Occurrence of Plesiomonas shigelloides in displayed portions of saltwater fish determined by a PCR assay based on the hugA gene.
PCR primers were designed and used to amplify a 435-bp fragment from the Plesiomonas shigelloides hugA gene. The PCR assay combined with a non-selective enrichment step proved to be a reliable procedure for P. shigelloides detection in fish meat. The incidence of this bacterium was investigated in 52 lots of pre-packed saltwater fish portions (conger, swordfish, sole, grouper, whiting and halibut) displayed at two hypermarkets by a conventional two-step procedure and the PCR assay. Using the former, P. shigelloides was isolated from three lots of grouper fillets and one lot of halibut fillets. When PCR was performed with non-selective enriched cultures of fish portions, amplification products were obtained from samples that were positive by the culturing method and from eight additional lots of grouper fillets that gave negative results with the conventional procedure. After a secondary enrichment in tetrathionate broth without iodine, all PCR-positive non-selective enrichments yielded P. shigelloides colonies. Overall, P. shigelloides was found in 23% of the examined lots of marine fish (11 of grouper and one of halibut).
Department of Food Hygiene and Food Technology, University of León, 24071-León, Spain.
Fanny C
FC
Herrera
Jesús A
JA
Santos
Andrés
A
Otero
María-Luisa
ML
García-López
D000818:Animals; D003257:Consumer Product Safety; D004269:DNA, Bacterial / Q000032:analysis*; D005396:Fish Products / Q000382:microbiology*; D005399:Fishes / Q000382:microbiology; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D005784:Gene Amplification; D006801:Humans; D016981:Plesiomonas / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*; D017747:Seafood / Q000382:microbiology
D004269:DNA, Bacterial