Submitted to: Foodinfo News Service
Publication Type: Trade Journal
Publication Acceptance Date: August 2, 2004
Publication Date: August 3, 2004
Citation: Buhr, R.J., Bourassa, D.V., Cason Jr, J.A., Berrang, M.E., Fletcher, D.L. 2004. Detecting low levels of salmonellae from post-chill broiler carcasses. Foodinfo News Service.
In the 1994-1995 FSIS baseline study of Salmonella positive broiler carcasses, 87% had less than 120 cells per carcass, and 42% had less than 12 cells per carcass. The infectious dose for salmonellosis in susceptible humans could be as low as one viable salmonellae cell to colonize the alimentary tract. The ability to detect low levels of salmonellae from poultry carcasses may be necessary if salmonellae-positive carcasses harbor less than 30 salmonellae cells. The objective was to compare the incidence of salmonellae recovery using a rinse aliquot method and a whole carcass enrichment method on carcasses collected immediately after chilling from three commercial plants. To each bag 400 mL of buffered peptone was added, the carcass shaken for one minute, and a 30 mL aliquot was removed for salmonellae recovery (rinse aliquot method). The carcass and the remaining rinsate were aseptically transferred to a new bag and an additional 130 mL of buffered peptone added making a total of 500 mL required for the whole carcass enrichment method (WCE). Both the 30 mL aliquots and carcasses were pre-enriched by incubation at 37 C for 24 h prior to salmonellae detection. Of 120 carcasses, 45 were found to be salmonellae positive using the rinse aliquot method (38%) and 69 were found positive using the whole carcass enrichment method (58%). WCE methodology may not be practical or necessary for everyday detection of salmonellae in poultry processing plants since it requires additional incubation space to contain the rinsate and carcasses. Where WCE may play an important role is in the evaluation of intervention strategies, particularly those that use chemical treatments. The most sensitive methods of salmonellae detection will be necessary to test decontamination methods designed to lower the numbers of this pathogen on poultry.