Survey of Enterobacteriaceae contamination of table eggs collected from layer flocks in Australia

• Published in: International journal of food microbiology Vol. 164; no. 2-3; pp. 161 - 165
• Main Authors: Gole, V.C., Chousalkar, K.K., Roberts, J.R.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 17.06.2013; Elsevier
• Subjects: Animals; Australia; Bacterial Load; Biological and medical sciences; Chickens; Citrobacter; Citrobacter - isolation & purification; Egg and egg product industries; Egg Shell - microbiology; Eggs; Eggs - microbiology; Enterobacter; Enterobacter - isolation & purification; Enterobacteriaceae; Enterobacteriaceae - classification; Enterobacteriaceae - isolation & purification; Escherichia; Food industries; Food Microbiology; Fundamental and applied biological sciences. Psychology; Genes, Bacterial; Hens; Klebsiella; Kluyvera; PCR; Salmonella; Salmonella - classification; Salmonella - genetics; Salmonella - isolation & purification; Salmonella enterica; Salmonella enterica - genetics; Salmonella enterica - isolation & purification; Salmonella infantis; Serratia; Yersinia; Australia; Oceania; Hens; Salmonella; Eggs; PCR; Enterobacteriaceae; Egg; Contamination; Hen; Polymerase chain reaction; Vertebrata; Survey; Surveillance; Egg product; Bacteria; Aves; Molecular biology
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2013.04.002

In the present study, eggs from commercial caged layer flocks at different stages of lay in Australia were collected. Enterobacteriaceae populations from eggshell surface and eggshell pore were enumerated and these populations characterized using API® Rapid 20E strips. The eggshell surface, eggshell pore and egg internal content samples were also processed for the isolation of Salmonella and these isolates were tested for the presence or absence of several virulence genes (prgH, sopB, spiC, orfL, invA, sifA, sitC, misL). Results indicated that there was no significant difference in total Enterobacteriaceae count on the eggs of the flock from early, mid or late lay flocks. Enterobacteriaceae isolates were of 11 different genera which included: Cedecea, Citrobacter, Enterobacter, Escherichia, Klebsiella, Kluyvera, Leclercia, Pantoea, Salmonella, Serratia and Yersinia. Out of all 153 identified Enterobacteriaceae isolates, the Escherichia genus was reported most frequently (60.78%). Results also indicated that overall there were 4.51% (14/310) Salmonella positive pooled samples. In this study, 14 Salmonella strains were isolated, serotyping confirmed that 12 out of them were Salmonella Infantis and the 2 others were Salmonella enterica subsp. enterica serovar 4,12:d: Polymerase chain reaction results indicated that all Salmonella Infantis isolates harboured invA, misL, orfL, prgH, sifA, sitC, sopB and spiC genes which suggests that Salmonella Infantis strains isolated from eggshell surface may have the capacity to invade and survive in macrophages. •Enterobacteriaceae isolates were of 11 different genera•Salmonella Infantis and Salmonella ser 4, 12d were isolated from eggs.•All Salmonella Infantis isolates harboured invA, misL, orfL, prgH, sifA, sitC, sopB and spiC genes.