Growth ofSalmonella enteritidisin artificially contaminated hens' shell eggs

Abstract

SUMMARYThe effect of some factors on the growth of Salmonella enteritidis phage type 4 in artificially contaminated shell eggs was investigated.Salmonella enteritidis was found to be resistant to the antimicrobial properties of the albumen. Growth occurred on storage at 25 'C but not at 4 or 10 'C. The rate and extent of infection was influenced by the size of inoculum, the site of contamination relative to yolk movement, and the presence of iron in the inoculum.

Persistence of contamination of hens' egg albumen in vitro with Salmonella serotypes

“…The studies by Clay and Board [16] demonstrated that, following inoculation of the inner shell membrane of the air cell with S. enteritidis PT4, there were two phases in the infection process of eggs stored at 10 or 25 'C. Persistence of the infection in the shell membrane together with contamination of albumen underlying the membrane with small numbers of quiescent organisms characterized the first phase.…”

“…In contrast, Salmonella enteritidis dominated the infection of both the shell membrane and contents of eggs stored at 37 'C. Clay and Board [16] noted that a pure culture of S. enteritidis was confined to the shell membranes of eggs stored at 4 'C. With storage at ambient temperature, there was a progressive increase in the number of eggs containing > 1.0 x 107 salmonellas per ml of albumen.…”

“…It is evident that further work needs to be done to resolve these conflicting interpretations. The present study, which is a prelude to such investigations, examines the hypothesis that following trans-shell or oviducal infection of infertile hens' eggs the initial invaders of the albumen would not proliferate sufficiently to cause the gross contamination noted by Clay and Board [16].…”

The influence of temperature on the behaviour of mixed bacterial contamination of the shell membrane of the hen's egg

“…To date there appears to have been no detailed study of factors affecting salmonella translocation across the shell. In contrast, much attention has been given recently to the second phase of trans-shell contamination, namely the fate of salmonellas injected into eggs [10,11]. Clay and Board [11] in the shell at the centre of the air cell.…”

“…In contrast, much attention has been given recently to the second phase of trans-shell contamination, namely the fate of salmonellas injected into eggs [10,11]. Clay and Board [11] in the shell at the centre of the air cell. The inner membrane of the air cell was inoculated with 0 1 ml of a mixed culture (details below).…”