Suppression of salmonella enteritidis in preparation of Japanese onsen tamago

Salmonellosis is often related to eggs and egg products such as onsen tamago. Yet, the cooking methods for preparing Japanese onsen tamago have not been standardized. This study is to preliminarily standardize the cooking conditions for onsen tamago. This study aims at investigating the determining factors for suppressing Salmonella Enteritidis in onsen tamago. The results show that cooking temperature and cooking duration are the two critical factors determining the survival of Salmonella Enteritidis in onsen tamago. Large sized eggs cooked for 14 min at a temperature of 70°C can effectively inactivate Salmonella Enteritidis while preserving the texture of the eggs. Findings of this study can help standardize the cooking conditions for preparing safe onsen tamago, or even other types of eggs and egg products, to minimize salmonellosis. Novelty impact statement: Cooking temperature and cooking duration are the two critical factors determining the survival of Salmonella Enteritidis and the texture of Japanese onsen tamago. When eggs are cooked at a temperature of 70°C, core temperature of the egg yolks was increased in a trend of natural logarithm to the final temperature of 63.6°C in 16 min. Large-sized eggs cooked by the method for 14 min can effectively inactivate Salmonella Enteritidis (core temperature at 62.2°C and >4 log reduction) while preserving the texture of the eggs.