Validation of Cooking Methods Using Shell Eggs Inoculated with Salmonella Serotypes Enteritidis and Heidelberg

Abstract

Salmonella Enteritidis has been associated with eggs and egg products for a long time. However, Salmonella Heidelberg is now also being associated with eggs and egg products. Experiments were therefore done to determine which cooking methods were considered to be safe. The following American Egg Board cooking methods were chosen: hard and soft cooked, scrambled, over-easy, sunny-side-up, and poached using a pan insert and the free flowing method. Shell eggs were purchased from the grocery store and candled for cracks. The eggs were then inoculated with a Salmonella cocktail and cooked. The microbiological testing was done using the USDA approved methods for Salmonella recovery. Findings indicate that the American Egg Board(AEB) hard cooked, soft cooked, and poaching methods are safe. The same is not true for the over-easy and scrambled egg cooking methods, in which SE or SH were recovered from cooking product. The over-easy came back positive for SH, and scrambled came back positive for SE PT4 and PT30. The free poached egg cooking method came back positive for SH and SE PT4 in two of the 30 cooked samples. Given this low frequency of SE and SH recovery, the over-easy and scrambled cooking methods can be considered reasonably safe. The free poached method could be considered safe if cooked to the maximum of five min. The sunny-side-up cooking method had a total of 19 of 30 samples that were Salmonella positive after cooking, with some samples having a combination of multiple salmonellas. The sunny-side-up method should be considered unsafe.