Application of high pressure processing for prevention of greenish-gray yolks and improvement of safety and shelf-life of hard-cooked peeled eggs

Hafiz Muhammad Shahbaz, Bora Jeong, Jeong Un Kim, Namho Ha, Hyunah Lee, Sang Do Ha, Jiyong Park

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Hard-cooked peeled eggs (HCEs) are value-added ready-to-use egg products susceptible to microbial re-contamination during post-processing stages. A post-processing terminal step using high hydrostatic pressure (HHP 500, 550, 600 MPa for 5 min at 25 °C) was applied to ensure maximum safety of HCEs and the effects of processing were evaluated and compared with a commercial thermal post-processing intervention using steam heating. A significant discoloration in the form of greenish-gray yolks was observed in HCEs after steam heat post-processing due to overcooking. Color values of the HCE yolk (L*, a*, b*) after HHP post-processing were not significantly different (P > 0.05) from non-post-processed HCEs. Non-thermal and thermal post-processing interventions each kept the growth of microbial contaminants at < 104 CFU/g throughout 45 days of refrigerated storage. Microbial counts in non-post-processed HCEs exceeded this safety limit within 3 d. Sensory analysis showed significantly higher preference scores for the quality attributes of HCEs post-processed with HHP than with steam heating. Inactivation curves of Salmonella Enteritidis inoculated onto HCE surfaces after all HHP levels were well-fitted to the biphasic mathematical model. HHP post-package pasteurization at 550 MPa for 5 min showed potential as a terminal non-thermal kill step for commercial production of HCEs. Industrial relevance A non-thermal post-processing intervention using HHP can be considered as a terminal kill step during commercial production of HCEs to ensure maximum microbiological safety and to extend the shelf life of HCEs without formation of unappetizing greenish-gray yolks. The biphasic mathematical model can be used to predict growth and survival of Salmonella Enteritidis in HCEs and to conduct a risk analysis of this type of food products.

Original languageEnglish
Pages (from-to)10-17
Number of pages8
JournalInnovative Food Science and Emerging Technologies
Publication statusPublished - 2018 Feb

Bibliographical note

Funding Information:
This study was supported by the High Value-Added Food Technology Development Program (Grant no. 114035-02 ), Ministry of Agriculture, Food and Rural Affairs , South Korea.

Publisher Copyright:
© 2017 Elsevier Ltd

All Science Journal Classification (ASJC) codes

  • Food Science
  • Chemistry(all)
  • Industrial and Manufacturing Engineering


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