Salmonella carriage and change in serovar distribution in broiler giblets at slaughterhouse level in turkiye: First report using iso 6579-1: 2017 and iso 6579-3: 2014

Abstract

This study aimed to determine the prevalence and serovar distribution of salmonellae in liver, heart, and spleen ( LHS ) and gizzard ( G ) of slaughtered broilers. For this, a total of 60 sample units, comprised of 30 LHS and 30 G collected from 3 slaughterhouses, were analysed by reference methods for detection and serotyping as revised ISO 6579-1:2017 and ISO 6579-3:2014, respectively. Also, Salmonellaspecific real-time PCR ( Salm-PCR ) was used for species confirmation, while Salmonella Enteritidis ( S . Enteritidis ) and Salmonella Typhimurium ( S . Typhimurium ) specific real-time PCR (SE/ST-PCR) was evaluated to determine its efficiency for rapid detection of the serovars mandated in current legal regulations compared to standard serotyping. All LHS (100% -30/30) and 90% (27/30) of G samples harbored Salmonella with an overall prevalence of 95% (57/60) in samples examined, where all isolates were confirmed as Salmonella by Salm-PCR. The most prevalent serovar in broiler giblets was S. Virchow (80.70% -46/57) followed by S. Enteritidis (19.30% -11/57). SE/STPCR (%17.54 -10/57) could not detect one G isolate, which was serotyped as S. Enteritidis by standard serotyping. High relative accuracy (98.25%), sensitivity (100%) and specificity (100%), and agreement between methods ( K : 0.94) verified SE/ST-PCR 's potential to be used as an alternative in rapid detection of S . Enteritidis and S . Typhimurium. Data on high Salmonella prevalence in broiler giblets of slaughterhouse origin, and detection of the pathogen by the implementation of all requirements indicated in the revised ISO 65791:2017 standard method, enabling the determination of actual prevalence in the samples with high sensitivity and specificity is of significance for public health. Additionally, identification of S . Virchow as the dominant serovar followed by S . Enteritidis with a relatively lower prevalence, and absence of S. Typhimurium in broiler giblets are important findings for Turkiye. This up to date data, obtained by strict application of ISO 6579-3:2014 procedures, indicated a shift in circulating serovars in the broiler industry. The objective findings in this study would bring awareness to national/international literature, and may be of use in future improvements in legal regulations.