection of salmonellae in 10 broiler houses. Salmonellae were isolated from 57 of 120 individual wet drag-swab samples, compared with 21 of 120 dry drag-swab samples. Furthermore, Salmonella was detected at a higher frequency with wet drag swabs (66.7%) than with dry drag swabs (40%) when compared on an individual growout house basis. A total of seven different serotypes were isolated from the 10 broiler houses. Although double-strength skim milk drag swabs are more labor intensive than dry drag swabs, double-strength skim milk drag swabs are more efficient for detecting Salmonella than are dry drag swabs with no transport media.