MICROBIAL INTERACTIONS AND INTERVENTIONS TO REDUCE TRANSMISSION OF FOODBORNE PATHOGENS THROUGH POULTRY
Location: Food and Feed Safety Research
Title: Molecular analysis of Salmonella serotypes at different stages of commercial turkey processing
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 15, 2010
Publication Date: April 1, 2010
Citation: Anderson, P., Hume, M.E., Byrd II, J.A., Hernandez Jr., C.A., Stevens, S., Stringfellow, K., Caldwell, D. 2010. Molecular analysis of Salmonella serotypes at different stages of commercial turkey processing. Poultry Science. 89:2030-2037.
Interpretive Summary: Salmonella isolates were collected from two commercial turkey processing plants (A and B) located in different US geographical locations. Isolates recovered at different stages of processing were subjected to two molecular techniques to determine their usefulness in identifying different types of Salmonella. Samples were collected from four sites in Plant A and five sites in Plant B. Four Salmonella types were identified in Plant A and ten types were identified in Plant B. One Salmonella type in Plant A accounted for 83% of the Salmonella collected, while another Salmonella type was the most common type (39%) recovered in Plant B. Both molecular techniques were able to distinguish Salmonella types. However, one technique was more discriminating than the other. The least discriminating technique failed, upon analysis, to group all like Salmonella types together. The results of the study suggest that these two molecular techniques can be very useful in discriminating Salmonella types collected from the processing plant environment of commercial poultry production. These molecular techniques may offer more cost-effective means to identify Salmonella types from large numbers of isolates and with more immediate results than currently achieved with conventional typing techniques. This information is of interest to researchers and producers of animal food sources desiring more economical, high-throughput, and faster Salmonella typing methods.
Salmonella isolates were collected from two commercial turkey processing plants (A and B) located in different US geographical locations. Isolates recovered at different stages of processing were subjected to two genotype techniques (polyacrylamide gel electrophoresis [PAGE] and denatured gradient gel electrophoresis [DGGE]) to determine their usefulness in Salmonella serotyping. Primers used for PCR amplification were to a highly conserved spacer region located between the 16S and 23S rDNA genes. Sampling sites at Plant A were 1) post-scald, 2) pre-inside-outside bird wash (IOBW), 3) post-IOBW, and 4) post-chill with n = 30, 44, 36, and 12 Salmonella isolates recovered, respectively. Plant B sampling locations were 1) pre-scald, 2) post-scald, 3) pre-IOBW, 4) post-IOBW, and 5) post-chill with n = 16, 54, 24, 35, and 24 Salmonella isolates recovered, respectively. In plant A, four different Salmonella serotypes were identified: Derby, Hadar, Montevideo, and Senftenberg. In plant B, ten serotypes were identified: Agona, Anatum, Brandenburg, Derby, Hadar, Meleagridis, Montevideo, Reading, Senftenberg, and Typhimurium. S. Derby was predominant in Plant A (83%), while S. Typhimurium was the most common serotype recovered in Plant B (39%). Genotype analyses of the Salmonella serotypes were expressed in dendrograms with comparisons interpreted as percentage similarity coefficients. Both PAGE and DGGE were able to distinguish serotype band patterns. However, DGGE was more discriminating than PAGE. Isolates of the same serotypes were grouped together on the dendrogram of band patterns generated by DGGE. In contrast, PAGE failed to group all like serotypes together on the corresponding dendrogram. The results of the study suggest that genotyping techniques can be very useful in discriminating Salmonella serotypes collected from the processing plant environment of commercial poultry production. These molecular techniques may offer more cost effective means to identify Salmonella serotypes from large numbers of isolates and with more immediate results than currently achieved with conventional typing techniques.