Salmonella in table eggs: occurrence in retails, storage conditions and eggshell disinfections

A survey of the presence of Salmonella in chicken eggshell and yolk, obtained on the retail market in Campinas, SP, Brazil, was carried out in order to study the effect of storage time and temperature on the Salmonella enteritidis (SE) multiplication on the eggshell and yolk of eggs artificially contaminated by contact with litter and, also, the multiplication of SE in egg white, whippet egg white and glace, storage under different conditions of temperature. It was also studied the effect of egg dipping disinfections into two solutions, on the bacterial and SE counting on contaminated eggshell. From the 124 samples tested on the survey, 12 (9.6%) and four (3.2%) were positive for Salmonella on the eggshell and in the yolk, respectively. SE was the only detected sorovar. SE remained viable in artificially contaminated eggshells for a period of 21 days in eggs kept at both room temperature (25ºC), and refrigeration (4-8ºC). Migration of SE from the eggshell to the yolk was detected after 24 hours of storage, under both conditions with a greater level on the eggs kept at room temperature. The refrigerated conditions did not affect SE migration, although its replication was reduced. Egg white, whipped egg white and glace were shown not to be good substrates for SE growth, considering there was a reduction of one log10 titer in the original contamination of these foods, kept under both time conditions (24 and 168 hours for glace) and temperatures. In this study, egg dipping in a warm solution (45ºC) of a commercially available quaternary ammonium compound (400ppm) using the same conditions was more effective in eggshell disinfections than the chlorinated compound (50.2ppm) on the total mesophilic bacteria and SE reduction.

Egg; Salmonella enteritidis; Salmonella spp.; egg disinfection

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