Comparison of culture, polymerase chain reaction (PCR), TaqMan Salmonella, and Transia Card Salmonella assays for detection of Salmonella spp. in naturally-contaminated ground chicken, ground turkey, and ground beef.

Four types of assays were evaluated for the detection of Salmonella spp. in retail ground chicken (86 packages), ground turkey (104 packages), and ground beef (54 packages). Two 25 g samples from each package were separately subjected to pre-enrichment in buffered peptone water for 20 h at 37 degrees C followed by enrichment in Rappaport Vassiliadis (RV) broth for 20 h at 42 degrees C. The RV enrichments were plated onto Rambach agar, Rainbow Agar Salmonella, and XLT4 agar, and were also tested by a PCR assay targeting the Salmonella invA gene, as well as by the TaqMan Salmonella PCR assay. Additionally, the RV enrichments were tested using the Transia Card Salmonella immunoassay. Results showed that 16.8, 24.0, 28.8, and 26.4% of turkey samples were positive for Salmonella spp. by culture, PCR, TaqMan PCR, and Transia Card Salmonella assays, respectively. Eighteen, 28.5, 35.5, and 34.9% of chicken samples were positive by culture, PCR, TaqMan PCR, and Transia Card Salmonella assays, respectively, and 6.5, 6.5, 6.5, and 18.5% of ground beef samples were positive by the four assays, respectively. Analysis of the data using the kappa statistic showed that there was substantial to excellent agreement between the PCR and TaqMan PCR assays and between the PCR and culture assays (kappa coefficients ranging from 0.67 to 0.87), while there was poor to fair agreement between the results of the Transia Card Salmonella assay and the other methods (kappa coefficients ranging from 0.28 to 0.32). Overall, results showed that the PCR-based assays were more sensitive than the culture method, and the culture and PCR-based assays were more specific than the immunoassay for detection of Salmonella in ground chicken, turkey, and beef due to the occurrence of false positive results using the immunoassay.

[1]  J. Fleiss.  Statistical methods for rates and proportions , 1974 .

[2]  W. Hill,et al.  Testing for Salmonella in raw meat and poultry products collected at federally inspected establishments in the United States, 1998 through 2000. , 2002, Journal of food protection.

[3]  L. Petersen,et al.  An outbreak of Salmonella blockley infections following smoked eel consumption in Germany , 2000, Epidemiology and Infection.

[4]  S. Craven,et al.  Serotype tracking of Salmonella through integrated broiler chicken operations. , 2002, Journal of food protection.

[5]  A. Rambach.  New plate medium for facilitated differentiation of Salmonella spp. from Proteus spp. and other enteric bacteria , 1990, Applied and environmental microbiology.

[6]  S. Coates,et al.  Performance tested method certification of BAX for Screening/Salmonella: a case study. , 1998, Journal of AOAC International.

[7]  R. Betts,et al.  Comparison of methods for the recovery and detection of low levels of injured Salmonella in ice cream and milk powder , 2000, Letters in applied microbiology.

[8]  T. Hammack,et al.  Relative effectiveness of selenite cystine broth, tetrathionate broth, and Rappaport-Vassiliadis medium for the recovery of Salmonella from raw flesh and other highly contaminated foods: precollaborative study. , 1995, Journal of AOAC International.

[9]  M. T. Destro,et al.  Detection of Salmonella in foods using Tecra Salmonella VIA and Tecra Salmonella UNIQUE rapid immunoassays and a cultural procedure. , 2002, Journal of food protection.

[10]  A. Eyigor,et al.  Implementation of real‐time PCR to tetrathionate broth enrichment step of Salmonella detection in poultry , 2002, Letters in applied microbiology.

[11]  W H Andrews,et al.  Relative effectiveness of selenite cystine broth, tetrathionate broth, and rappaport-vassiliadis medium for recovery of Salmonella spp. from raw flesh, highly contaminated foods, and poultry feed: collaborative study. , 1996, Journal of AOAC International.

[12]  A. Holck,et al.  Application of 5′-Nuclease PCR for Quantitative Detection of Listeria monocytogenes in Pure Cultures, Water, Skim Milk, and Unpasteurized Whole Milk , 2000, Applied and Environmental Microbiology.

[13]  D. Wareing,et al.  Detection of Campylobacter jejuni and Campylobacter coli in foods by enrichment culture and polymerase chain reaction enzyme-linked immunosorbent assay. , 2002, Journal of food protection.

[14]  M. Vainstein,et al.  Influence of enrichment media and application of a PCR based method to detect Salmonella in poultry industry products and clinical samples. , 2001, Veterinary microbiology.

[15]  E. Mallinson,et al.  Xylose-lysine-tergitol 4: an improved selective agar medium for the isolation of Salmonella. , 1991, Poultry science.

[16]  W. Grove.  Statistical Methods for Rates and Proportions, 2nd ed , 1981 .

[17]  L. McCaig,et al.  Food-related illness and death in the United States. , 1999, Emerging infectious diseases.

[18]  P. Fratamico,et al.  Simultaneous detection of Salmonella spp and Escherichia coli O157:H7 by multiplex PCR , 1998, Journal of Industrial Microbiology and Biotechnology.

[19]  U. Bauer,et al.  [Centers for Disease Control and Prevention (CDC)]. , 2000, Annales de dermatologie et de venereologie.

[20]  D. Bolton.  The microbiological safety and quality of foods processed by the "sous vide" system as a method of commercial catering , 1998 .

[21]  L. Slutsker,et al.  A multistate outbreak of Salmonella enterica serotype Baildon associated with domestic raw tomatoes. , 2001, Emerging infectious diseases.

[22]  S. Flood,et al.  Evaluation of TaqMan PCR assay for detecting Salmonella in raw meat and shrimp. , 1999, Journal of food protection.

[23]  S. Ladely,et al.  Comparison of methods for isolating Salmonella bacteria from faeces of naturally infected pigs , 2000, Journal of applied microbiology.

[24]  W Schlosser,et al.  Analysis of Salmonella serotypes from selected carcasses and raw ground products sampled prior to implementation of the Pathogen Reduction; Hazard Analysis and Critical Control Point Final Rule in the US. , 2000, International journal of food microbiology.

[25]  R. Betts,et al.  Comparison of two commercial preparations of buffered peptone water for the recovery and growth of Salmonella bacteria from foods , 2000, Journal of applied microbiology.

[26]  K. Klontz,et al.  Recalls of foods and cosmetics due to microbial contamination reported to the U.S. Food and Drug Administration. , 2000, Journal of food protection.