Tempo de penetração da Salmonella Heidelberg através da casca de ovos comerciais brancos e vermelhos

Abstract

This study aimed to determine the minimum time after the contact of commercial white and red eggs with material contaminated by Salmonella Heidelberg and its penetration to the inner side of the eggs. White and red eggs recently collected from among layer hens aged between 45 50 weeks, proceeding from a commercial farm in Uberlândia MG, were artificially contaminated by contact with wettish ribbands in inoculated liquid at a stagnant phase of growth (103-104 UFC.g-1 of Salmonella Heidelberg). In the study of each kind of egg, the eggs were subdivided into the following groups: the negative control (without artificial contamination), the positive control (analyzed externally after contamination and internally after the maximum period of maintenance of the test group) and the test group, four repetitions were conducted. The eggs of the test group were maintained at temperature between 25ºC and 30ºC and its contents were analyzed after 60, 90, 120, 150, 180, 210 and 240 minutes, as for the presence of Salmonella in 25g of sample. Each sample unit was compounded of five eggs. The analysis protocol used was the traditional one with pre-enrichment, selective enrichment, plateled in selective agar, biochemical and serological tests. The results obtained were submitted to logistics regression that indicated that the presence of Salmonella Heidelberg in the inner side of the red eggs happens after 168 minutes of contact and in the white eggs after 141 minutes of contact.