National surveillance of Salmonella Enteritidis in commercial eggs in Japan

Abstract

SUMMARYA total of 105 033 eggs were collected across Japan from June 2010 to January 2011 and tested for Salmonella Enteritidis to provide data for the risk profiling of S. Enteritidis in eggs by the Food Safety Commission of Japan. S. Enteritidis isolates were recovered from three samples (20 eggs/sample) and these samples were different in regard to sampling period, grading and packaging centre and farm. The prevalence of S. Enteritidis in commercial eggs in Japan is estimated at ∼0·003% which was a tenfold decrease in prevalence compared to similar surveillance in the mid 1990s. The decrease in the contamination in commercial eggs is considered a contributory factor in the decrease of foodborne diseases associated with S. Enteritidis in this period.

Frequency and Duration of Fecal Shedding of Salmonella Enteritidis by Experimentally Infected Laying Hens Housed in Enriched Colony Cages at Different Stocking Densities

“…Enteritidis exposure dose (21, 30, 31). Commercial laying hens are likely exposed to relatively low doses of salmonellae from environmental sources or via horizontal contact transmission, generally resulting in infrequent infection and egg contamination (9, 32). …”

“…However, the sustained participation of egg producers in comprehensive S . Enteritidis flock testing and risk reduction programs (8) has recently been linked to decreased incidences of both egg contamination and human illness in several nations (9–11). …”

Horizontal transmission of Salmonella Enteritidis in experimentally infected laying hens housed in conventional or enriched cages

“…The frequency and duration of fecal shedding, as well as the likelihood of deposition inside eggs, are directly related to the size of the initial oral dose of Salmonella Enteritidis (Gast and Holt, 2000;Gast et al, 2011bGast et al, , 2013a. Exposure by horizontal contact, the probable mechanism for transmission of most naturally occurring infections within flocks, typically involves low exposure doses and thus leads to correspondingly low overall frequencies of infection and egg contamination (Gast and Holt, 1999;DeWinter et al, 2011;Esaki et al, 2013).…”

“…In the United States, very little overall progress was made in controlling the incidence of infections with Salmonella Enteritidis or other prominent serovars between 1996 and 2010 (Centers for Disease Control and Prevention, 2011;Chai et al, 2012). Substantial public and private resources have been committed to Salmonella Enteritidis testing and risk reduction in egg-laying poultry and the sustained international application of such programs has been followed by reported decreases in the occurrence of both egg contamination (Esaki et al, 2013) and human Salmonella Enteritidis infections (Poirier et al, 2008;O'Brien, 2013). However, active disease surveillance and retrospective epidemiologic analyses document a continuing association between the prevalence of Salmonella Enteritidis in commercial egg flocks and the incidence of human illness (Havelaar et al, 2013;Arnold et al, 2014).…”

Prevention of egg contamination by Salmonella Enteritidis after oral vaccination of laying hens with Salmonella Enteritidis ΔtolC and ΔacrABacrEFmdtABC mutants

“…Eggs were identified as the main food vehicle causing human illness [ 1 , 2 ]. A sustained commitment of the authorities, implementation of Salmonella control programs and serious investment in Salmonella research led to international progress in decreasing the incidence of both egg contamination [ 3 ] and human infections [ 4 ]. Vaccination in particular contributed to the decline in the number of recorded human cases of Salmonella Enteritidis [ 5 ].…”