Inadequacy of selective plating media in field detection of Salmonella

Salmonella is an important human enteropathogen associated with poultry. Po ultry is routinely analyzed for Salmonella by industry, regulatory, and res earch laboratories. Effectiveness of selective plating media is critical to Salmonella laboratory analysis. Many media routinely used in the food micr obiology laboratory were developed for all Gram-negative human enteric path ogens encountered in a clinical laboratory, rather than for Salmonella alon e. The presence of extraneous, non-Salmonella bacteria make the recognition of Salmonella on these plates very difficult. This, more than any other fa ctor, contributes to poor performance of a medium. Primarily because of the poor performance of many selective agars in detecting Salmonella from non- clinical samples, food microbiology laboratories usually use two or more pl ating media to reduce false negative results.